What is a keto diet, and other common questions

Welcome to our keto diet FAQ. These are the most common questions we get, with short and to the point answers. Whenever appropriate we link to a more in-depth guide on the topic, should you want to know more details.

If you have other questions, or if something is unclear, please feel free to leave a comment at the bottom of the page. We’ll keep updating this page and your feedback is helpful.

Frequently asked questions

Click on any question for the answer, or scroll down below for all of them.


 

What is a keto diet?

A keto diet is a low-carb diet that results in . To achieve this, the diet has to be very low in carbohydrates, and no more than moderate in protein.

Usually the diet is also high in dietary fat, at least long term. In a more short-term diet, this is not always necessary. It’s possible to instead be fueled via your own fat stores, as long as you have excess weight to lose.

Learn more about a keto diet
 

What is ketosis?

ketonesKetosis is a normal process allowing your body to keep working when you eat few carbohydrates.

Carbs are one of two major fuels for the body. We can also burn fat for energy, but the brain can’t burn fat directly. Instead, when eating very low carb, fat is converted in the liver to ketones that are released into the blood stream. This is a great fuel for your brain.

The process of fueling the entire body with fat, including the production of ketones, is called ketosis. Under normal circumstances ketosis is safe and natural, for example when it is the result of a low-carb (“keto”) diet, or while fasting.

However, under certain special circumstances – most commonly with type 1 diabetes – ketosis can be a sign of insulin deficiency, and the ketones can then rise to potentially harmful levels.

Learn more about ketosis


 

Is a keto diet safe?

A keto diet is usually very safe. However, in the following three situations you may need extra preparation or adaptation:

If you’re not in one of these situations, you’ll likely do fine on a keto diet, without needing any special modifications.

Note that there’s no shortage of myths and misunderstandings about keto, that frighten children and grownups alike. So if you’re worrying about something in particular, check out this link.

Bottom line: A keto diet is usually very safe. But be aware of the three situations above, i.e. medication for diabetes or blood pressure, or breastfeeding.


 

How do you know when your body is in ketosis?

Symptoms of ketosis: dry mouth, thirst, frequent urination

Any of these signs may indicate you are in ketosis:

  • Decreased appetite and increased energy levels.
  • Increased thirst and urination.1
  • “Keto breath”, which may be more apparent to others than to yourself. Learn more
  • Dry mouth or a metallic taste in your mouth.

Beyond these signs and symptoms, you can measure your level of ketosis, using one of three methods:

Learn more here: How to know you’re in ketosis


 

What foods can you eat on a keto diet?

keto-foods-guide

In summary, eat real low-carb foods like , , , and like butter or olive oil. As a basic beginner’s rule, stick to foods with fewer than 5% carbs (numbers above2).

Full keto diet food list

 

Is a keto diet safe for the kidneys?

Yes. People often wonder about this, because of the belief that a diet high in protein could be harmful for the kidneys. However, this fear is simply based on two misunderstandings:

  1. A keto diet is high in fat, not protein.
  2. People with normal kidney function handle excessive protein just fine.3

Thus, there’s no reason to worry. In fact, a keto diet may even be protective of your kidneys, especially if you have diabetes. Learn more

Bottom line: A keto diet is fine for your kidneys.


 

Is ketosis safe for diabetics?

A keto diet leading to ketosis is generally a very powerful treatment to reverse type 2 diabetes.

People with type 1 diabetes can use a keto or low-carb diet to significantly improve their blood-sugar control. They will however normally always require insulin injections, but usually far lower doses on keto. They need to take care to not take too low doses and end up with ketoacidosis, or too high and end up with keto.

Both people with type 1 and type 2 may rapidly require a reduction in medication on a keto diet to avoid hypoglycemia.

Bottom line: A keto diet can be an excellent choice for people with diabetes, reversing type 2 and control type 1. But it’s very important to adjust medications as needed.


 

What can you drink on the keto diet?

Keto drinks

The quick answer: Water is perfect and zero carb, as are coffee and tea (without sugar, of course). The occasional glass of wine is fine too.

Keto drinks – the best and the worst

Keto alcohol
 

How many carbs can you eat and still be in ketosis?

This varies, but generally it’s a good idea to stay below 20 net carbs per day.

Some people who are not insulin resistant – e.g. lean, young people who exercise regularly – can sometimes tolerate more carbs, perhaps 50 grams or more per day.
 

Is a ketogenic diet safe for high cholesterol?

Generally, the cholesterol profile tends to improve on a keto diet, lowering triglycerides and raising the good HDL cholesterol.

However, a small minority of people may end up with quite high total cholesterol. Whether this is dangerous or safe is debated – there are no quality studies to determine the answer. But should you be one of the few where cholesterol may get up very high, e.g. over 400, you may want to take steps to reduce it just to be safe.

Here’s our guide to elevated cholesterol on keto and low carb.
 

Can you be in ketosis and still not lose weight?

Yes. If so, check out our guide to weight loss.
 

How long does it take to be in ketosis?

It varies, from a day or two, up to a week or more. People with more insulin resistance (e.g. people with type 2 diabetes) usually take longer, while young and lean people generally get into ketosis far more quickly.
 

Can I have fruit on a keto diet?

Fruit on a keto dietAlthough fruits are often considered healthy, they are actually very high in carbs and sugar, unlike non-starchy vegetables. Therefore, when it comes to keto diets, most fruits should be avoided.

However, certain berries are an exception that can be enjoyed in small amounts. The best choices are blackberries, raspberries, and strawberries, which provide 5-6 grams of carb per 100 grams (3½ ounces).

Most other fruits – including blueberries – contain double or triple this amount of carbs, as reflected in this guide to the best and worst fruits in terms of carb content.

Keep in mind that berries don’t provide any nutrients that can’t be found in vegetables and other foods with fewer carbs, so they are entirely optional on a keto diet. In fact, if you are very insulin resistant, you might be better off not having them.
 

How long can someone be on a keto diet?

As long as you want to, and enjoy it.
 

Can I eat a keto diet as a vegetarian or vegan?

A keto diet can work for many non-meat-eaters, depending on what other types of food their diets include.

A lacto-ovo vegetarian eats dairy and eggs, whereas a lacto-vegetarian eats dairy but doesn’t eat eggs. There is also a subset of vegetarians known as pescatarians who include fish in their diet but avoid poultry and other meat.

Although following keto as a vegetarian is definitely doable, it can be a little challenging, especially when first starting out.

Our keto vegetarian meal plan provides several well-balanced, healthy meat-free meals.

On the other hand, a ketogenic vegan diet isn’t a well-balanced or sustainable option. Because vegans exclude all animal products, they must rely on a combination of grains, legumes, and seeds to get all the essential amino acids their bodies need. For this reason, a keto diet and vegan diet don’t work well together. Therefore, you’ll need to make a choice between the two or consider following a keto vegetarian diet, as described above.
 

What should my ketone level be in ketosis?

Generally above 0.5 mmol/l. Learn more
 

What can I do for keto breath?

How to handle keto breath
 

Can I have dairy on keto?

Dairy is nutritious that can be part of a keto diet in many cases. However, whether you personally should eat dairy may depend on your health goals, along with your personal response to it.

For instance, although a higher dairy intake has been linked to fat loss and reduced diabetes risk in several studies, it has also been found to raise insulin levels. Indeed, some people find that cutting back on dairy helps with weight loss.

It’s also important to avoid high-carb options typically considered “healthy,” such as nonfat milk and nonfat yogurt. Instead, focus on these high-fat choices, preferably from naturally raised animals:

  • Butter
  • Cream
  • Sour cream
  • Cream cheese
  • Cheese
  • Plain whole-milk yogurt, Greek yogurt, or kefir


 

Can you build muscle on keto?

Yes.

How to gain weight on keto
 

 

What’s the difference between low-carb and keto diets?

Keto is a very strict low-carb diet, that also puts even more emphasis on moderating the protein intake, and relying primarily on fat to supply energy needs.

A regular strict low-carb diet will likely put most people in ketosis anyway. But a keto diet tweaks things even further to make sure it’s working and, if desired, to get even deeper into ketosis.

Keto could be called an extra strict low-carb diet.
 

Why am I not in ketosis?

The two most common reasons for not getting into ketosis are:

  1. Too many carbs
  2. Too much protein

For more tips see our full guide above. Please note that the amounts that people tolerate while staying in ketosis are individual, differing from person to person. Here’s the first of a 3-part series of blog posts about how our coworker Bjarte Bakke found out how to get into optimal ketosis: Why you’re not in ketosis
 

Should you aim for high ketone levels to speed up weight loss?

Yes and no. Eating fewer carbs, less protein and doing intermittent fasting certainly promotes weight loss, while lowering insulin and raising ketones.

However, adding extra fat to raise ketone levels does not promote weight loss. Neither does supplementing with MCT oil to raise ketone levels, or drinking “exogenous” ketone supplements. These methods actually slow down weight loss, by providing alternative fuel to be used instead of burning body fat.

If you want to lose weight, only use these methods – MCT oil or exogenous ketones – when you are hungry, or for performance reasons (unrelated to weight loss). Learn more
 

At what time of the day should you test ketone levels?

For comparison purposes, it’s good to measure about the same time every day. Measuring in the morning before eating makes it easier to compare the result from day to day.

However, morning numbers are usually among the lowest of the day, while evening numbers are higher. So if for some reason you want impressively high numbers, measure in the evenings instead. Be aware that your ketone levels don’t distinguish between the burning of dietary fat and stored fat.
 

Is keto safe during pregnancy?

A keto diet appears to be safe during pregnancy, judging from the experiences of people who have done it and doctors used to treating patients using a keto diet during pregnancy. It may also be very helpful in case of gestational diabetes.

However, there are no scientific studies on the subject, so there is a lack of definite knowledge. Possibly it’s wise to exercise caution and aim for a more moderate low-carb diet during pregnancy, unless there are important health benefits of doing a keto diet in your specific case. Learn more

Q&A videos

These video titles refer to low carb in general, but they’re equally relevant for a ketogenic low-carb diet.

All Q&A videos

More low-carb questions & answers

More

A ketogenic diet for beginners
14-day keto diet plan

 

  1. Carb restriction and ketosis leads to an increase in excretion of fluids and reduced swelling in the body.

  2. The numbers are grams of digestible carbs per 100 grams, i.e. net carbs.

  3. Here’s an overview of scientific studies on this topic:

    Nutrition & Metabolism 2005: Dietary protein intake and renal function

    Note that people with dramatically reduced kidney function, i.e. people close to needing dialysis, may get instructions from their doctor to reduce protein intake. This advice should of course be followed. However, note that it does not stop that person from doing a keto diet, as the diet is not high in protein in the first place.

18 Comments

  1. Melissa
    Before starting my Keto Diet, I ate a variety of fruits and vegetables. Do you recommend a multi vitamin or supplement to make up for vitamins and minerals that I may be missing?
  2. 1 comment removed
  3. tracy
    i am using centrum vitamins
  4. Denise
    I've consistently run into a few problems / questions as I've (so far unsuccessfully) tried the keto diet:

    1) I get withdrawals from sugar and carbs like a mother! Makes me crazy. I try eating more fat but then feel stuffed. Any ways to soften this experience?

    2) I get the carb flu, badly. Not like I can't function, but bad enough that it's hard to. And I don't know why but the thought of drinking broth makes me want to hurl. Anything else I could do?

    3) I love a morning dry cappuccino breve - that's with half and half. Full fat cream is too heavy for me. Is this okay? Won't pull be out of ketosis?

  5. Laurel
    I see such low numbers of what to expect in terms of weight loss on Keto. It's a fast weight loss plan. Weight Watchers is a slow weight loss plan yielding 2 lbs/week. On this site I saw you suggest that Keto weight loss usually yields 1 lb/week. That's half as fast as a slow program! Something doesn't make sense here.
  6. bryan
    hello my name is bryan iam a 62 yrs young truck driver my probalame is I go to work early and get home late about a 14 hr day . ieat hot oat meal for breakfast, lunch, one sandwhich, chips grapes.apples orange, 2 boiled eggs, and a thermost full of soup this is also my dinner,cant stop because. of time restrats on driving so figure this out and I will try this about 30 lbs over weight
  7. Ulla
    I am allergic to eggs - what can I eat instead for breakfast?
    I also have an under active thyroid and have been told to avoid the crucifers vegetables such as spinach, cabbage, broccoli, etc. Can you give tips how to eat instead?
  8. Anna
    I am hypothyroid, too. I have not been told to avoid cruciferous vegetables, at least not by my doctor! However, I do eat cooked cruciferous vegetables. This is perfectly fine. I need to avoid raw cruciferous vegetables. Also, I am not sure that you need to avoid cruciferous vegetables entirely. Medication will make up for intake of soy and cruciferous vegetables, both raw and cooked. Are you on medication? As for eggs, you don't have to eat eggs! Just eats lots of vegetables instead. It's really good for breakfast. Can add meat to veggies to get some protein and to make you feel full. You don't need eggs.
  9. Lynee
    Is bulletproof coffee recommended during the 2 week challenge?
  10. Beverly
    Browsing recipes, I open one that interests me and I see 3 or 4 stars at the top. Who is it that rates the recipe? It would be more helpful if the rating stars were also shown on the browsed picture/with its name. First week and doing great; thank you.
  11. Ella
    Does anyone ever answer the questions here?
  12. Kathryn
    I am not understanding the "Nutrition" button on the bottom of each recipe. I am trying to figure out the protein and fats in numbers not percentages. Example : the Chicken and green bean recipe says it is 5 carbs. When I try to figure out the proteins I get 48!! That is rather high when I can only have 18 per meal! The fats ends up being 197. Please in order for me to use the recipes on your pages, I need to know how to calculate the actual number not the percentages. Thank you in advance.
  13. Kathie P Djerco
    Can you have fried foods on this diet??? I like deep fried Cod Fish - I know I cannot eat the breading - but can I eat the fish????
  14. Georgia Hicks
    Ella this is for comments only I think. There's a question and answer on another page. Too bad I would like to k ow the answers to some of these questions.
  15. Jennifer G.
    I have a tree but allergy. What can I use in place of nut oils and other tree nut based ingredients?
  16. Linda McDonald
    I've been eating keto diet for 9 months now. Latest blood labs show low HDL level of 95, and LDL of 184! How can this be?! Oh, triglycerides are 40! Thanks!
  17. 1 comment removed
  18. Sophia Darby
    After the 2 week free trails how mush dose it cost for membership? sophiadarby80@gmail.com
  19. Sandra McClelland
    I have CHF and I am not sure if this diet is allright for me.
  20. 1 comment removed
  21. zita
    I Have PCOS can keto diet really help me lose weight like the regular dietaries? or do i have to work twice harder because am already on vegan diet and my weight hast changed as much as i wanted it to be.

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