A ketogenic diet for beginners

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A keto or ketogenic diet is a very low-carb diet, which can help you burn fat more effectively. Many people have already experienced its many proven benefits for weight loss, health and performance.1
Here you’ll learn how to eat a keto diet based on real foods. You’ll find visual guides, recipes, meal plans and a simple 2-week get started program, all you need to succeed on keto.

1. Intro: What is the keto diet?

We make it simple to understand a keto diet and do it right, using our video course above.

The entire course is available here. Alternatively, just keep reading below.


What “keto” means


The “keto” in a ketogenic diet comes from the fact that it allows the body to produce small fuel molecules called “ketones”.2 This is an alternative fuel source for the body, used when blood sugar (glucose) is in short supply.

Ketones are produced if you eat very few carbs (that are quickly broken down into blood sugar) and only moderate amounts of protein (excess protein can also be converted to blood sugar).

The liver produces ketones from fat. These ketones then serve as a fuel source throughout the body, especially for the brain.

The brain is a hungry organ that consumes lots of energy every day, and it can’t run on fat directly. It can only run on glucose… or ketones.34

On a ketogenic diet, your entire body switches its fuel supply to run mostly on fat, burning fat 24-7. When insulin levels become very low, fat burning can increase dramatically. It becomes easier to access your fat stores to burn them off.5 This is great if you’re trying to lose weight, but there are also other less obvious benefits, such as less hunger and a steady supply of energy. This may help keep you alert and focused.6

When the body produces ketones, it enters a metabolic state called ketosis. The fastest way to get there is by fasting – not eating anything – but nobody can fast forever.7

A keto diet, on the other hand, can be eaten indefinitely and also results in ketosis. It has many of the benefits of fasting – including weight loss – without having to fast.8

Learn more about ketosis


Who should NOT do a ketogenic diet?

There are many myths and misunderstandings about a keto diet, but for most people it appears to be very safe.9 There are, however, three groups that often require special consideration:

  • Do you take medication for diabetes, e.g. insulin? More
  • Do you take medication for high blood pressure? More
  • Do you breastfeed? More

Are you a doctor or do you need your doctor to help you with medications on a keto diet? Have a look at our low carb for doctors guide.


Disclaimer: While the ketogenic diet has many proven benefits, it’s still controversial. The main potential danger regards medications, e.g. for diabetes, where doses may need to be adapted (see above). Discuss any changes in medication and relevant lifestyle changes with your doctor. Full disclaimer

This guide is written for adults with health issues, including obesity, that could benefit from a ketogenic diet.

Controversial topics related to a keto diet, and our take on them, include saturated fats, cholesterol, whole grains, red meat and restricting calories for weight loss.


2. What to eat on a keto diet

Here are typical foods to enjoy on a ketogenic diet. The numbers are net carbs, i.e. digestible carbs, per 100 grams.10 To remain in ketosis, lower is generally better:

Keto diet foods: Natural fats (butter, olive oil); Meat; Fish and seafood; Eggs; Cheese; Vegetables that grow above ground

The most important thing for reaching ketosis is to avoid eating too many carbs. You’ll probably need to keep carb intake under 50 grams per day of net carbs, ideally below 20 grams. The fewer carbs, the more effective it appears to be for reaching ketosis, losing weight or reversing type 2 diabetes.11

Counting carbs can be helpful at first. But if you stick to our recommended foods and recipes you can stay keto even without counting.

Detailed list of what to eat on a keto diet


Try to avoid

Here’s what you should avoid on a keto diet – carb foods containing a lot of sugar and starch. This includes starchy foods like bread, pasta, rice and potatoes. These foods are very high-carbs.

Foods to avoid on a ketogenic diet: bread, pasta, rice, potatoes, fruit, beer, soda, juice, candy

The numbers are grams of net carbs per 100 grams, unless otherwise noted.12

This means that on a keto diet you’ll basically need to avoid sugary foods completely, as well as starchy foods like bread, pasta, rice and potatoes. Also avoid processed foods, and instead follow our keto diet advice.

Furthermore, the food should primarily be high in fat, and only moderately high in protein, as excess protein can be converted to blood sugar in the body. Avoid low-fat diet products. A rough guideline is about 5% energy from carbohydrates (the fewer carbs, the more effective), 15-25% from protein, and around 75% from fat.13

More specific advice on what to eat – and what not to eat

What to drink

Low-carb drinks

So what do you drink on a ketogenic diet? Water is the perfect drink, and coffee or tea are fine too. Ideally, use no sweeteners, especially not sugar.14 A small amount of milk or cream in your coffee or tea is OK (but beware of caffe latte!). The occasional glass of wine is fine too.

For more, have a look at our full guides to keto drinks and keto alcohol.


Visual keto diet guides

For more on specific topics – like what fruits or nuts to eat on a ketogenic diet – check out our popular visual guides:

Keto diet recipes

We have over 300 fantastic keto diet recipes. Below are a few popular examples:


Diet meal plans

Here are two weeks worth of recipes for breakfast, lunch and dinner on a ketogenic diet:

14-day keto diet plan

Get 80+ prepared weekly keto meal plans, complete with all recipes, shopping lists and more, with our premium meal planner tool (free trial). Our prepared meal plans include quick & easy, budget and family-friendly weeks, etc.

Our meal planner includes the ability to change meals to any of our hundreds of recipes, skip meals, or even construct your own keto meal plans from scratch, using our recipes, and share them.


How low carb is a keto diet?

The fewer carbs you eat, the more effective it seems to be for weight loss, appetite suppression and type 2 diabetes reversal, etc.15 A keto diet is a very strict low-carb diet, containing less than 20 grams of net carbs per day, and thus it tends to be highly effective.

Here are three possible examples of how low-carb meals can look, based on how many carbs you aim to eat in a day. Note that only the left plate is reliably ketogenic:

We recommend starting out by following the dietary advice as strictly as you can. When you’re happy with your weight and health, you could carefully try eating a few more carbs (if you want to). Learn more


Get started

For everything you need to get started – eating plans, shopping lists, daily tips and troubleshooting – just sign up for our free 2-week keto diet challenge.



Here’s our leaflet with basic keto advice. Feel free to print it out, put it on your fridge, or give it to your curious friends:




Keto diet advice in 40 languages

We have keto diet advice available in 40 languages, including our entire Diet Doctor site in Spanish and Swedish.



3. Why to eat a keto diet – the health benefits

The benefits of a ketogenic diet are similar to those of other low-carb diets, but it appears to be more powerful than liberal low-carb diets.16 Think of keto as a super-charged low-carb diet, maximizing the benefits. However, it can also be harder to do, and it may increase the risk of side effects a bit.


Keto and weight lossLose weight

Turning your body into a fat-burning machine can be beneficial for weight loss. Fat burning is significantly increased, while insulin – the fat-storing hormone – levels drop greatly.17 This appears to make it far easier for body fat loss to occur, without hunger.18

More than 30 high-quality scientific studies show that, compared to other diets, low-carb and keto diets result in more effective weight loss.19

The keto diet and appetite controlAppetite control

On a keto diet you’re likely to gain a new control over your appetite. When your body burns fat 24-7, it has constant access to weeks or months of stored energy, significantly reducing feelings of hunger. It’s a very common experience, and studies prove it.20

This makes it easy to eat less and lose excess weight – just wait until you’re hungry before you eat.21 It also makes intermittent fasting easier, something that can super-charge efforts to reverse type 2 diabetes and speed up weight loss, beyond the effect of keto only.22

Plus, you’ll save tons of time and money by not having to snack all the time. Many people only feel the need to eat twice a day on a keto diet (often skipping breakfast), and some just once a day.23

Not having to fight feelings of hunger could also potentially help with problems like sugar or food addiction, and possibly some eating disorders, like bulimia, as well.24 At least feeling satisfied can be part of the solution. Food can stop being an enemy and become your friend – or simply fuel, whatever you prefer.

Low carb and diabetes reversalControl blood sugar and reverse type 2 diabetes

A ketogenic diet helps control blood sugar levels. It is excellent for managing type 2 diabetes, sometimes even leading to complete reversal of the disease. This has been proven in studies.25 It makes perfect sense since keto lowers blood-sugar levels, reduces the need of medications and reduces the potentially negative impact of high insulin levels.26

As a keto diet may even reverse existing type 2 diabetes, it’s likely to be effective at preventing it, or reversing pre-diabetes.27

How to reverse type 2 diabetes

200+ success stories

Low carb and diabetes reversalImproved health markers

There are many studies showing that low-carb diets improve several important risk factors for heart disease, including the cholesterol profile (HDL, triglycerides), while total cholesterol and LDL levels are usually impacted fairly modestly.28

It’s also typical to see improved blood sugar levels, insulin levels and blood pressure.29

These commonly improved markers are connected to something called “metabolic syndrome”, and improvements in weight, waist circumference, diabetes type 2 reversal etc.30

My health markers after 10 years on a keto diet 31

Keto diet and constant energy and brain performanceEnergy and mental performance

Some people use ketogenic diets specifically for increased mental performance. Also, it’s common for people to experience an increase in energy when in ketosis.32

On keto, the brain doesn’t need dietary carbs. It’s fueled 24-7 by ketones, an effective brain fuel.

Therefore, ketosis results in a steady flow of fuel (ketones) to the brain, thus avoiding problems experienced with big blood sugar swings.33 This may sometimes result in improved focus and concentration, and resolution of brain fog, with an improved mental clarity.34

Keto and IBSA calmer stomach

A keto diet can result in a calmer stomach, less gas, less cramps and pains, often resulting in improvements in IBS symptoms.35

For some people this is the top benefit, and it often only takes a day or two to experience it.36 Learn more

Low carb and weight lossIncreased physical endurance

Ketogenic diets can in theory increase your physical endurance by improving your access to the vast amounts of energy in your fat stores.37

The body’s supply of stored carbohydrates (glycogen) only lasts for a couple of hours of intense exercise, or less. But your fat stores carry enough energy to potentially last for weeks.38

Beyond this effect, another potential benefit is the reduction in body fat percentage that can be achieved on a keto diet (see weight loss, above). This reduction in body fat weight is potentially valuable in a number of competitive sports, including endurance sports.39

How to maximize endurance on a keto diet

Keto diets and epilepsyEpilepsy

The ketogenic diet is a proven and often effective medical therapy for epilepsy that has been used since the 1920s. Traditionally it was used primarily for children, but in recent years adults have benefited from it as well.40

Using a ketogenic diet in epilepsy can allow some people to take less or no anti-epileptic drugs, while potentially still remaining seizure-free. This may reduce drug side effects and thus increase mental performance.41


More possible benefits

The benefits above are the most common ones. But there are others that are potentially even more surprising and – at least for some people – life changing. Did you know that a keto diet can help treat high blood pressure,42 may result in less acne,43 may help control migraine,44 might help with certain mental health issues and could have a few other potential benefits?

Follow the links below for more knowledge, stories and science:

Other potential benefits

There’s even science-based speculation that a ketogenic diet might increase longevity and potentially help treat or reduce the risk of cancer.45 It’s also being used as an experimental treatment for some people with Parkinson’s disease.46


Success stories on a keto diet

We’re always happy to receive stories from people who’ve used a keto diet to revolutionize their health. We’ve been sent thousands of such stories, and we publish some of the most amazing ones – over 250 so far – for anyone to read.47

Here are a few of them:

  • Keto and intermittent fasting: "I am completely blown away by the changes"
  • How Melissa lost 100 pounds with a keto diet, and kept it off for 15 years
  • A low-carb diet: Maintaining a 70-pound weight loss for five years
  • Reversing type 2 diabetes in only 2.5 months with keto and fasting



Top success story videos

  • A low-carb story with Dr. Campbell Murdoch
  • My success story with Gillian Szollos


Share your story!



4. How to get into ketosis on a keto diet

20 grams of carbs in two waysHere are the seven most important things to increase your level of ketosis, ranked from most to least important:

  1. Restrict carbohydrates to 20 digestible grams per day or less – a strict low-carb or keto diet. Fiber does not have to be restricted, it might even be beneficial for ketosis.48  
    How much is 20 grams of carbs? Use our visual guide to find out. Or simply use our keto recipes and meal plans, they are designed to keep you under 20 grams with no counting required.
    Note that quite often, just restricting carbs to very low levels results in ketosis. So this may be all you need to do. But the rest of the list below will help make sure that you’re successful.
  2. Restrict protein to moderate levels. On a ketogenic diet you should eat the protein you need, but not much more. This is because excess protein is converted to glucose in the body, reducing ketosis.
    If possible, stay at about 1.5 gram of protein per day, per kg of body weight – about 100 grams of protein per day if you weigh 70 kilos (154 pounds).49
    A common mistake that stops people from getting into ketosis is too much protein. Our keto recipes are designed with the right amount of protein. If you want more details check out our protein guide.
  3. Eat enough fat to feel satisfied.50 This is the big difference between a keto diet and starvation, that also results in ketosis. A keto diet is sustainable, but starvation is not.51
    When starving you’re likely to feel tired and hungry and give up, but a ketogenic diet is sustainable and can make you feel great.52 So eat enough to feel satisfied, and if you’re hungry all the time, you should probably add more fat to your meals (like more butter, more olive oil, etc.). Our keto recipes have the needed fat included.
  4. Avoid snacking when not hungry. Eating more often than you need, just eating for fun and because there’s food around, reduces ketosis and slows down weight loss.53 Though using keto snacks will minimize the damage, and is fine when you’re hungry.
  5. If necessary, add intermittent fasting. For example, skip breakfast and only eat during 8 hours of the day, fasting for 16 hours (i.e. 16:8 fasting). This is very effective at boosting ketone levels, as well as accelerating weight loss and type 2 diabetes reversal.54 It’s also usually easy to do on keto.
  6. Add exercise – adding any kind of physical activity while on low carb can increase ketone levels moderately.55 It can also help speed up weight loss and diabetes type 2 reversal slightly.56 Exercise is not necessary to get into ketosis, but it may be helpful.
  7. Sleep enough – for most people at least seven hours per night on average – and keep stress under control. Sleep deprivation and stress hormones raise blood sugar levels, slowing ketosis and weight loss a bit.57 Plus they might make it harder to stick to a keto diet, and resist temptations.58 So while handling sleep and stress will not get you into ketosis on it’s own, it’s still worth thinking about.
Bottom line: To get into ketosis, restrict carbs to very low levels, preferably below 20 net carbs per day. That’s a ketogenic diet, and it’s by far the most important thing for ketosis to occur.

Should you need to increase the effect, implement more steps from the list above, starting from the top.


No products required

Note what’s not on the list above: you likely do not need expensive supplements, like exogenous ketones or MCT oil (medium-chain triglycerides). These supplements will likely not help you lose weight or reverse disease. At least there’s no evidence for that.59


Ketone supplements for example, do not lower insulin or blood sugar, and they do not increase fat burning.60 Thus it’s hard to believe that they would have any direct benefits for weight loss or type 2 diabetes reversal.61

People claiming huge benefits of these supplements – despite the lack of solid scientific support – may sometimes have a financial reason to believe in the supplements. Some of these products are sold under a multi-level marketing arrangement, where sales people are paid based on commission. For example, the company Prüvit sells drinkable ketones, called KETO//OS with a multi-level marketing structure.

The salesperson might tell you that their product is fantastic and has changed their lives and makes you lose weight etc. But these benefits are basically unproven and unlikely. Take all such stories with a grain of salt.

What these ketone supplements might do is possibly improve mental and physical performance for a short time. To the best of our knowledge, this potential and often mentioned benefit is also unproven. They do raise blood levels of ketones, an effect that can last for one up to a few hours.

So… I’m not saying don’t buy these supplements. Perhaps you do want to try them for yourself, see how they make you feel. But you don’t need them to be successful on a keto diet. And they are probably, for most people, a waste of money. Here’s our big test of keto supplements:

Keto supplements – do they work?

5. How to know you’re in ketosis

After starting a ketogenic diet, how do you know if you’re in ketosis? It’s possible to measure it by testing urine, blood or breath samples. But there are also telltale symptoms, that require no testing:

Symptoms of ketosis: dry mouth, thirst, frequent urination

  • Dry mouth and increased thirst. Unless you drink enough and get enough electrolytes, like salt, you may feel a dry mouth. Try a cup of bouillon or two daily, plus as much water as you need. You may also feel a metallic taste in your mouth.62
  • Increased urination. A ketone body, acetoacetate, may end up in the urine. This makes it possible to test for ketosis using urine strips. It also – at least when starting out – can result in having to go to the bathroom more often. This may be the main cause of the increased thirst (above).
  • Keto breath. This is due to a ketone body called acetone escaping via our breath.63 It can make a person’s breath smell “fruity”, or similar to nail polish remover. This smell can sometimes also be felt from sweat, when working out. It’s often temporary. Learn more

Other, less specific but more positive signs include:

  • Reduced hunger. Many people experience a marked reduction in hunger on a keto diet.64 This may be caused by an increased ability of the body to be fueled by its fat stores. Many people feel great when they eat just once or twice a day, and may automatically end up doing a form of intermittent fasting. This saves time and money, while also speeding up weight loss.65
  • Possibly increased energy. After a few days of feeling tired (the “keto flu“) many people experience a clear increase in energy levels. This can also be experienced as clear thinking, a lack of “brain fog” or even a sense of euphoria.66


Measuring ketosis

ketone meters
There are three ways to measure for ketones, which all come with pros and cons. Note that we have no affilations with any of the brands mentioned here.67


1. Urine stripsketostix

Urine strips are the simplest and cheapest way to measure ketosis. It is the first option for most beginners on a keto diet.

Dip the strip in your urine, and 15 seconds later the color change will show you the presence of ketones.68 If you get a high reading (a dark purple color), you’ll know that you’re in ketosis.

Pro: Ketone strips are available in regular pharmacies or via Amazon, and they’re very cheap. A strongly positive test reliably proves that you’re in ketosis.

Con: Results can vary depending on how much fluid you drink. By drinking more water, you dilute the concentration of ketones in the urine and thus a lower level of ketones will be detected on the strips. The strips don’t show a precise ketone level. Finally, and most importantly, as you become increasingly keto-adapted and your body reabsorbs ketones from the urine, urine strips may become unreliable, even if you’re in ketosis.

This happens when the body becomes more adapted to using ketones, meaning that they increasingly stay in the blood to be used as energy instead of being lost through the urine.

After 3 weeks the kidneys have been found to excrete ketones at one third the rate than after just 4 days despite having the same blood ketone levels:

Diabetes 1985: Ketone body production and disposal in diabetic ketosis: a comparison with fasting ketosis

Thus, the test may sometimes stop working – always showing a negative result – when you’ve been in ketosis for several weeks.

Order urine strips at Amazon


2. Breath-ketone analyzers

ketonixBreath-ketone analyzers are a simple way to measure ketones69 in your breath. At $169 and up they are more expensive than urine strips. But they are cheaper than blood-ketone meters in the long run, as they are reusable any number of times.

These analyzers do not give you a precise ketone level when used on their own, but provide a color code for the general level.70

You can also hook it up to a computer or mobile phone (newer models) and get a more exact ketone number via the app. According to the manufacturer the device gives a decent correlation with blood ketones in most but not all situations.

Pro: Reusable, simple test.

Con: Does not always correlate well with blood ketones. Not always accurate, and can in some situations show entirely misleading values.For example, if you recently ate a lot of carbs e.g. a pizza, this can result in misleading high values on the Ketonix. More expensive than urine strips, and higher cost upfront than a blood meter.

Order Ketonix

Video: Using breath-ketone analyzers


3. Blood-ketone metersBlood ketone meters: Precision extra and Keto-Mojo

Blood-ketone meters show an exact and current level of ketones in your blood.71 They are the gold standard and the most exact way to measure your ketosis level on a ketogenic diet. The major disadvantage, however, is that they are quite expensive, formerly at least $2 per test.72 Now it’s possible to get cheaper tests.

A new startup called Keto-Mojo is offering blood ketone testing for about $1 per test. In our big test of blood-ketone meters we find that it may be the best option if price is a concern.

GOOD: Exact, reliable.

BAD: Still expensive (at least $1 per test). Requires pricking your finger for a drop of blood.

Which is the best ketone meter on the market? The big test

Order the Keto-Mojo meter

Order the blood-ketone meter Precision Xtra with everything included, at Amazon


How to reach optimal ketosis

Getting into ketosis on a ketogenic diet is not a black or white thing. It’s not like you’re either in ketosis, or out of ketosis. Instead, you can be in different degrees of ketosis, as this chart demonstrates.73 The numbers below refer to values when testing blood ketone levels.

The Ketone Zone

  • Below 0.5 mmol/l is not considered “ketosis”, although a value of, say, 0.2 demonstrates that you’re getting close. At this level, you’re still far away from maximum fat-burning.
  • Between 0.5 – 1.5 mmol/l is light nutritional ketosis. You’ll likely be getting a good effect on your weight, but perhaps not optimal.74
  • Around 1.5 – 3 mmol/l is called optimal ketosis and is sometimes recommended for maximum mental and physical performance gains.75 It tends to maximize fat burning, which may increase weight loss.76
  • Over 3 mmol/l is higher than necessary. It will probably achieve neither better nor worse results than being at the 1.5–3 level. Higher numbers can also sometimes mean that you’re not getting enough food (“starvation ketosis”). For type 1 diabetics, it can be caused by a severe lack of insulin that requires urgent attention.77
  • Over 8–10 mmol/l: It’s normally impossible to get to this level just by eating a keto diet. It means that something is wrong. The most common cause by far is type 1 diabetes, with severe lack of insulin.78 Symptoms include feeling very sick with nausea, vomiting, abdominal pain and confusion. The possible end result, ketoacidosis, may be fatal and requires immediate medical care. Learn more

Learn a keto diet from the experts

  • Low-carb living
  • Keto-adaptation and performance


Optimal ketosis experimentStories about achieving long-term ketosis

Here are the three reports from a 2-month experiment in reaching optimal ketosis:

  1. Experiment: Optimal ketosis for weight loss and increased performance
  2. Four weeks of a strict keto diet and ketone monitoring
  3. Final report: Two months of a strict keto diet and ketone monitoring

Do I have to reach optimal ketosis to experience the benefits?

In short, no. Many of the benefits, such as weight loss, are experienced at lower levels of ketosis (above 0.5).

However, you might need to reach higher levels of ketosis for high-level physical performance. There’s also a time element involved, it takes weeks or even a few months for the body to adapt completely. For more on this, here’s an interesting article from two of the top keto researchers in the world, Stephen Phinney and Jeff Volek:

Virta Health: Keto-adaptation – some clues to its complexity




6. Practical keto diet guides

A keto diet can be really simple, but it helps to learn some basic new skills. How do you prepare easy and enjoyable meals, like keto breakfasts? Have you shunned fat for years and don’t know how to get more in your diet? How do you eat out and still stay keto?

These tips and guides will help you get new skills and answer all the common keto questions.

Keto breakfastBreakfast

How should you start your keto day? If you love bacon and eggs dig in! If you don’t, some great keto breakfasts have no eggs at all.

Have you been told that “breakfast is the most important meal of the day”? That’s likely not true.79 If you are not hungry when you wake up, feel free to skip breakfast or just have a cup of coffee. Reduced hunger is common on a keto diet, so don’t worry about skipping any meal.80

If you are hungry when you wake up but are short on time, many keto breakfasts are tasty, filling and fast. All keto breakfasts

Keto mealsMeals

Hmmm, what to eat for lunch or dinner? Daily meal planning can be as simple as meat, fish or chicken mains with a salad, or vegetable side – with melted butter, cheese, or a yummy full-fat sauce. We have hundreds of choices for delicious keto meals

A keto diet on a budgetA keto diet on a budget

Many people believe that a keto diet is expensive, and it can be. After all, good quality food is often more costly than cheaper and unhealthier options. But there are many ways to make a keto diet cheap, and in this guide you’ll learn all about it

Eating more fat on a keto dietHow to eat more fat

For decades we have been told, wrongly, to fear fat.81 Now we know fat is satiating, healthy and makes food taste great.

Do you need tips and tricks for how to add fat back into your food? What fats to use, olive oil or butter? And just how much fat do you need each day? Tip: if you are constantly feeling hungry on a keto diet, eat more fat.

Here’s how to add fat back

Keto breadBread

Bread is one of the most common things that people may miss on a ketogenic diet. But fear not, there are plenty of good bread options that are very low in carbs, and that can be eaten even on a keto diet. Learn more

Dining out on a keto dietDining out

How do you eat keto at buffets, at a friend’s house or at fast­-food restaurants? Avoid the starchy foods (like bread or pasta) and ask for additional natural fat, like butter or olive oil, if you need it. Learn more

How to cheat on a keto dietKeto diet cheating

To cheat or not to cheat? This guide will help you decide, and if you do decide to cheat, it will help you do it smarter

Avoid processed foods on a keto dietAvoiding special products

Another common mistake on a ketogenic diet is being fooled by the creative marketing of special “low-carb” products. Remember: An effective keto diet for weight loss should be based on real food.

Low-carb products like chocolate, candy, pasta and bread often use all kinds of deceptive marketing, while being just junk food – including carbs – in disguise. Learn more

More guides

Do you want more keto diet guides? We have more keto diet guides!

All keto guides




7. Potential side effects of a keto diet

When you suddenly switch your body’s metabolism from burning carbs (glucose) to fat and ketones you may have some side effects as your body gets used to its new fuel, especially during day 2-5.

Symptoms can include headache, tiredness, muscle fatigue, cramping and heart palpitations. These side effects are short-lived for most people, and there are ways to minimize or cure them (see below).

Another option to reduce potential side effects is to gradually decrease your consumption of carbs over a few weeks. But with a slower start you’ll likely not see as dramatic results or feel the positive benefits as strongly.

Therefore we recommend you stop sugar and starches all at once. You will likely lose a number of pounds within days. While much of the initial rapid weight loss is water weight (reduced swelling), it’s still a highly motivating and inspiring way to start your keto journey.

Keep reading for more about common side effects and how to handle them.


Keto fluKeto flu

Most people who start a ketogenic diet will experience some symptoms of the “keto flu“. This is what you may feel, more or less, a few days after you’ve started a keto diet:

  • Headache
  • Fatigue
  • Dizziness
  • Light nausea
  • Difficulty focusing (“brain fog”)
  • Lack of motivation
  • Irritability

These initial symptoms usually disappear within a week, as your body adapts to increased fat burning.

The main cause of the keto flu is that carb-rich foods can result in water retention (swelling) in the body.82 When you start a low-carb diet much of this excess fluid is lost. You may notice increased urination, and with that some extra salt is lost too.

This can result in dehydration and a lack of salt, before your body adapts. This appears to be the reason behind most of the symptoms of the keto flu.

You can reduce or even eliminate these symptoms by making sure you get enough water and salt. One simple way to do this is to drink a cup of bouillon or broth, 1-2 times per day.83

More about keto flu and how to minimize it

Do you need electrolyte supplementation on a keto diet?

Other common keto diet side effects

Apart from the keto flu, there are six more relatively common side effects. More water and salt can be helpful with most of them as well. Beyond that, there are more specific treatments for these issues:

Less common keto diet side effects

These side effects only affect a small minority of people on a ketogenic diet, and there are ways to handle them:

Keto diet controversies

Most side effects of a keto diet are minor and temporary. But there are a lot of controversies and some myths, that scare people.

Like the idea that your brain will cease functioning unless you eat lots of carbs. It’s a myth, based on a lack of understanding of the way the body works in ketosis (switching the fuel supply of the brain to ketones). Learn more

Another common misunderstanding is mixing up normal ketosis – resulting from a keto diet – with the dangerous medical emergency ketoacidosis. They are two very different things. Ketoacidosis does not happen just from eating a keto diet.84

There are several more common keto diet controversies. Will keto kill your kidneys or destroy your bones? Will it stop your thyroid from working? Read all about them on our low-carb and keto controversies page, or choose one below.

Saturated fat   |   Cholesterol   |   Brain needs carbs   |   Environment   |   Nutrients   |   Thyroid   |   Kidneys   |   Depression   |   Exercise   |   Gut bacteria   |   Osteoporosis   |   Ketoacidosis


8. Keto diet Q&A, troubleshooting and resources

Keto questions and answersThere are many common questions about keto, and we do our best to answer them all. Feel free to check out our full keto diet FAQ, or choose one of the questions below:


How much weight will I lose on a keto diet?

Results vary widely. Most people lose 2-4 pounds (1-2 kg) during the first week. This is mainly water weight. After this it’s common to lose about 1 pound (0.5 kg) of excess fat weight per week. However, some lose much faster (often younger men), some a bit slower (often women over 40).

You can speed up the process or break a weight loss plateau by following our top tips.

When you approach your normal body weight, the weight loss will slow. As long as you eat when you’re hungry you’ll eventually stabilize your weight even if you stay on a ketogenic diet.


How do I track my carb intake?

If you use our keto recipes and keto meal plans you’ll stay under 20 net grams of carbs per day, with no need to count.

Using our keto foods guidelines and visual guides will make it simple to estimate roughly how many carbs you eat in a day.

If you want to count carbs exactly, the most popular way is with apps like MyFitnessPal or Chronometer.


What happens after I reach my health and weight goals on a keto diet?

Once you reach your goals you can either keep eating keto (to maintain the effect), or you can try adding a bit more carbs. In the latter case the effect of the keto diet will be slightly weaker, and you may or may not regain some weight.

If you completely revert to your old habits, you’ll slowly return to the weight and health situation you had before. It’s like exercising – if you stop doing it, you’ll slowly lose the benefits. As you may expect, a keto diet, like exercise, only works when you do it.


Further questions and answers


Resources to learn more

Get free video courses, keto recipes and news updates like over 500,000 people:


Top keto diet presentations

  • Understanding and treating type 2 diabetes – Dr. Jason Fung
  • Exploiting cancer metabolism with ketosis


Keto diet interviews

  • My success story with Gillian Szollos
  • Achieve ketosis through fasting


Keto and LCHF basics

Here are a few of our hundreds of keto TV videos, these ones are focussed on keto basics:

  • Keto for beginners: Introduction
  • My success story with Kenneth Russell


Low-carb and keto eventsUpcoming keto events

Do you want to meet other low-carb and keto fans and experts? Here’s an updated list of upcoming low-carb and keto events around the world


For more low-carb and keto sites, check out our recommended sites.


The Art and Science of Low-Carbohydrate Performance by Stephen Phinney and Jeff Volek.


For podcasts about a keto diet, check out the Diet Doctor Podcast or our list of other top low-carb and keto podcasts.


Ketogenic diet foods – what to eat
14-day keto diet plan


  1. Scientific studies now prove that compared to other diets, low carb or keto diets are often more effective for weight loss, and for improving certain health markers.

    This has been demonstrated in several meta-analyses of all top studies, for example this one:

    PLOS ONE 2015: Dietary intervention for overweight and obese adults: comparison of low-carbohydrate and low-fat diets. A meta-analysis [strong evidence]

    Here are two selected top studies (RCTs) demonstrating this:

    More studies: The science of low carb

    We currently do not know how many people have benefited from low-carb or ketogenic diets. A conservative guess might put this number in the millions. Low-carb diets like the Atkins diet have been bestsellers in book format for decades, and currently the ketogenic diet is very popular.

  2. There are three different ketones, or “ketone bodies” used as fuel by the body. They are:

    1. Acetone
    2. Acetoacetate
    3. Beta-hydroxybutyrate


    Learn far more than you’ll ever need about ketones here:

    Dr. Peter Attia: Ketosis – advantaged or misunderstood state? (Part I)

  3. The brain consumes about 20% of the body’s required energy every day, despite only representing 2% of the body’s mass.

    This is a good bonus for weight loss, if you can get your hungry brain to burn fat for you, 24-7.

    Another note: ketosis is why the old idea that “the brain needs carbohydrates” is wrong – the brain requires limited amounts of glucose even in ketosis, but the body can create that glucose from protein and fat in a process called gluconeogenesis.

    Learn more:

    Critical Care 2011: Clinical review: ketones and brain injury

  4. It’s a common misconception that all of the body only runs on ketones when on a keto diet. The truth is that most of the body – including the muscles – can burn fat directly. It would be a waste to have the liver first convert them into ketones. This is mostly necessary for the brain.

  5. Low-carb diets have been demonstrated to result in more weight loss than other diets:

    PLOS ONE 2015: Dietary intervention for overweight and obese adults: comparison of low-carbohydrate and low-fat diets. A meta-analysis [strong evidence]

    Low-carb diets might even increase metabolism – potentially increasing fat burning – by between 200 and 500 calories per day:

    British Medical Journal 2018: Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial [moderate evidence] Analysis

    As a sidenote: the increased fat burning can use either body fat, or dietary fat, or (usually) both. This means that eating more fat than you need to stay satisfied can slow down the burning of body fat stores. If you’re aiming to lose weight, only eat when you’re hungry. Learn more

  6. This is something that is often reported by people on a keto diet [very weak evidence].

    The scientific support is not strong. Here are references showing minor signs of improvements:

  7. The ketosis experienced after a longer period of fasting is called starvation ketosis. Starvation is not sustainable.

  8. The ketosis experienced on a ketogenic diet is often called nutritional ketosis. This seems to be sustainable long term.

    Studies have demonstrated that ketosis can be maintained for years, e.g. in children treated with a ketogenic diet for epilepsy, and for at least a year or two when treating obesity or type 2 diabetes.

    It may even be possible to stay on a ketogenic diet indefinitely. While it may be quite challenging for most people to do it consistently for years, there is no obvious or proven upper limit for how long nutritional ketosis can be maintained.

  9. The main fear about lower-carb and higher-fat diets have always been an increase in the risk of heart disease. However, interventional studies so far indicate that if anything the risk appears to decrease:

  10. Net carbs per 100 grams, i.e. what percentage of that food that is made up of digestible carbs.

    100 grams = 3.5 ounces.

    Net carbs (or “digestible carbs”) are total carbs minus fiber. Fiber is OK to eat, since it doesn’t directly affect blood sugar levels.

    Learn more about carbs and net carbs on a keto diet

  11. This is mainly based on the consistent experience of experienced practitioners, and stories from people trying different levels of carb restriction [weak evidence].

    There is not yet any RCT that has actually tested two low-carb diets of varying strictness head-to-head. But RCTs of strict low-carb diets appear to often show better results, compared to RCTs of more moderate or liberal low-carb diets.

    This makes logical sense: if something has an effect, doing more of it often has a stronger effect.

    RCTs of low-carb interventions for weight loss

  12. Net carbs per 100 grams, i.e. what percentage of that food that is made up of digestible carbs.

    100 grams = 3.5 ounces.

    Net carbs (or “digestible carbs”) are total carbs minus fiber. Fiber is OK to eat on keto, since it doesn’t affect blood sugar levels.

  13. Younger, fit people who exercise a lot may be able to tolerate a bit more protein than this, and still stay in ketosis.

  14. Even zero-calorie sweeteners may have some negative effects, including maintaining a preference for sweet tastes, and increased reward, potentially increasing the risk of overeating and even food addiction. This is mainly based on clinical experience [weak evidence].

    There is also one RCT study showing weight loss from avoiding artificial sweeteners:

    The American Journal of Clinical Nutrition 2015: Effects on weight loss in adults of replacing diet beverages with water during a hypoenergetic diet: a randomized, 24-wk clinical trial [moderate evidence]

    For more, check out our guide to keto sweeteners or have a look at these further references:

  15. This is mainly based on the consistent experience of experienced practitioners, and stories from people trying different levels of carb restriction [weak evidence].

    There is not yet any RCT that has actually tested two low-carb diets of varying strictness head-to-head. But RCTs of strict low-carb diets appear to often show better results, compared to RCTs of more moderate or liberal low-carb diets.

    This makes logical sense: if something has an effect, doing more of it often has a stronger effect.

    RCTs of low-carb interventions for weight loss

  16. This is mainly based on the consistent experience of experienced practitioners, and stories from people trying different levels of carb restriction [weak evidence].

    There is not yet any RCT that has actually tested two low-carb diets of varying strictness head-to-head. But RCTs of strict low-carb diets appear to often show better results, compared to RCTs of more moderate or liberal low-carb diets.

    This makes logical sense: if something has an effect, doing more of it often has a stronger effect.

    RCTs of low-carb interventions for weight loss

  17. Insulin levels drop significantly on a low-carb diet, as described here: Yes, a low-carb diet greatly lowers your insulin [strong evidence based on consistent results in RCTs, including the following]

    American Journal of Clinical Nutrition 2010: Lack of suppression of circulating free fatty acids and hypercholesterolemia during weight loss on a high-fat, low-carbohydrate diet.

    Nutrition and Metabolism 2006: Comparison of isocaloric very low carbohydrate/high saturated fat and high carbohydrate/low saturated fat diets on body composition and cardiovascular risk.

  18. Low-carb diets reduce feelings of hunger:

    Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]

    Low-carb diets might increase metabolism – potentially increasing fat burning – by between 200 and 500 calories per day:

    British Medical Journal 2018: Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial [moderate evidence] Learn more

  19. Randomized controlled trials, the gold standard of scientific research on diet and health. For example Shai 2008 or Bazzano 2014, and confirmed in several meta-analyses, like Mansoor 2016 [strong evidence].

    Full list of studies with the most important findings explained

  20. Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]

    Obesity 2007: The effects of a low-carbohydrate ketogenic diet and a low-fat diet on mood, hunger, and other self-reported symptoms [moderate evidence]

  21. Here’s a study demonstrating how people tend to eat less on a strict low-carb diet, even without counting calories or trying to restrict food intake:

    AJCN 2008: Effects of a high-protein ketogenic diet on hunger, appetite, and weight loss in obese men feeding ad libitum [moderate evidence]

  22. There’s strong evidence that intermittent fasting can help people lose weight:

    JBI Database of Systematic Reviews and Implementation Reports 2018: Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis [strong evidence]

    Obesity reviews 2017: Short‐term intermittent energy restriction interventions for weight management: a systematic review and meta‐analysis [strong evidence]

  23. This is mainly based on consistent experience from experienced practitioners and a very common report from people trying a keto diet [weak evidence].

  24. There are no high-quality studies, like RCTs, testing this. The support is just consistent experience from experienced clinicians, and a very common story from people testing it [weak evidence].

    Stories about food addiction

    Stories about other eating disorders

  25. The advantage of a low-carb diet has been shown in these reviews of RCTs:

    Diabetes Research and Clinical Practice 2018: Effect of dietary carbohydrate restriction on glycemic control in adults with diabetes: A systematic review and meta-analysis [strong evidence]

    BMJ Open Diabetes Research and Care 2017: Systematic review and meta-analysis of dietary carbohydrate restriction in patients with type 2 diabetes [strong evidence]

    The RCTs include these 3 studies: Daly 2005, Westman 2008 and Tay 2014 [moderate evidence].

    A non-randomized trial with risk of financial bias shows remarkable effectiveness at reversing type 2 diabetes:

    Diabetes Therapy 2018: Effectiveness and safety of a novel care model for the management of type 2 diabetes at 1 year: An open-label, non-randomized, controlled study

    Full list of low-carb studies

  26. A low-carb diet reduces the need of medications for people with type 2 diabetes:

    European Journal of Clinical Nutrition 2017: The interpretation and effect of a low-carbohydrate diet in the management of type 2 diabetes: a systematic review and meta-analysis of randomised controlled trials [strong evidence]

    There’s a controversial but compelling theory that chronically high insulin levels may increase the risk of diseases like obesity, heart disease and several common forms of cancer:

    Insulin toxicity and modern diseases

    Is obesity caused by too much insulin?

  27. There are currently no RCTs testing this hypothesis on this group of people, so the direct support is still only anecdotes and clinical experience. [weak evidence]

  28. A recent systematic review finds that a low-carb diet results in significantly larger improvements in body weight (compared to a low-fat diet) and also improved HDL and triglycerides. LDL went up by, on average, a modest 0.16 mmol/l or 6 mg/dl:

    British Journal of Nutrition 2016: Effects of low-carbohydrate diets v. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials [strong evidence]

    While LDL is fairly marginally elevated on average, there are exceptions. Some people, possibly about 5%, may see significant LDL elevations. While this might not have the same implication as elevated LDL in other circumstances, such as with insulin resistance and small dense LDL particles etc., there is no data to prove this is the case. Here’s our guide to possible ways to reduce this effect:

    Cholesterol levels on a low-carb diet

  29. This has been shown in many studies.

    Diabetes Research and Clinical Practice 2018: Effect of dietary carbohydrate restriction on glycemic control in adults with diabetes: A systematic review and meta-analysis [strong evidence for blood-sugar lowering effect]

    British Journal of Nutrition 2013: Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials [strong evidence for blood-pressure lowering effect etc.]

    Here’s one RCT demonstrating several of these effects:

    Annals of Internal Medicine (Bazzano) 2014: Effects of low-carbohydrate and low-fat diets: a randomized trial [moderate evidence]

    Learn more

  30. This article gives a good background on metabolic syndrome and why low carb may be a good treatment:

    Lipids 2009 (Volek): Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet

  31. This is perhaps interesting for some people, as there are no studies of this duration. But as an anecdote it’s of course very weak evidence.

  32. Here are three fairly typical stories [very weak evidence]:

  33. Learn more in this review article, which has a lot of background information:

    Critical Care 2011: Clinical review: ketones and brain injury

  34. This is something that is often reported by people on a keto diet [very weak evidence].

    The scientific support is not strong. Here are references showing minor signs of improvements:

  35. This is a common experience from experienced practitioners. [weak evidence]

    Here’s a small non-randomized intervention trial that found promising effects:

    Clinical Gastroenterology and Hepatology 2009: A very low-carbohydrate diet improves symptoms and quality of life in diarrhea-predominant irritable bowel syndrome [weak evidence]

    A low-carb diet is generally a low FODMAP diet, and the latter has stronger scientific support for improving IBS symptoms:

    Journal of Gastroenterology and Hepatology 2017: The evidence base for efficacy of the low FODMAP diet in irritable bowel syndrome: is it ready for prime time as a first-line therapy? [moderate evidence]

  36. This is a very common experience for experienced practitioners. [weak evidence]

  37. Athletic performance on a keto diet remains a controversial subject with conflicting data. Issues of adaptation time, type of exercise, differences of training and racing diets, and baseline fitness all play a role in measuring response, and thus the level of evidence is weak. But there are anecdotal reports and case series documenting increased performance for endurance athletics.

    For background and discussions about this potential effect, see these articles:

  38. Here’s a review of the science behind this phenomenon:

    Applied Physiology, Nutrition, and Metabolism 2011: Fat adaptation in well-trained athletes: effects on cell metabolism

  39. Here are a few stories. [very weak evidence]

    How IRONMAN athlete Chris Holley lost 200 lbs

    “I didn’t just beat my best time running on a keto diet – I crushed it”

    Watch the movie Run on Fat

  40. Cochrane Database of Systematic Reviews 2018: Ketogenic diets for drug‐resistant epilepsy [strong evidence]

    Journal of Clinical Neurology 2015: Efficacy of and patient compliance with a ketogenic diet in adults with intractable epilepsy: a meta-analysis [strong evidence]

  41. It’s common for anti-epileptic drugs to have some negative effects on cognition as a side effect:

    Epilepsy & Behavior 2004: Cognitive side effects of antiepileptic drugs

  42. British Journal of Nutrition 2016: Effects of low-carbohydrate diets v. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials. [strong evidence]

    Annals of Internal Medicine 2010: Weight and metabolic outcomes after 2 years on a low-carbohydrate versus low-fat diet [moderate evidence]

  43. American Journal of Clinical Nutrition 2007: A low-glycemic-load diet improves symptoms in acne vulgaris patients: a randomized controlled trial [moderate evidence]

    This review article discusses the theory and the science behind this potential effect:

    Skin Pharmacology and Physiology 2012: Nutrition and acne: therapeutic potential of ketogenic diets

  44. This is a commonly reported positive effect from people who start a ketogenic diet. Here are some stories. [very weak evidence]

    There are two promising early studies so far:

    European Journal of Neurology 2015: Migraine improvement during short lasting ketogenesis: a proof-of-concept study.

    Journal of Headache and Pain 2016: Cortical functional correlates of responsiveness to short-lasting preventive intervention with ketogenic diet in migraine: a multimodal evoked potentials study.

  45. NOTE: This is only an experimental additional treatment of selected cancers, with highly limited evidence. Many conventional cancer treatments (surgery, chemo etc.) are highly effective and they often offer excellent chances of a cure when used in early stages of the disease. To turn down such treatment would be a mistake that could easily be fatal. Also note that the information we provide at DietDoctor.com is not intended to replace consultation with a qualified medical professional. Full disclaimer

    Here are two pilot studies where a ketogenic diet was used in cancer patients. The conclusions are that an insulin-inhibiting diet may be feasible in selected patients with advanced cancer, but there is a lack of clear evidence of a positive effect.

    Journal of Nutrition 2012: Targeting insulin inhibition as a metabolic therapy in advanced cancer [very weak evidence]

    Nutrition & Metabolism 2016: Modified Atkins diet in advanced malignancies – final results of a safety and feasibility trial within the Veterans Affairs Pittsburgh Healthcare System [very weak evidence]

    In brain cancer the ketogenic diet looks like a potentially promising addition to other treatments. This review article describes the theory behind it:

    Frontiers in Molecular Neuroscience 2016: Tumor metabolism, the ketogenic diet and β-hydroxybutyrate: novel approaches to adjuvant brain tumor therapy

  46. A small pilot study of five people with Parkinson’s disease showed an improvement of symptoms on a ketogenic diet. There was no control group, so a placebo effect can’t be ruled out.

    Neurology 2005: Treatment of Parkinson disease with diet-induced hyperketonemia: a feasibility study [very weak evidence]

  47. While success stories generally can’t prove the benefits of a lifestyle intervention, they can add potential value in other ways.

  48. Fiber is digested by bacteria in the colon, and some of it is transformed into a fat called medium-chain triglycerides. This fat can be absorbed by the body and is very effective at turning into ketones. Thus eating more fiber (but still very low carb) could result in higher ketone levels in the blood.

  49. There’s a lack of clear scientific evidence about what level of protein intake that is most beneficial on a keto diet. Quite likely it depends on your goals.

    Here are some thoughts on individualization of protein intake, and details about the views of different low-carb experts.

  50. Here are two guides that may be helpful to you:

    Top 10 ways to eat more fat

    Keto fats and sauces – the best and the worst

  51. How sustainable is the keto diet? It’s not known in detail. But there are a number of studies of ketogenic diets that are at least 2 years in duration. This study looks at children who have been treated with a ketogenic diet for a period of six years or more:

    Developmental Medicine and Child Neurology 2006: Long-term use of the ketogenic diet in the treatment of epilepsy

    Starvation is not sustainable long term, as by definition it implies eating fewer calories than required to maintain life.

  52. This is a common experience from people trying a keto diet [very weak evidence].

  53. Adding extra calories that you don’t need quite likely slows down weight loss. Eating carbohydrates and protein is likely to reduce ketosis, while adding more fat may increase ketosis (but still slow down weight loss).

  54. There’s strong evidence that intermittent fasting can help people lose weight:

    JBI Database of Systematic Reviews and Implementation Reports 2018: Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis [strong evidence]

    Obesity reviews 2017: Short‐term intermittent energy restriction interventions for weight management: a systematic review and meta‐analysis [strong evidence]

    Here’s a review of the scientific support for the theory that intermittent fasting can have other positive health effects:

    Ageing Research Reviews 2017: Impact of intermittent fasting on health and disease processes

  55. The American Journal of Physiology 1986: Response of ketone body metabolism to exercise during transition from postabsorptive to fasted state

  56. Exercise is likely good for health and wellbeing in many ways. It also has some effect on weight loss – but probably a smaller effect than most people expect:

    The American Journal of Medicine 2011: Isolated aerobic exercise and weight loss: a systematic review and meta-analysis of randomized controlled trials [strong evidence for about 1-2 kilos of weight loss]

    Cochrane Database of Systematic Reviews 2006: Exercise for overweight or obesity [strong evidence for about 1-1.5 kilos of weight loss]

    Exercise interventions might be a bit more effective for overweight and obese adolescents (10-19 years of age):

    Sports Medicine 2016: Efficacy of exercise intervention for weight loss in overweight and obese adolescents: meta-analysis and implications [strong evidence for several kilos of weight loss]

  57. This review article summarizes the theory and scientific support:

    Diabetology & Metabolic Syndrome 2015: The impact of sleep disorders on glucose metabolism: endocrine and molecular mechanisms

    Here’s another review article:

    Environmental Health Perspectives 2010: Lose sleep, gain weight: another piece of the obesity puzzle

  58. Here’s a review article on the topic:

    Frontiers in Human Neuroscience 2015: Interactions between sleep habits and self-control

  59. As far as we know there are no high-quality studies (RCTs) that test these supplements and determine their health effects, beyond raising ketone levels. Here is a recent review:

    PeerJ 2018: The use of nutritional supplements to induce ketosis and reduce symptoms associated with keto-induction: a narrative review

    Exogenous ketone supplements do raise ketone levels in the blood:

    Frontiers in Physiology 2017: On the metabolism of exogenous ketones in humans [moderate evidence for raising ketone levels]

    One study of MCT oil for mild cognitive impairment is sometimes mentioned, but it did not show any clear effect. Out of only six participants two quit during the study, one saw some improvement and one got worse:

    BBA Clinical 2015: Pilot feasibility and safety study examining the effect of medium chain triglyceride supplementation in subjects with mild cognitive impairment: A randomized controlled trial [very weak evidence]

  60. As far as we know there is no good reason to believe this to be the case, and no studies to demonstrate it.

  61. An indirect benefit could be possible – if the supplements result in less hunger, they could reduce food intake and potentially aid weight loss. This theory would have to be tested, and as far as we know it has not been tested.

  62. This recommendation is based on positive experience from experienced clinicians. [weak evidence]

    However, there’s also some support from a study that found only minor increases in these side effects, while advising participants to drink bouillon:

    Nutrition & Metabolism 2008: The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus [moderate evidence]

  63. This can sometimes be measured as early as during the first day on a ketogenic diet:

    AJCN 2002: Breath acetone is a reliable indicator of ketosis in adults consuming ketogenic meals

  64. This has been clearly demonstrated in several scientific studies:

    Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]

  65. There’s strong evidence that intermittent fasting can help people lose weight:

    JBI Database of Systematic Reviews and Implementation Reports 2018: Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis [strong evidence]

  66. This is mainly based on a commonly reported experience from people who have tried a ketogenic diet [very weak evidence].

    There’s limited scientific support:

    Appetite 2009: Low-carbohydrate weight-loss diets. Effects on cognition and mood [weak evidence]

  67. At Diet Doctor we show no ads, sell no products and take no money from industry. Neither do we use any affiliate links or profit in any way from the products we mention.

    We’re fully financed by the people, via our optional membership. Learn more

  68. The strips measure for the ketone type acetoacetate. The presence of this in your urine indicates that you’re been in ketosis during the hours before testing.

  69. Breath analyzers measure the ketone acetone.

  70. For example, the Ketonix meter reflects the following levels of acetone:

    • Blue – negative
    • Green – mild ketosis
    • Yellow – moderate ketosis
    • Red – deep ketosis

  71. Blood-ketone meters measure the ketone beta-hydroxybyturate (BHB).

  72. A meter with 10 ketone-test strips and 30 needles included, used to cost about $110 and then an additional $2 per test after that.

  73. The chart is from the excellent book The Art and Science of Low-Carbohydrate Performance by Professor Stephen Phinney and Jeff Volek. Highly recommended.


  74. The levels of the fat-storing hormone insulin will probably be relatively low, as low insulin levels are normally required for ketosis.

  75. The scientific evidence for the mental and physical benefits of this is not strong.

  76. The levels of the fat-storing hormone insulin will probably be very low, as that’s normally required for high ketone levels.

  77. Take insulin, eat carbs (if your blood glucose isn’t already high), and contact medical services immediately.

  78. Other possibilities include doing a strict keto diet while breastfeeding or on a class of diabetes medications called SGLT-2 inhibitors (e.g. Farxiga, Jardiance, Invokana).

  79. It’s often claimed that eating breakfast is good for weight control. That appears to be false:

    The American Journal of Clinical Nutrition 2009: The effectiveness of breakfast recommendations on weight loss: a randomized controlled trial [moderate evidence]

  80. Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]

  81. The fear of saturated fats, like butter, appears to have been completely misguided:

    Nutrition Journal 2017: The effect of replacing saturated fat with mostly n-6 polyunsaturated fat on coronary heart disease: a meta-analysis of randomised controlled trials [strong evidence] (analysis)

    Learn more

  82. A high-carb diet generally leads to higher insulin levels. Insulin causes increased retention of salt and fluid, as described in this article:

    International Journal of Hypertension 2011: Insulin resistance, obesity, hypertension, and renal sodium transport

  83. This piece of advice is based on theory and consistent experience from clinicians using it, and people testing it [weak evidence].

    However, there’s also some support from this study that found only minor increases in these side effects, while advising participants to drink bouillon:

    Nutrition & Metabolism 2008: The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus [moderate evidence]

  84. By far the most common cause is having type 1 diabetes and taking too little insulin.

    In rare cases ketoacidosis may also happen on a keto diet, but normally only when combined with other predisposing factors:

    • Breastfeeding on a ketogenic diet (don’t do a strict keto diet when breastfeeding)
    • Medication with SGLT-2 inhibitors for type 2 diabetes

    Learn more