You may also have to moderate protein intake somewhat, as high protein intake (greater than 2.0g/kg/d) may make it more difficult to maintain ketosis. However, eating too little protein may also present health issues such as poor muscle development, increased hunger, and lack of essential amino acids. That is why we recommend a moderate level of protein intake, defined as 1.2-1.7g/kg/d. See our protein guide.
Unfortunately, there’s no long-term data on ketogenic diets versus other diets. In a 2015 Italian study, those on a ketosis diet lost 26 pounds in three months. About half of the participants stayed on the diet for a year but lost little additional weight in the next nine months. People in a 2014 Spanish study who followed a very-low-calorie ketogenic diet lost an average of 44 pounds in a year—but a third of them dropped out, possibly because it was too hard to maintain.
Supplemental ketosis: This form of ketosis has recently gained momentum in the field of ketogenic dieting. Supplemental ketosis is a ketogenic state that is achieved through the ingestion of ketogenic supplements. Consuming these substances alone does not mean that an individual is “keto-adapted.” While these products can help during the keto-adaptation period, especially if one is experiencing the “keto-flu,” they will only elicit short-term increases in blood ketone levels. Exogenous ketones can acutely produce benefits similar to the ketogenic diet; however, these products are best used in conjunction with a well-formulated keto diet for beginners, or the very at least, a diet that restricts carbohydrates. The commonly used supplements on the market are medium-chain triglyceride (MCT) oil and exogenous ketones. MCT oil is a fat that, in contrast to other longer-chain fatty acids, travels straight from the intestines to the liver where it is readily metabolized. This allows for ketone production in the liver to occur faster than with other fats (long-chain fatty acids have to travel through the lymph and circulatory systems first). Exogenous ketones are synthetic substances that mimic the ketones produced in our body (endogenous ketones). Exogenous ketones can come in the form of ketone salts or ketone esters.
Yes, they're technically a fruit, but we think olives deserve a shout-out all of their own, since they're also a great source of healthy fats and are one of a few keto-approved packaged foods. Plus, they're a great source of antioxidants, will satisfy your craving for something salty, and are blissfully low-carb. “About a palm's worth only has 3 grams of net carbs,” Sarah Jadin, RD, told Health in a previous interview.
When dietary carbohydrate is broken down into the energy substrate glucose, thereby raising blood glucose levels, the pancreas is stimulated to secrete insulin (the hormone that stores fat and inhibits ketone production). However, when carbohydrate intake is restricted, insulin remains suppressed, and the body’s primary fuel source shifts from glucose to fat, priming the body to enter a state of ketosis. When fat oxidation/breakdown is increased to a certain extent, ketones are made in the liver through a process known as ketogenesis (i.e., keto + genesis = ketone formation). When carbohydrate intake is restricted, blood glucose and insulin levels decrease, which allows fat stores to be broken down rapidly for energy. Most cells in the body can utilize either fatty acids or ketones for fuel, including the brain, which has shown to be more efficient in the presence of ketones rather than glucose.
The ketogenic diet reduces seizure frequency by more than 50% in half of the patients who try it and by more than 90% in a third of patients.[18] Three-quarters of children who respond do so within two weeks, though experts recommend a trial of at least three months before assuming it has been ineffective.[9] Children with refractory epilepsy are more likely to benefit from the ketogenic diet than from trying another anticonvulsant drug.[1] Some evidence indicates that adolescents and adults may also benefit from the diet.[9]
About 20% of children on the ketogenic diet achieve freedom from seizures, and many are able to reduce the use of anticonvulsant drugs or eliminate them altogether.[18] Commonly, at around two years on the diet, or after six months of being seizure-free, the diet may be gradually discontinued over two or three months. This is done by lowering the ketogenic ratio until urinary ketosis is no longer detected, and then lifting all calorie restrictions.[46] This timing and method of discontinuation mimics that of anticonvulsant drug therapy in children, where the child has become seizure-free. When the diet is required to treat certain metabolic diseases, the duration will be longer. The total diet duration is up to the treating ketogenic diet team and parents; durations up to 12 years have been studied and found beneficial.[9]
As mentioned, there are a few reasons why the keto diet usually equals weight-loss gold, says Keatley. For starters, people usually reduce their daily caloric intake to about 1,500 calories a day because healthy fats and lean proteins make you feel fuller sooner—and for a longer period of time. And then there’s the fact that it takes more energy to process and burn fat and protein than carbs, so you're burning slightly more calories than you did before. Over time, this can lead to weight loss.

The classic ketogenic diet is not a balanced diet and only contains tiny portions of fresh fruit and vegetables, fortified cereals, and calcium-rich foods. In particular, the B vitamins, calcium, and vitamin D must be artificially supplemented. This is achieved by taking two sugar-free supplements designed for the patient's age: a multivitamin with minerals and calcium with vitamin D.[18] A typical day of food for a child on a 4:1 ratio, 1,500 kcal (6,300 kJ) ketogenic diet comprises three small meals and three small snacks:[28]


Bonnie J. Brehm, Randy J. Seeley, Stephen R. Daniels, and David A. D’Alessio, “A Randomized Trial Comparing a Very Low Carbohydrate Diet and a Calorie-Restricted Low Fat Diet on Body Weight and Cardiovascular Risk Factors in Healthy Women,” The Journal of Clinical Endocrinology & Metabolism: Vol 88, No 4; January 14, 2009. http://press.endocrine.org/doi/full/10.1210/jc.2002-021480.
On a ketogenic diet, you’re generally eating a diet that’s high in fat (roughly 70 percent of your total calories come from fat), moderate in protein (about 20 percent of your calories), and low in carbohydrate (about 5 percent of calories). By limiting carbohydrates (to usually less than 45 grams for the average person), your body lacks the glucose (from carbs) that it normally uses for energy, so it eventually switches over to burning fat as its primary fuel source instead; through a metabolic process called ketosis, the liver converts the fat into fragments of fatty acids called ketones, which power the brain and other organs and tissues.
Fasting ketosis: Fasting ketosis, also referred to as starvation ketosis, played a major role in the development of the keto diet for beginners. The concept of fasting has been around for centuries and can be traced back to biblical times. By definition, fasting is the absence of caloric consumption for a period of time. This can range from several hours to several days and can have profound effects on the degree of ketosis. As the duration of the fasting increases, so does the production of ketones, and thus a deeper ketogenic state is obtained. As such, the mechanisms of ketone production are similar between fasting and dietary applications similar to keto diet for beginners, both of which result in lower and more stable levels of insulin and blood glucose accompanied by fat metabolism.

There’s also some evidence that it might help with type 2 diabetes. “An emerging body of research is finding that a keto plan may have some real benefits thanks to its ability to improve the body’s ability to use insulin and also help control appetite, which can result in easier weight loss,” says Karen Ansel, R.D.N., co-author of Healthy in a Hurry.


Ready to head out the door and start buying groceries? Slow down there, chief. Go through the pantry, fridge, freezer, and secret stashes under the bed, and get rid of foods with any significant carb content. In the first few days, you could end up craving them—badly. This means fruit, too. Even carrots and onions are too high-glycemic to work with keto, Wittrock says.
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]

Tip: Consuming a moderate dose of exogenous ketones during the initial “keto-adaptation” period could potentially accelerate the “adaptation,” while at a minimum increasing energy production. Once one is adapted, these products are excellent for achieving higher blood-ketone levels, which, in turn, can be beneficial for athletic and cognitive performance, energy production, and perhaps more effective therapeutic treatment.
A simple standby, but one that ketoers adore. 2 or 3 fried eggs and some bacon might not sound like much, but it’s full of protein that will keep you full and energized all morning. Take the opportunity on the weekend to lay your bacon strips on a single cookie sheet and bake in the oven for 20 minutes at 400 degrees. The result is the best bacon you’ve ever had, in a big batch, with no sitting over a popping, hissing frying pan.
×