The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control (refractory) epilepsy in children. The diet forces the body to burn fats rather than carbohydrates. Normally, the carbohydrates contained in food are converted into glucose, which is then transported around the body and is particularly important in fueling brain function. However, if little carbohydrate remains in the diet, the liver converts fat into fatty acids and ketone bodies. The ketone bodies pass into the brain and replace glucose as an energy source. An elevated level of ketone bodies in the blood, a state known as ketosis, leads to a reduction in the frequency of epileptic seizures.[1] Around half of children and young people with epilepsy who have tried some form of this diet saw the number of seizures drop by at least half, and the effect persists even after discontinuing the diet.[2] Some evidence indicates that adults with epilepsy may benefit from the diet, and that a less strict regimen, such as a modified Atkins diet, is similarly effective.[1] Potential side effects may include constipation, high cholesterol, growth slowing, acidosis, and kidney stones.[3]
The popular low-carb diets (such as Atkins or Paleo) modify a true keto diet. But they come with the same risks if you overdo it on fats and proteins and lay off the carbs. So why do people follow the diets? "They're everywhere, and people hear anecdotally that they work," McManus says. Theories about short-term low-carb diet success include lower appetite because fat burns slower than carbs. "But again, we don't know about the long term," she says. "And eating a restrictive diet, no matter what the plan, is difficult to sustain. Once you resume a normal diet, the weight will likely return."

It is possible to combine the results of several small studies to produce evidence that is stronger than that available from each study alone—a statistical method known as meta-analysis. One of four such analyses, conducted in 2006, looked at 19 studies on a total of 1,084 patients.[23] It concluded that a third achieved an excellent reduction in seizure frequency and half the patients achieved a good reduction.[18]
Our human ancestors did not consume high-fat, low-carbohydrate diets and therefore would not have been in diet-induced ketosis. Even the most successful early hunters could not possibly have consumed enough fat to enter ketosis since african wildlife such as wildebeests, warthogs and impalas all have low body fat – well under 10%, and as low as 0.3%[6] in the dry season.
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.
Note: Are you a vegetarian or vegan and want to go on a ketogenic diet? It’s still possible! Just keep in mind that the dietary restrictions can sometimes be a little bit intense. Make sure to plan ahead and prepare to aid your success. To help out, we’ve published articles (with 7 day meal plans included) for both the vegetarian ketogenic diet and the vegan ketogenic diet.
There are three essential components of all food: fats, carbohydrates and protein. The ketogenic diet is a carefully prescribed ratio of fats to carbohydrates and protein. This ratio causes the body to convert fat into substances called ketone bodies (thus the name). These ketones are then used for fuel in many cells of the body, including the brain. When this happens, the brain goes into a higher energy state and is better able to protect itself against seizures.
Dr. Campos, it is unfortunate that you retain the medical community’s negative stance on the ketogenic diet, probably picked up in medical school when you studied ketoacidosis, in the midst of an obesity and type II diabetes epidemic that is growing every year, especially among populations who will never see the Harvard Health Letter. The medical community has failed in reversing this trend, especially among children, and the public is picking up the tab, in the form of higher health insurance premiums to treat chronic metabolic diseases which doctors cannot cure. The ketogenic diet does not bid its adherents to eat unhealthy processed meats, and the green leafy vegetables that it emphasizes are important in a number of nutritional deficiencies. People lose weight on the ketogenic diet, they lose their craving for sugar, they feel more satiety, they may become less depressed, their insulin receptors sensitivity is improved, and these are all the good outcomes you fail to mention. There is a growing body of research which demonstrates the neuroprotective effects of the ketogenic diet to slow cancer progression, as well as diseases like Parkinson’s and Alzheimer’s, for which there are no effective medical treatments. Please respect your patients by providing them with evidence-based medical outcomes, not opinions.
Beware of added sugars or high-glycemic sweeteners in spice blends or condiments, but other than that, it’s fair game for keto. In spice-heavy dishes, carbs can add up, but don’t drive yourself crazy worrying about your teaspoon of turmeric. Check labels for additives like sugars, milk solids, potato starch, corn starch, or MSG, or make your own blends at home. Table salt often contains undisclosed fillers and anti-caking agents, so it’s best to opt for sea salt or Himalayan pink salt instead.
No deep fryers or air fryers needed for these wings! Forget those greasy chicken wings you’d order at a restaurant and opt-in for these homemade guiltless garlic parmesan wings. You won’t find rancid vegetable oil, gluten or a deep frier here — just avocado oil, healthy pecorino romano and free-range, organic chicken for a twist on an otherwise unhealthy classic.
The other nutritional remedy for T2 diabetes is carbohydrate restriction. In a large, ongoing university-based study, 60% of patients with Type 2 diabetes reversed their diagnosis of diabetes after just one year on a ketogenic diet, supplemented by support via a mobile phone app.11 On this protocol, 94% of participants reduced or eliminated their need for insulin medications while improving the vast majority of cardiovascular risk factors.12
The ketogenic diet has been studied in at least 14 rodent animal models of seizures. It is protective in many of these models and has a different protection profile than any known anticonvulsant. Conversely, fenofibrate, not used clinically as an antiepileptic, exhibits experimental anticonvulsant properties in adult rats comparable to the ketogenic diet.[58] This, together with studies showing its efficacy in patients who have failed to achieve seizure control on half a dozen drugs, suggests a unique mechanism of action.[56]
Early studies reported high success rates; in one study in 1925, 60% of patients became seizure-free, and another 35% of patients had a 50% reduction in seizure frequency. These studies generally examined a cohort of patients recently treated by the physician (a retrospective study) and selected patients who had successfully maintained the dietary restrictions. However, these studies are difficult to compare to modern trials. One reason is that these older trials suffered from selection bias, as they excluded patients who were unable to start or maintain the diet and thereby selected from patients who would generate better results. In an attempt to control for this bias, modern study design prefers a prospective cohort (the patients in the study are chosen before therapy begins) in which the results are presented for all patients regardless of whether they started or completed the treatment (known as intent-to-treat analysis).[19]
Our human ancestors did not consume high-fat, low-carbohydrate diets and therefore would not have been in diet-induced ketosis. Even the most successful early hunters could not possibly have consumed enough fat to enter ketosis since african wildlife such as wildebeests, warthogs and impalas all have low body fat – well under 10%, and as low as 0.3%[6] in the dry season.
Early studies reported high success rates; in one study in 1925, 60% of patients became seizure-free, and another 35% of patients had a 50% reduction in seizure frequency. These studies generally examined a cohort of patients recently treated by the physician (a retrospective study) and selected patients who had successfully maintained the dietary restrictions. However, these studies are difficult to compare to modern trials. One reason is that these older trials suffered from selection bias, as they excluded patients who were unable to start or maintain the diet and thereby selected from patients who would generate better results. In an attempt to control for this bias, modern study design prefers a prospective cohort (the patients in the study are chosen before therapy begins) in which the results are presented for all patients regardless of whether they started or completed the treatment (known as intent-to-treat analysis).[19]
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. 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.
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