How wide is the divide between the hype and the research? Originally developed to treat severe epilepsy in infants and children under medical supervision, today the ketogenic diet is moving to the mainstream as a low-carbohydrate tool for weight loss and as a means to reduce cardiometabolic risk factors-but not without controversy. Today's Dietitian looks at what the ketogenic diet is, what's known about its risks and benefits, and whether patients who say they're "doing keto" are actually following a ketogenic diet. The ketogenic diet isn't just any low-carbohydrate diet, Supraketo Official and it's not necessarily similar to the Atkins or Paleo diets. The Atkins diet restricts carbohydrates while emphasizing protein and limiting fat, and while the Paleo diet restricts some carbohydrate-rich foods-primarily grains and pulses-it isn't necessarily low carb. The ketogenic diet is very low in carbohydrates and very high in fat, putting the body into ketosis-the burning of fat instead of glucose for fuel.

Essentially, the ketogenic diet promotes a "pseudofasted" state.3 After three to four days of fasting or following a very low-carbohydrate diet, the body, deprived of dietary sugar and starch, reduces insulin secretion and switches to primarily burning fat for fuel. The resulting overproduction of acetyl-CoA leads to formation of ketones-beta-hydroxybutyric acid and acetone-in a process known as ketogenesis.2,4 Whereas the brain can't use fatty acids for fuel, Supraketo for Ketosis ketones can cross the blood-brain barrier, providing fuel to the typically glucose-hungry brain as well as to other tissues. Andres Ayesta, MS, RD, LD, CSCS, CSSD, owner of Vive Nutrition in Orlando, Florida, adding that the true ketogenic diet can have a ratio of 75% to 90% calories from fat, 10% from protein, and 5% from carbs. However, in research and in real life, diets labeled as "ketogenic" vary widely. Diana Reid, MPH, RD, Luxembourg-based owner of The Global Dietitian. Why do ketogenic diets appear to have an advantage for weight loss-at least in the short term, since there are no long-term studies?

There are several potential factors at play-including the fact that with any diet that restricts entire food groups, it's possible that reduced dietary variety leads to reduced calorie intake. Jeff Volek, PhD, RD, a professor in the department of human sciences at Ohio State University. He also points out that some research studies have found that a ketogenic diet has benefits for individuals with type 2 diabetes and prediabetes. Reduction in appetite is a frequently noted effect of the ketogenic diet. This could be because of the satiating effect of protein, despite its restriction to low-to-moderate levels. Or, something about the diet-possibly the ketones themselves-may increase levels of appetite control hormones.4,9 In one small 2013 study of adults without diabetes with BMIs in the overweight or obese range, levels of ghrelin (the hunger hormone) and subjective appetite were lower when the subjects were in ketosis, even on a very low-energy diet (VLED) of 500 to 550 kcal per day.

According to a review published in 2015 in Obesity Reviews, studies have found that individuals adhering to a ketogenic low-carb diet report significantly less hunger and desire to eat compared with baseline, despite moderate calorie restriction and significant weight loss. According to the authors, this may be dependent on circulating ketone levels, but a threshold level had yet to be determined. Research also shows benefits for improving insulin sensitivity and glycemic control, although the mechanisms aren't clear.1 A 12-month study that randomized 34 adults with HbA1c levels above 6% and BMIs above 25 to a very low-carb ketogenic diet or a moderate-carb, calorie-restricted, low-fat diet found that the low-carb group had greater weight loss and reduction of HbA1c. The low-carb subjects also were more likely to be able to reduce use of diabetes medications, with three discontinuing metformin. Studies-most of which compare ketogenic diets with low-fat diets-also have found that while LDL cholesterol tends to increase for some people following a ketogenic diet, small, dense LDLs tend to decrease.1,13,14 Triglyceride and HDL cholesterol levels also tend to improve.