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A low-carb diet for beginners
, medical review by Dr. Bret Scher, MD
Evidence basedStudies show that low-carb diets result in weight loss and improved health markers.1 These diets have been in common use for decades and are recommended by many doctors.2 Best yet, there’s usually no need to count calories or use special products – all you need to do is to eat real food.3
Learn more about low carb and how to use it for your personal goals here.
1. What is low carb?
A low-carb diet means that you eat fewer carbohydrates and a higher proportion of fat. This can also be called a low-carb, high-fat diet (LCHF) or a keto diet.4
For decades we’ve been told that fat is detrimental to our health. Meanwhile low-fat “diet” products, often full of sugar, have flooded supermarket shelves. This has most likely been a major mistake, that coincided with the start of the obesity epidemic.5
Studies now show that there’s no reason to fear natural fats.6 Fat is your friend (here’s why). On a low-carb diet, you can eat all the fat you need to feel satisfied and, instead, you minimize your intake of sugar and starches. Most people can eat delicious foods until they are satisfied – and still lose weight.7
How does it work? When you avoid sugar and starches, your blood sugar tends to stabilize and the levels of the fat-storing hormone insulin drop.8 This increases fat burning and makes you feel more satiated, reducing food intake and causing weight loss.9
Studies show that a low-carb diet can make it easier to lose weight and to control your blood sugar, among other benefits.10
The basics
- Eat: Meat, fish, eggs, vegetables growing above ground and natural fats (like butter).
- Avoid: Sugar and starchy foods (like bread, pasta, rice, beans and potatoes).
Eat when you’re hungry, until you’re satisfied. It can be that simple. You do not need to count calories or weigh your food.11 And just forget about industrially produced low-fat products.12
Below are examples of what you could eat, alternatively check out our 700+ low-carb recipes.
Who should NOT do a strict low-carb diet?
Most people can safely start a low-carb diet.13 But in these three situations you may need some preparation or adaptation:
- Are you taking medication for diabetes, e.g. insulin? Learn more
- Are you taking medication for high blood pressure? Learn more
- Are you currently breastfeeding? Learn more
If you’re not in any of these groups, you’re good to go!
This guide is written for adults with health issues, including obesity, that could benefit from a low-carb diet.
Controversial topics related to a low-carb diet, and our take on them, include saturated fats, cholesterol, whole grains, red meat and restricting calories for weight loss.
Getting started fast
Do you want to get going with low carb right away? Make it truly simple by signing up for our free two-week low-carb challenge. Or get unlimited meal plans, shopping lists and much else with a free membership trial.
In 60 seconds
Does low carb still seem complicated? Check out our visual low-carb in 60 seconds guide
2. What to eat on a low-carb diet
In this section you can learn exactly what to eat on low carb, whether you prefer visual guides, detailed food lists, delicious recipes or a simple get started guide.
Let’s start with a quick visual guide to low carb. Here are the basic food groups you can eat all you like of, until you’re satisfied:
The numbers above are grams of digestible carbs per 100 grams (3.5 ounces). Fiber is not counted, you can eat all the fiber you want.14
All foods above are below 5% carbs. Sticking to these foods will make it relatively easy to stay on a strict low-carb diet, with less than 20 grams of carbs per day.
Try to avoid
Here’s what you should not eat on low carb – foods full of sugar and starch. These foods are much higher in carbs.
The numbers are grams of digestible carbs per 100 grams (3.5 ounces), unless otherwise noted.
Detailed list of foods to avoid
What to drink
What drinks are good on a low-carb diet? Water is perfect, and so is coffee or tea. Preferably use no sweeteners.15 A modest amount of milk or cream is OK in coffee or tea (but beware of caffe latte!).16
The occasional glass of wine is fine too.
For more, check out our complete guides to low-carb drinks and low-carb alcohol.
Visual low-carb guides
Here are more detailed visual guides to the amount of carbs in common foods. Is a specific food item low or high in carbs? Click to find out:
Vegetables 
Fruits 
Nuts 
Snacks 
Alcohol 
Fats & sauces 
Drinks 
How many carbs? 
Sweeteners
Recipes
Browse our over 700 delicious low-carb recipes or head over to our 14-day low-carb meal plan for inspiration. You can always find our recipes under “Recipes” in the top menu. Here are a few popular ones:
Meals
Breakfasts
Snacks
Desserts
Bread
All low-carb recipesMeal plans
Here’s an example meal plan:
Mon
Tue
Wed
Thu
Fri
Sat
Sun
Check out the meal-planner tool
How low carb is a low-carb diet?
The fewer carbohydrates you eat, the more powerful the effects on weight and blood sugar appear to be.17 For that reason we recommend initially following the dietary advice fairly strictly. When you’re happy with your weight and health, you may carefully try eating more carbs (if you want to).
Here are three examples of what a low-carb meal can look like, depending on how many carbs you plan to eat per day:
Ketogenic 0-20 
Moderate 20-50 
Liberal 50-100
A strict low-carb diet is often called a ketogenic (or “keto”) diet.
Video course
Here’s an 11-minute video course on how to eat low carb, high fat. Sign up for our free newsletter18 for instant access to it:
Get started
Keen to get started? Then sign up for our free 2-week low-carb challenge, where you’ll be guided step-by-step through your low-carb journey.
Leaflet
Here’s a leaflet with basic low-carb advice, that you may want to print and have around, or give to friends who are curious:
Low-carb advice in 40 languages
We have written advice on a low-carb diet in 40 languages, including our full Diet Doctor site in Spanish or Swedish.
3. Potential benefits of a low-carb diet
Why would you consider eating fewer carbs? There are many potential benefits, proven by science and supported by clinical experience, like these:
Lose weight
Most people start eating fewer carbs to lose weight. Studies has shown that low-carb diets are often more effective than other diets.19 Low carb makes it easier to lose weight without hunger, and without having to count calories.20
According to new science, a low-carb diet can even result in burning more calories than other diets.21 Learn more
However, the reason many people keep eating low carb is often the powerful health effects, like the following ones.
Reverse type 2 diabetes
Low-carb diets can help reduce or even normalize blood sugar, and thus potentially reverse type 2 diabetes.22
Low carb can also be helpful in managing type 1 diabetes.23
A grateful gut
Low carb might help settle a grumpy gut, often reducing symptoms of irritable bowel syndrome such a bloating, gas, diarrhea, cramps and pain.24 Indigestion, reflux and other digestive issues can sometimes improve, too.25
For some, this is the best part of going low carb and happens usually within the first few days, or first week, of starting the diet.26 Learn more
Reduce sugar cravings
Are you struggling to stay away from sweet foods, even though you try to eat them in “moderation”? Many people do.27
A low-carb diet can often reduce and sometimes even eliminate cravings for sweets 28
Bonus benefits
Weight loss, shrinking fat stores, lower blood sugar, improved mental clarity, and a calmer digestive system are the most frequently cited benefits of low-carb eating.29
But some people experience even more improvements, some of which can be life-changing: lower blood pressure,30 less acne and better skin,31 fewer migraines,32 possibly improved mental health symptoms, better fertility,33 and more.34
The links below share more inspiring testimonials and scientific research about potential low-carb benefits.
Blood pressure 
Acne 
Physical endurance 
Epilepsy
Heartburn 
PCOS 
Migraine 
Alzheimer’s Success stories
We’ve been sent over 600 amazing low-carb success stories, and get more all the time. Here are a few, and links to all of them sorted by categories:
Eight years of zero-carb eating and "have never looked or felt better!"
A low-carb diet: Maintaining a 70-pound weight loss for five years
Low carb and me – my journey as a GP
Women 0-39 
Women 40+ 
Men 0-39 
Men 40+ 
4. Low-carb tips and guides
To make a low-carb diet truly simple and enjoyable requires a few new skills. For example, how do you cook low-carb breakfasts that you love? How do you eat more healthy fats? And what’s important to think about when dining out?
Here are all the guides you need.
Breakfast
Breakfast is a great time to eat low carb. Who doesn’t love bacon and eggs? In the unlikely event that you answered “I”, there are even great options with no eggs at all.
Another strong option is to just have a cup of coffee, as many people get less hungry on a low-carb, high-fat diet and may not need breakfast at all.35 This can save you plenty of time.
There are many other options – both delicious and fast
Meals
So, what’s for lunch and dinner on a low-carb diet? You could for example have meat, fish or chicken dishes with vegetables and a rich full-fat sauce. There are a million alternatives.
Check out our recipes to learn to cook amazing low-carb meals
Instead of potatoes, pasta and rice
Who needs starchy sides when you can have cauliflower mash or cauliflower rice instead? Not to mention butter-fried green cabbage, yum!
In short, there are lots of great low-carb alternatives to carb-rich foods that are both tasty and healthy
Eating out
It’s very possible to eat low carb even when leaving your house, for example at restaurants. Just avoid starchy foods and ask for some extra natural fat (e.g. olive oil or butter).
This guide helps you with tips for fast food, other restaurants, buffets and for when you eat at a friend’s house
Snacks
You probably don’t need to snack as much on a low-carb diet, as you’ll likely feel satisfied longer.36
However, if you want something right away you could have cheese, nuts, cold cuts or even an egg. There are lots of amazing options
Bread
Do you have a hard time living without bread?
There are good and bad low-carb options. Spoiler: you’ll probably want to stay away from “low-carb” bread from the grocery store! Here’s why, and what to do instead
How to eat more fat
Fat can be both satiating and an amazing flavor enhancer. But how do you get in enough of it in your diet? And how much fat should you really eat? Hint: enough to feel satisfied and not hungry.
Learn all about it in this guide
Avoid “low-carb” junk food
Many who are eating a low-carb diet can get seduced by creatively marketed “low carb” products — cakes, cookies, candies, chocolate, pastas, breads, ice cream and other substitute foods.
Unfortunately this rarely ends well, especially not for weight loss. These products are usually junk food, and often much higher in carbs than their labels try to imply. Preferably avoid. Learn more
How to make low carb cheap
A low-carb diet doesn’t have to be expensive. In this guide, you’ll learn how to make it cheap.
With a little planning and preparation you could save a ton of money
Low-carb cheating
Is it a good thing to occasionally cheat on a low-carb diet? That depends. And it’s worth thinking about what’s right for you. Learn more
More guides
Do you want more low-carb guides? We have more low-carb guides!
All low-carb guidesTop videos about low-carb basics
Here are some of our hundreds of low-carb videos:
5. Potential side effects on a low-carb diet
If you stop eating sugar and starch cold turkey (recommended) you may experience some side effects as your body adjusts. For some people these side effects are mild, while others find the transition more difficult. It usually lasts a few days, up to about a week, and there are ways to minimize it.
Another option is to decrease the intake of carbohydrates slowly, over a few weeks, to minimize side effects. But the “Nike way” (Just Do It) may be the best choice for most people. Removing most sugar and starch often results in several pounds lost on the scale within a few days. This may be mostly fluids, but it can still be great for motivation.
Here are side effects that may occur when you suddenly start a strict low-carb diet.
Induction flu
By far the most common side effect is called the induction flu. It’s what makes some people feel really poorly for a few days (up to a week) after starting low carb.
Here are common symptoms:
- Headache
- Fatigue
- Dizziness
- Nausea
- Irritability
These side effects rapidly subside as your body adapts and your fat burning increases. Within a week, they are usually gone.
The primary reason for this may be that carbohydrate-rich foods can increase water retention in your body.37 When you stop eating high-carb foods you’ll lose excess water through your kidneys. This can result in dehydration and a lack of salt during the first week, before the body has adapted, resulting in the symptoms above.
You can minimize the induction flu by drinking more fluids and by at least temporarily increasing your salt intake. A good option is to drink a cup of bouillon/broth one or two times a day. This usually keeps the induction flu minor or even non-existant.38
Alternatively, drink a few extra glasses of water and put more salt on your food.
Learn more about induction flu and how to treat it
Other common issues on low carb
Beyond the induction flu, there are six more relatively common side effects on a low-carb diet. It seems like many of them can also be mostly avoided by getting enough fluid and salt.39
There are also more things you can do to minimize any problems, click to read more if you’ve experienced one of these issues:
Leg cramps 
Constipation 
Bad breath 
Heart palpitations 
Reduced physical performance 
Reduced tolerance to alcohol
Less common issues
These are less commonly noticed issues, that generally only affect a minority of people:
Potential danger when breastfeeding 
Gallstone problems 
Temporary hair loss 
Elevated cholesterol 
Keto rash 
Gout All low-carb side effects and how to cure them
Low-carb controversies
Beyond the mostly transient side effects that may occur on a low-carb diet (see above) there are many controversies, misunderstandings and a few pure myths that simply don’t hold up to closer scrutiny. For example, your brain is supposed to stop working unless you eat carbs. We’ll, that’s simply wrong.40
Read all about these topics on our low-carb controversies page, or choose a specific topic below:
Brain 
Ketoacidosis 
Gut bacteria 
Deficiencies 
Thyroid 
Kidneys 
Depression 
Osteoporosis 
Saturated fat 
Cholesterol 
Environment
6. Learn more
Here’s the sixth and final section of this low-carb page. Do you want to truly understand low carb, and get answers to your remaining questions? Or do you want extra inspiration for yourself or for people you’re trying to help?
Find it here, and start becoming a low-carb expert.
Low-carb TV
Get insight, enjoyment and inspiration to help you succeed, from the top low-carb channel on the planet.
Select from hundreds of awesome videos, and we’re adding 2-4 more new ones every week. Enjoy! The service is only available for members, but we offer a free trial. Join free for a month
How low carb works
What are you designed to eat, and why can sugar and starch be a problem? Essentially, how does a low-carb diet work?
Scientific studies on low carb
Questions and answers
Are you having problems on low carb? Are you not losing weight like you want to? How many carbs should you eat?
Get answers to your low-carb questions
Why fat is your friend
A lot of people still fear natural fat. But really, the whole idea that we should fear fat is based on a scientific mistake, and many open-minded experts now admit it.41
Just witness the recent TIME cover to the right, with the text “Eat Butter. Scientists labelled fat the enemy. Why they were wrong.”
Learn more about cholesterol and why fat is your friend
Upcoming low-carb events
Do you want to learn much more, and meet experts and other people who are interested in low carb? Here’s a current list of upcoming low-carb conferences and other events.
The Food Revolution
Do you want a summary of the ongoing food revolution? From failed low-fat diets and an epidemic of obesity and diabetes, through a growing realization of our mistakes, and towards a potential health revolution.
Watch this talk by Dr. Andreas Eenfeldt, the founder of Diet Doctor:
Next
You’ve reached the end of this page (congratulations!). Keep reading about what to eat on a low-carb diet
More
Don’t miss
Low-carb foods 
14-day low-carb diet meal plan
Scientific studies now prove that compared to other diets, low carb is generally more effective, for weight loss and certain health markers:
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 of the top studies showing more weight loss and improvements in health markers on low carb:
- New England Journal of Medicine 2008: Weight loss with a low-carbohydrate, mediterranean, or low-fat diet [moderate evidence]
- Annals of Internal Medicine 2014: Effects of low-carbohydrate and low-fat diets: a randomized trial [moderate evidence]
For many more studies on the topic, have a look at our low-carb science page.
Hundreds of success stories: Low-carb success stories ↩
While calories count, you probably don’t have to count them for good results. Low-carb diets tend to result in more weight loss, even though most studies of it do not advocate counting calories:
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 for more weight loss]
The reason could be that people’s appetite tends to be somewhat suppressed on low-carb diets, so that people can eat fewer calories and still be satisfied:
Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]
Another potential cause may be that under some circumstances people tend to burn more calories on a low-carb diet:
British Medical Journal 2018: Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial [moderate evidence]
Learn more here: Should you count calories on a low-carb or keto diet? ↩
A keto diet is a common name for a very strict low-carb diet, containing very few carbohydrates, generally below 20 grams per day. This usually results in a metabolic state called “ketosis”, hence the name.
A low-carb diet is always relatively low in carbohydrates. But not necessarily so low that people end up in ketosis. Here at Diet Doctor we consider anything up to 100 grams of carbohydrates per day a low-carb diet. ↩
While this is still controversial, repeated modern systematic reviews find no benefit from avoiding saturated fats, or replacing them with unsaturated fats:
- Open Heart 2016: Evidence from randomised controlled trials does not support current dietary fat guidelines: a systematic review and meta-analysis [strong evidence]
- 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]
Further modern reviews on related topics:
Annals of Internal Medicine 2016: Association of dietary, circulating, and supplement fatty acids with coronary risk: a systematic review and meta-analysis [strong evidence for lack of obvious health effects of emphasizing “fat quality”]
PLOS ONE 2016: Is butter back? A systematic review and meta-analysis of butter consumption and risk of cardiovascular disease, diabetes, and total mortality [strong evidence for a lack of major health issues related to butter consumption]
Learn more about why low-fat diets may have been a major mistake ↩
Open Heart 2016: Evidence from randomised controlled trials does not support current dietary fat guidelines: a systematic review and meta-analysis [strong evidence]
Low-carb diets tend to result in more weight loss, even though most studies of it do not advocate counting calories:
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 for more weight loss]
The reason could be that people’s appetite tends to be somewhat suppressed on low-carb diets, so that people can eat fewer calories and still be satisfied:
Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]
Another potential cause may be that under some circumstances people tend to burn more calories on a low-carb diet:
British Medical Journal 2018: Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial [moderate evidence] ↩
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]
Low-carb diets tend to result in more weight loss than other diets:
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 for more weight loss]
Increased satiety and reduced hunger:
Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]
Increased fat burning:
British Medical Journal 2018: Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial [moderate evidence]
Our weight is hormonally regulated. Eating fewer carbohydrates lowers blood glucose, lowering the fat-storing hormone insulin. This often makes it way easier to access and burn excess body fat, without hunger or calorie counting.
PLOS ONE 2015: Dietary intervention for overweight and obese adults: comparison of low-carbohydrate and low-fat diets. A meta-analysis [strong evidence]
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]
While calories count, you probably don’t have to count them for good results. This has been demonstrated in studies (see below).
Learn more here: Should you count calories on a low-carb or keto diet?
Low-carb diets tend to result in more weight loss, even though most studies of it do not advocate counting calories:
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 for more weight loss]
The reason could be that people’s appetite tends to be somewhat suppressed on low-carb diets, so that people can eat fewer calories and still be satisfied:
Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]
Another potential cause may be that under some circumstances people tend to burn more calories on a low-carb diet:
British Medical Journal 2018: Effects of a low carbohydrate diet on energy expenditure during weight loss maintenance: randomized trial [moderate evidence] ↩
Besides not helping prevent heart disease (see references above, including this one) there are many reasons to avoid low-fat products:
The low-fat diet: “a massive public health failure”
The problem with low-fat products
Journal of the American Medical Association 2016: Lowering the bar on the low-fat diet ↩
The main fear about low-carb, higher-fat diets has been potentially increasing the risk of heart disease. But modern studies do not support that theory, and many risk factors even improve on low carb:
- 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 for improved risk factors]
- Obesity reviews 2012: Systematic review and meta‐analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors [strong evidence for improved risk factors]
- Circulation 2010: Dietary intervention to reverse carotid atherosclerosis [moderate evidence for a reduction in atherosclerosis]
Fiber does not directly affect blood sugar levels, though it can indirectly slow down the absorption of digestible carbohydrates that you eat.
Fiber can have both beneficial and some potential negative effects on gut health, but it usually has no major impact on the effects of a low-carb diet. ↩
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 one RCT 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 low-carb sweeteners or have a look at these further references:
- International Journal of Obesity 2017: Effects of aspartame-, monk fruit-, stevia- and sucrose-sweetened beverages on postprandial glucose, insulin and energy intake
- Physiology & Behavior 2016: Recent studies of the effects of sugars on brain systems involved in energy balance and reward: relevance to low calorie sweeteners
- PLOS Medicine 2017: Artificially sweetened beverages and the response to the global obesity crisis
Also avoid other coffee drinks with lots of added milk or sugar. ↩
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 an RCT that test 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.
Our weekly newsletter gives you the top low-carb news, recipes and tips without ads or industry influence. Your email is kept 100% private. To cancel press “unsubscribe” at the bottom of any newsletter. ↩
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 for more weight loss] ↩
Scientific studies now prove that compared to other diets, low-carb or keto diets are often more effective for weight loss (even when many of the studies do not recommend counting calories):
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 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 ↩
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]
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 [weak evidence]
There is still a shortage of high-quality studies, but what exists is promising, sometimes showing remarkable improvements.
PLOS ONE 2018: Low-carbohydrate diets for type 1 diabetes mellitus: A systematic review [strong evidence for promising early results, but a shortage of high-quality RCTs]
Pediatrics 2018: Management of type 1 diabetes with a very low–carbohydrate diet [very weak evidence for an exceptionally strong positive effect]
Asia Pacific Journal of Clinical Nutrition 2016: A randomised trial of the feasibility of a low carbohydrate diet vs standard carbohydrate counting in adults with type 1 diabetes taking body weight into account [moderate evidence for a positive effect, though a very small study]
This is a common experience from experienced practitioners. [weak evidence]
This small non-randomized intervention trial show 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 a low FODMAP diet, and the latter has 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] ↩
Digestive Diseases and Sciences 2006: A very low-carbohydrate diet improves gastroesophageal reflux and its symptoms. [weak evidence]
Alimentary Pharmacology and Therapeutics 2016: Dietary carbohydrate intake, insulin resistance and gastro‐oesophageal reflux disease: a pilot study in European‐ and African‐American obese women [weak evidence]
This is a very common experience for experienced practitioners. [weak evidence] ↩
Like anything else that can be highly rewarding – gambling, drugs, etc. – sweet processed foods can result in addiction issues. Note that it’s likely not just a specific substance – e.g. sugar – that is the culprit leading to addiction, but rather the full rewarding experience of certain foods, e.g. sweet chocolate.
Here are a few papers discussing this issue.
Neuroscience & Biobehavioral Reviews 2008: Evidence for sugar addiction: behavioral and neurochemical effects of intermittent, excessive sugar intake
↩This is likely mostly caused by avoiding the foods that can cause a food addiction, most of which are processed foods full of sugar and/or other refined carbohydrates.
Just like with any other addiction, avoiding the cause is a necessary part of slowly reducing the addiction. A person who is addicted to alcohol normally can’t consume alcohol “in moderation” and be successful. The same thing is likely true for any addiction.
In the case of low-carb diets, it may also be that the hunger-reducing effect can be helpful:
Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence] ↩
Most of these potential benefits have strong or moderate scientific support (see references higher up on the page).
Regarding mental clarity, this is something that is often reported by people on a strict low-carb diet [very weak evidence].
The scientific support for increased mental clarity is not strong. Here are references showing minor signs of improvements:
- European Journal of Clinical Nutrition 2013: Ketosis and appetite-mediating nutrients and hormones after weight loss
- Appetite 2009: Low-carbohydrate weight-loss diets. Effects on cognition and mood
- Neurobiology of Aging 2012: Dietary ketosis enhances memory in mild cognitive impairment [moderate evidence for verbal memory improvement in people with early Alzheimer’s]
- Epilepsy Research 2012: The effects of the ketogenic diet on behavior and cognition
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] ↩
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 ↩
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:
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. ↩
Nutrients 2017: The effect of low carbohydrate diets on fertility hormones and outcomes in overweight and obese women: a systematic review [strong evidence]
There is likely a positive effect of low-carb diets on PCOS, a common hormonal problem for women that can impact fertility.
European Journal of Clinical Nutrition 2013: Beyond weight loss: a review of the therapeutic uses of very-low-carbohydrate (ketogenic) diets ↩
Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]
Contrary to older misconceptions, a recent meta-analysis of randomized clinical trials found that people assigned to skip breakfast ate less overall and lost more weight than those assigned to eat breakfast daily:
British Medical Journal 2019: Effect of breakfast on weight and energy intake: systematic review and meta-analysis of randomised controlled trials [strong evidence] ↩
This is a very common experience from people trying a low-carb diet, and it’s supported by science:
Obesity Reviews 2014: Do ketogenic diets really suppress appetite? A systematic review and meta-analysis [strong evidence]
The appetite-reducing effect might be partially mediated by certain hormonal factors:
European Journal of Clinical Nutrition 2013: Ketosis and appetite-mediating nutrients and hormones after weight loss ↩
International Journal of Hypertension 2011: Insulin resistance, obesity, hypertension, and renal sodium transport ↩
This is mainly based on the consistent experience of experienced clinicians [weak evidence]. But there’s also some support from this study that found only minor increases in 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] ↩
E.g. one or two cups of bouillon per day.
The evidence for this is mainly based on the consistent experience of experienced clinicians [weak evidence]. But there’s also some support from this study that found only minor increases in 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] ↩
On a strict low-carb diet, the liver produces ketones from fat, that become an effective fuel for the brain. Learn more about it in this overview article:
Critical Care 2011: Clinical review: ketones and brain injury
↩Open Heart 2016: Evidence from randomised controlled trials does not support current dietary fat guidelines: a systematic review and meta-analysis [strong evidence]
Learn more about why low-fat diets may have been a major mistake ↩