ketogenic diet, dietary regime that eliminates or severely limits carbohydrates in favour of proteins and fats as a stimulus for weight loss.
Ketosis is a metabolic condition in which the human body uses ketones, chemical compounds produced by amino acids such as leucine and tyrosine, in place of the glucose that carbohydrates provide in abundance. That condition is historically associated with famine, the body essentially consuming itself in times of food scarcity.
The term ketogenic diet dates to 1930. However, only in more recent decades has the diet, which leverages the consumption of ketones, been broadly publicized and employed as a means for both losing weight and improving diet-related maladies such as type 2 diabetes mellitus. The ketogenic diet has also been shown to have positive effects in the treatment of therapy-resistant epilepsy, Alzheimer disease, and depression, although the mechanisms are not yet well understood.
The ketogenic diet is similar to the Paleo diet, except the latter also bans dairy and soy products and Keto does not. The Paleo diet is based on foods presumed to have been eaten in the Paleolithic Period (Old Stone Age), preceding the origin of agriculture: meat, fish, fruits, vegetables, and nuts but no grains or dairy products. The reasoning behind this diet is that the human body, being slow to evolve, is better suited to this “natural” diet than to the “artificial” one that arrived with the domestication of plants and animals. A typical ketogenic diet is primarily composed of fat (70–80 percent) in the form of meat, fish, lard, butter, nuts, and seeds. The remainder comprises proteins with a very small allowance for carbohydrates. There is no one canonical form of the keto diet, as it is popularly called, save that carbohydrate-dense foods such as pasta, bread, and potatoes are not allowed.
Many doctors are reluctant to recommend the ketogenic diet for several reasons. Because it is fat-heavy, it produces a marked rise in blood cholesterol levels. A secondary effect can be the onset of gout, an ailment associated with a surfeit of proteins and fats and an accompanying rise in levels of uric acid. Also, bread and other carbohydrate-rich foods must be replaced with other food sources of dietary fibre and vitamins. The long-term health effects of the ketogenic diet are not yet well known, but kidney stones and osteoporosis have been noted as possible consequences. Some clinical studies suggest that a ketogenic diet may also lead to higher rates of oncological and cardiovascular disease.
Conversely, medical studies have indicated that a ketogenic diet may be beneficial to those wishing to lose weight who have tried and failed at more-conventional diets. The measurable results are weight reduction, with associated lower levels of blood sugar and blood pressure. Studies suggest that weight loss approaches about 10 percent after one year, no higher than more-conventional higher-carbohydrate diets.