Ketogenic diet: Is the ultimate low-carb diet good for you?

Marcelo Campos, MD
Marcelo Campos, MD, Contributor

Recently, many of my patients have been asking about a ketogenic diet. Is it safe? Would you recommend it? Despite the recent hype, a ketogenic diet is not something new. In medicine, we have been using it for almost 100 years to treat drug-resistant epilepsy, especially in children. In the 1970s, Dr. Atkins popularized his very-low-carbohydrate diet for weight loss that began with a very strict two-week ketogenic phase. Over the years, other fad diets incorporated a similar approach for weight loss.

What is a ketogenic diet?

In essence, it is a diet that causes the body to release ketones into the bloodstream. Most cells prefer to use blood sugar, which comes from carbohydrates, as the body’s main source of energy. In the absence of circulating blood sugar from food, we start breaking down stored fat into molecules called ketone bodies (the process is called ketosis). Once you reach ketosis, most cells will use ketone bodies to generate energy until we start eating carbohydrates again. The shift, from using circulating glucose to breaking down stored fat as a source of energy, usually happens over two to four days of eating fewer than 20 to 50 grams of carbohydrates per day. Keep in mind that this is a highly individualized process, and some people need a more restricted diet to start producing enough ketones.

Because it lacks carbohydrates, a ketogenic diet is rich in proteins and fats. It typically includes plenty of meats, eggs, processed meats, sausages, cheeses, fish, nuts, butter, oils, seeds, and fibrous vegetables. Because it is so restrictive, it is really hard to follow over the long run. Carbohydrates normally account for at least 50% of the typical American diet. One of the main criticisms of this diet is that many people tend to eat too much protein and poor-quality fats from processed foods, with very few fruits and vegetables. Patients with kidney disease need to be cautious because this diet could worsen their condition. Additionally, some patients may feel a little tired in the beginning, while some may have bad breath, nausea, vomiting, constipation, and sleep problems.

Are there benefits of a ketogenic diet?

We have solid evidence showing that a ketogenic diet reduces seizures in children, sometimes as effectively as medication. Because of these neuroprotective effects, questions have been raised about the possible benefits for other brain disorders such as Parkinson’s, Alzheimer’s, multiple sclerosis, sleep disorders, autism, and even brain cancer. However, there are no human studies to support recommending ketosis to treat these conditions.

Weight loss is the primary reason my patients use the ketogenic diet. Previous research shows good evidence of a faster weight loss when patients go on a ketogenic or very low carbohydrate diet compared to participants on a more traditional low-fat diet, or even a Mediterranean diet. However, that difference in weight loss seems to disappear over time.

A ketogenic diet also has been shown to improve blood sugar control for patients with type 2 diabetes, at least in the short term. There is even more controversy when we consider the effect on cholesterol levels. A few studies show some patients have increase in cholesterol levels in the beginning, only to see cholesterol fall a few months later. However, there is no long-term research analyzing its effects over time on diabetes and high cholesterol.

What’s the bottom line?

A ketogenic diet could be an interesting alternative to treat certain conditions, and may accelerate weight loss. But it is hard to follow and it can be heavy on red meat and other fatty, processed, and salty foods that are notoriously unhealthy. We also do not know much about its long-term effects, probably because it’s so hard to stick with that people can’t eat this way for a long time. It is also important to remember that “yo-yo diets” that lead to rapid weight loss fluctuation are associated with increased mortality. Instead of engaging in the next popular diet that would last only a few weeks to months (for most people that includes a ketogenic diet), try to embrace change that is sustainable over the long term. A balanced, unprocessed diet, rich in very colorful fruits and vegetables, lean meats, fish, whole grains, nuts, seeds, olive oil, and lots of water seems to have the best evidence for a long, healthier, vibrant life.

Related Information: Lose Weight and Keep It Off

Comments:

  1. Lucas Medeiros

    Dr. Campos,

    Your article is very good: best evidence-based medicine, avoided “religious” myths about nutrition, was careful and insightful.

    Hope to read more posts of your thoughtful expertise.

    Congratulations,

    Dr. Lucas Medeiros (from Rio de Janeiro – Brazil)

  2. Robert L. Weiss, L.I.C.S.W., C.A.S.

    I have great respect for Harvard Medical School. I notice that they support their readers posting comments and I am most appreciative of the article and all the many thoughtful comments by the readers. The readers seem to have the most expertise here and I hope that the doctor who wrote the article will think long and hard about the comments by readers. After 35 years of clinical practice in mental health, I notice that all issues of emotion involve medical issues, nutrition, and the gut bacteria. I would say that these issues and all of the executive brain functions seem to improve with ketogenic principles. For those that apply it in a flexible and smart manner, it appears to improve every area of their lives. I strongly encourage the author of the article to take one class via The Institute for Functional Medicine. If he is open to more learning he can take more classes and get certified. I’m sure a fine doctor, he will be an even better doctor and personally healthier, if he gets more training. Are we all open to new learning(especially us healthcare providers)?

  3. Oscar Bressane

    Dear Dr. Marcelo Campos.
    We are brazilian, living in Brazil. My daughter, Isabel, 21y. o., born in 1996, has syndrome of deficiency of Glut1. She was diagnosed around her first year of life. At that time her baby bottle, her begining diet meal, was 50ml water plus 50ml oil plus vitamin. Since then, which means, for 20 years, she is under this diet. For almost 18 years under 4:1 proportion. At this right moment 3:1. The only problem she had since started the diet were kidney stones in 2002. Nothing else. Grateful to the diet she doesn’t take any kind of medicine to avoid seizures. Her health is perfect, no colesterol at all. We are at your will for any issues related to her health.

  4. Max

    Dr. Campos is objective in his presentation, but some of the comments in favor of ketogenic diets are rather exalted in tone. Perhaps a good diet would simply be one where you eat moderate quantities of the basic food groups and exercise a couple of hours a week.

  5. Keenan

    It is a diet that tells you to cut out sugar and starch. So no more doughnuts. Nothing wrong with that!
    Nobody is obliged to consume huge quantities of meat, and meat products. You seem to have a knee jerk bias against this diet because it works, and the usual waffle about “moderation” does not.

  6. Heather

    Keto is not hard to follow at all. See, this is why I took my diet and nutrition into my own hands. I have PCOS and the ketogenic diet has worked wonders for me. I’m finally pregnant at the age of 32 and after 11 years of marriage because the ketogenic diet made me lose over 100 lbs and brought my insulin resistance under control. I feel better than I’ve ever felt. Sometimes doctors don’t seem to know as much as they should, or as much as they assume they do, and that’s pretty disturbing. Just like they’re still using the old school and very inaccurate BMI charts that are just pure bs. I’ll just take care of myself outside of certain situations involving illness or injury. I’m doing great on my own.

  7. Bernard Berger

    Isn’t the Atkins diet the traditional Eskimo diet which Eskimos have eaten for countless generations? Almost nothing grows in Northern Alaska, so the Eskimo diet is almost entirely from meat & fish. Shouldn’t be too hard to study.

  8. bettyG

    Yes you can lose fat on a low carb because it’s just another low calorie diet. How do I know this? I’ve done low carb, (Atkins, etc) high carb, (Slimming Word) moderate carb etc and log my food and was shocked each time to see they were all low calorie. After the initial week or so the rate of fat loss is same as any other diet. It’s calories in calories out. Simple. It’s what some call indirect deficit diet placing silly restriction, rules can eat must eat etc. and of course you lose weight but nothing to do with low carb. It works because it’s a low calorie diet.

  9. Claudia Groposo

    I’m following the ketogenic diet and I find it very easy, pleasant and varied. I can even say that my diet today is more varied than the previous one. I do not intend to leave this diet and I cannot really see why. My initial focus was not to lose weight, I’ve always been lean, but to feel better, well disposed. And I got it! I am very pleased, I have read a lot about it (including scientific literature) and I have influenced other people who need to lose weight or improve some aspects of their health. But from the beginning I went on my own way, without the help of a nutritionist because I did not want to suffer the influence of others’ ideas.

  10. Miriam Kalamian

    Dr. Campos, it is so discouraging to see that you disparage the ketogenic diet based on your assumption that it is very heavy in poor quality processed meats. No diet that relies on processed foods can be viewed as “healthy”. Become better informed by getting up to speed with what Jeff Volek, RD, PhD, calls a “well-formulated ketogenic diet.” Also, learn more about the potential of the diet to slow cancer progression (my specialty). You owe it to your patients who are depending on you for advice. Present them with facts, not opinions.

  11. Anthony

    What about Brain Grain by David Perlmutter.
    Also the Australian CSIRO just published Low-Carb Diet – which is supported by lots of strong evidence. ISBN 978-1-925481-48-8.

  12. Leonora Renda

    While there have not been large studies that show the relationship between the ketogenic diet and cancer, we will be publishing a case study about that topic. The author failed to comment that pediatric patients with epilepsy are on the diet for usually about 2 years with no harmful effects. Before the false studies about heart disease and fat, the low carb diet was a respected way to lose weight. Studies into our metabolism show we can use both fat and carbohydrate as fuel. So stepping away from our high carb diet- I am sorry to say that we eat more carbs since the 70s with most of it processed and we now use high fructose corn syrup to sweeten products and we have a wide spread childhood obesity problem. If cholesterol is a concern try plant sterols and stenals to block cholesterol from the receptors in the body. So much more can be said about a keto diet than this article states

  13. Rita

    There are loads of scientific studies, books, blogs, podcasts etc that provide information about the ketogenic diet. All you have to do is visit the ketogenicforum.com and look for the science section.

    One point not mentioned is that once you are in ketosis hunger and cravings are reduced to the point that even carb addicted people find the diet easier to follow. There are many delicious foods to substitute for your SAD (standard American diet) diet that caused obesity and T2D to become epidemic.

  14. S Z Jafrey

    Would like to know , how safe this diet in diabetics T2, and how long a diabetic can follow this?

  15. Richard

    Despite the scientific evidence pointing to the harm that olive oil and other oils do to the arteries many doctors still repeat the myth. Just more evidence that most doctors are not a good source of nutritional information.
    Even Harvard puts out conflicting information concerning the harmful impact of drinking milk and/or consuming dairy depending on which department at Harvard is putting out the information.

  16. Ted T

    “A balanced, unprocessed diet, rich in very colorful fruits and vegetables, lean meats, fish, whole grains, nuts, seeds, olive oil, and lots of water seems to have the best evidence for a long, healthier, vibrant life.”

    You say a key I diet is very restrictive and hard to follow. Yet, what you recommend, excepting the whole grains, is almost precisely (don’t fear the fat in meat) a keto diet.

    As for the marine’s argument, above, extreme military maneuvers, as do extreme sports, demand their own nutritional requirements that bear no relevance to the average person’s diet (including the typical avid “gym rat”). It is neither fanatical nor unreasonable to eliminate sugars and grains (whole or otherwise) from one’s diet.

  17. Bill Daumen

    I have been on the Keto diet for a year. It is easy to follow and for the first time I feel in contol of my health. Your recommendations on cholesterol and saturated fat need to be updated. Eating high carbs and low fat diets made me hungry all the time. Now I eat 2 meals a day and I’m not hungry.

  18. Joy Jurena

    You may want to become familiar with Dr. Terry Wahls and her version of a ketogenic diet.

    The base of the Wahls diet is above the ground vegetables. Far more than in a vegan diet. She doesn’t do dairy or eggs as she is sensitive to both. Further, she consumes mostly coconut oil as her primary fat – for the ketones and this allows for higher intake of vegetables and some fruit. The only vegetable oil is olive.

    She is very strict about adhering to her protocol and one can understand this . She reversed secondary progress MS.

    I do not know if I am in ketosis but I do the daily fast of 12-16 hours, drink homemade bone broth and use only the fat she recommends. I have no chronic conditions but did get rid of arthritic pain and have terrific lipid numbers.

  19. Anoush Aleksanyan

    Thanks for this inputs. 20 years ago I gain 17 pounds a year for 5 years. I was healthy but my dr told me start diet, any diet just come back in a month I want to see you start loosing… I started Atkins and lost 7 pound in a month. She was checking my progress every six months and checking my condition. I lost 64 pounds in 3 years. Now I started eating out of control. I am eating healthy but too much… I gain 40 pound back after 20 years. Now I will start again my Atkins to take off 30 pounds…

  20. Thomas T

    .. it can be heavy on red meat and other fatty, processed, and salty foods that are notoriously unhealthy. What is unhealthy about red meat. We should know that acrilamides, pyrroles in burnt meat (and veges) from BBQ and over-heated cooking inflames the colon. According to Clark H R, PhD ND an inflamed part allows easy entry for the cancer nucleus and cancer complex, to start and fuel a malignancy at that location.

    Fatty bad? Grass fed animal fats have CLA, LCFAs and Om3, all heart healthy. Cholesterol is essential for life, for stress and sex hormones, for Vit A and D synthesis etc.

  21. WOODRUFF W HALSEY II

    Would love to hear more about ketosis as a way to fight cancer. Is it true that cancer cells feed on sugar, but not ketones?
    Woody Halsey

  22. Frank LeFever

    I think monosaturated fats should be emphasized — such as is found in peanut butter and olive oil. N o need to make a peanut butter sandwich — no bread needed, just eat it by the spoonful.
    I have also read a study that reports blood levels of PUFAs rise adequately only if these valuable fats [especially valuable omega-3] are ingested with lecithin. I hold lecithin granules in my mouth while I chew on capsules of fish oil.

  23. Melissa

    I actually went on a ketogenic diet last year to see if it would help my migraines. I have a history of chronic migraines which would usually last 3 days, sometimes longer. Triptans help a lot but I don’t like having to take them. I stayed in ketosis for about 8 months and experienced a significant reduction in migraines, from feeling some type of headache (mild o r severe) almost everyday to 1 or 2x per month while in ketosis. Although I’m very healthy otherwise, I do think my migraines may have something to do with blood sugar fluctuations (despite previously eating a whole foods diet and no refined carbs), and keto totally stabilized this. I eventually came off of Keto because I’m not really a meat lover. When I came off, but remained low carb, my migraines stayed under control for the most part. When I increase carbs, they do return.

    • Beth

      I actually clicked on the story just to see if they included anything about it’s use in managing chronic migraine. I have chronic migraine, basically intractable. Nothing has helped. I’ve tried medications, meditations, and everything in between including a bunch of dietary changes. Keto is my next consideration. I’m happy to hear it helped you! Thanks for sharing

    • Frank LeFever

      Very interesting. My classical migraines transitioned to “migraine equivalents” 20 years ago, but I believe migrainous disturbances go far beyond headaches — migrainous confusion, etc. and these may be persisting, accounting for such things as my balance problems, etc.

  24. bill reichert

    No one knows the long term effects of the ketogenic diet and they never will know because it is impossible to study diet
    scientifically over a long time (i.e over 2o years)
    .

    • Richard

      No idea how you came to that conclusion but it simply is not true.
      You can dispute the traditional Okinawan diet if you like but the facts are there for everyone that knows how to read.
      There have been many cases of large populations consuming almost identical diets for many decades, not just Okinawa.

  25. Harley Hill

    Interesting article regarding a diet I followed in the 70s with great success. A favor, please. Could you please correct the mispelling of “outweighs. ” (You spelled it “outways,” and it grates. ) Thank you.

  26. Romilly Hodges

    Thank you for bringing needed attention to this topic.

    A ketogenic diet is in our toolkit of dietary and lifestyle interventions that we have seen very helpful for numerous conditions, including weight loss, insulin/glucose dysregulation, neurological disorders, even cancer. We often use it during a period of more intense therapeutic intervention, not as a maintenance diet.

    It is not a high-protein diet, however. It is a high-fat diet. Attention needs to be paid to food quality, types of fat intake, and micronutrient intake, just like any other diet.

    Increases in cholesterol levels need discussion too. We do see temporary increases in cholesterol levels often as individuals transition onto a ketogenic diet. However, when you examine lipid particle size (a more important way to look at the cardiovascular risks), the risk pattern doesn’t seem to increase with a ketogenic diet. Harvard Health has written about lipid particle size here before: http://www.health.harvard.edu/womens-health/should-you-seek-advanced-cholesterol-testing-

    Although four years old now, this is a nice review of the literature on ketogenic diets for various health conditions: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3826507/
    Another, more recent review (not free text), here: https://www.ncbi.nlm.nih.gov/pubmed/26782788

    Romilly Hodges MS CNS
    Director, Nutrition Programs for Dr. Kara Fitzgerald

  27. Paulo A Franke

    Shameful to see a fellow countryman joining the anti-fat, pro-grains stupid Harvard bandwagon.
    But then, what should I expect?
    Brazilians are happily following the idiotic obesity example of Americans, indulging in sugars and cereals. And getting obese and sick by doing it.
    Shame on Brazil, shame on the US of A.

  28. cheryl

    This was a great read. I aim to restrict carbs always because I believe most are why the American population is obese. I would very much like to hear more about carb restriction excluding the discussion on processed meats and processed high salt content foods because I consume neither. I also don’t consume dairy or eggs. So can you provide some substance.

  29. Nigel

    Another point is protein intake. It needs to be 1g per 1kg of weight, not as this article suggests.

    Too much protein can knock you out of ketosis.

    I’m now 3 months ketogenic.

    Loce it!

  30. John Wright

    There is nothing inherently difficult about following a ketogenic diet. We have many patients who do this very easily over many years. The metabolic benefits significantly outway any perceived challenges from limiting particular food types. Uptake would be far more widespread if nutrition professionals left their predujical opinions of SFA’s behind. Finally, given the expertise in Ketogenic Diets at Harvard, Dr David Ludwig, for one springs to mind, I am surprised the author did not avail themselves of the local expertise.

    • eric

      Very well put! I’m in full agreement. I also noted the author’s ignorance in suggesting a 2-4 day time-line in the shift to fat-adaptation. Sure, ketones may show up in the bloodstream soon enough, but certainly not full nutritional ketosis in that short of time. I found that to be telling.

  31. Macrofour

    Thanks Dr Campos,

    We do need more discussion of the keto diet. That said:

    I have been on a low carb keto diet for more than a year. As T2DM my A1C dropped from 9% to 5.4% & I discontinued meds. All my lipids improved even with ample healthy saturated fat. More than a year now so I wonder why this would be a short term improvement when its obvious that I will not go back to a high A1C and taking 3 diabetes medications including sulphonylureas. It is clear from this article that you lack the necessary experience that would be gained from wholeheartedly trying the diet or monitoring patients doing it properly like me. I would be probably be facing my first amputation if I believed the negativity in your article. So for people with diabetes who may be dissuaded by your article. Ignore it and take back your health by restricting carbs (<25 g a day) or as low as you reasonably can below 130g while being satisfied that you are getting adequate nutrition.

    Macro Four

    • Michael Souza

      You’re but one of many fanatics I’ve observed whose minds contract once they happen on something “new and miraculous.” The good doctor is sharing his bit of wisdom; if you don’t agree, it’s wiser to keep your fanaticism in check, lest you come across as a mindless jihadi.

      I was a Corpsman (not a corpse-man as some recent somewhat fanatical president would say), and I can tell you many stories of Marines and Sailors who maintained restrictive diets (aka picky eaters). Most obvious was lack of sustaining energy (hypoglycemia) at mile 15 (with 80lbs of gear including a 6.5lb rifle and 200 rnds of ammo, etc.) and depletion of essential vitamins, electrolyte imbalance. They were always the first to collapse and have to hear me scold “see I told you so.” An IV of D5W usually does the trick (D is for dextrose, OMG!)

      Look, the good doctor is right – he only forgot to stress “portion control” which is why many fanatical dieters are so kee-jerk reactive to any discussion – odds are you over ate like a hog before your keto diet, and are weak and insecure in your diet plans. Eat EVERYTHING in small amounts, and you will live long and prosper. The only thing to avoid are processed foods. Cook your meals from scratch using quality ingredients.

      • Helen

        Fanatic? Someone with T2D, a disease usually claimed to be progressive and a never ending stream of problems and medications, was REVERSED. That’s something to shout from the rooftops. The drop in medication use alone, but the big pharma companies would prefer that people’s stories of reversing (well, putting it into remission) T2D get called fanatical instead of insightful.

        The poster isn’t weak and insecure — he was probably following the food pyramid that tells people to eat five (5!) meals a day, and to load each and everyone up with carbs.

        Keto and LCHF have tremendous health benefits, in particular for people who have overeaten themselves into metabolic diseases.

  32. Othman

    Hello,
    i am Personal Trainer and own a gym, and i tried along with our dietionist this diet plus 5 days weekly training on 4 clients to be honest we’ve got a huge amazing result, one of my clients went from 149kg to 82kg in 9 months…
    But we used mixed diets, Ketogenic diet was for 1 month and it wasn’t difficult due to the nature of our region (Mediterranean), but we used also some supplementation to protect the body cells and also some other supplementation like the BCAA during the training sessions…
    I guess Ketogenic diet is a must especially for the First month, than you can change the diet and training also is a must.

  33. Jonah

    Thanks for this article. I just started a Keto diet so found it appropriate to my current lifestyle. Though I don’t believe your bottom line is strong enough since you simply stating that the diet is “hard to follow” and food is “notoriously unhealthy” without evidence going deeper into why those “notoriously unhealthy” foods are worse than keeping carbohydrate-heavy food that are addictive and give the body a quick sugar high for energy. I believe “hard to follow” is your opinion only, since acceptable Keto foods are found at all restaurants easily and also all grocery stores. All the foods you mention: “rich in very colorful fruits and vegetables, lean meats, fish, whole grains, nuts, seeds, olive oil, and lots of water” are all Keto-friendly. Many people have been on a Keto-diet for years. A healthy lifestyle is a healthy mindset change and making right choices – it’s not going to be easy.

  34. Keegan

    A great read! Thank you for the thorough explanation of ketogenic dieting. For me this just reinforces the obvious; a healthy balanced diet is the best approach to obtaining and maintaining a healthy body. Moderation is key.

    I love my carbohydrates!

    Hope to see more posts from you Dr. Campos!

    • Frank LeFever

      Very interesting. My classical migraines transitioned to “migraine equivalents” 20 years ago, but I believe migrainous disturbances go far beyond headaches — migrainous confusion, etc. and these may be persisting, accounting for such things as my balance problems, etc.

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