What makes a keto diet?

Rather than relying on sugar (glucose) that comes from carbohydrates (such as grains, legumes, vegetables, and fruits), the ketogenic diet relies on ketone bodies, a type of fuel that the liver produces from stored fat. Meat and poultry are considered staple foods in the ketogenic diet. The ketogenic diet is a diet high in fat, moderate in protein, and very low in carbohydrates. Carbohydrates are the body's preferred source of energy, but on a strict ketogenic diet, less than 5% of energy intake comes from carbohydrates (learn more in our beginner's guide to the ketogenic diet).

Reducing carbohydrates puts the body in a metabolic state called ketosis. Ketosis occurs when the body begins to break down stored fat into molecules called ketone bodies for use as energy, in the absence of circulating blood sugar from food. Once the body reaches ketosis, most cells will use ketone bodies to generate energy until you start eating carbohydrates again. On a ketogenic diet, you restrict carbohydrates and protein, which means you eat a high-fat diet.

A lack of carbohydrates or protein means you don't have a lot of glucose for fuel. Your body uses that backup fuel, converting the fat you eat and body fat into ketones. The more restrictive your carbohydrate intake (less than 25g of net carbs per day), the faster you'll get into ketosis. There are mixed and paired studies on keto and breastfeeding, though nothing is well-researched right now.

Going back to your old way of eating will undo any of the benefits of the ketogenic diet and maybe even make you gain weight. Although hair loss is very rare on the ketogenic diet, you can minimize it by making sure you don't restrict calories too much and making sure you get 8 hours of sleep a night. In this state, the liver converts fat into small energy molecules called ketones, which the brain and other organs can use for energy. Another study showing a likely connection between high-carb eating and increased acne, so it's likely that the ketogenic diet can help.

It's true that some people on ketogenic diets have experienced adverse effects, including kidney stones and vitamin and mineral deficiencies. At least in the short term, studies show that ketogenic diets achieve surprising and fast weight loss results. If you experience hair loss within five months of starting a ketogenic diet, it's most likely temporary. Scientifically, the ketogenic diet has shown better results compared to low-fat and high-carb diets, even in the long term.

In some cases, increases in LDL cholesterol and LDL particle numbers have occurred in people who eat ketogenic or low-carb diets with less fat and more protein than the classic ketogenic diet. Ketosis is a metabolic state in which the body uses fats and ketones instead of glucose (sugar) as its primary fuel source.