Ketones are a special type of fat that can stimulate the pathways that enhance the growth of new neural networks in the brain. A ketogenic diet is one that is high in fats, and this diet has been a tool of researchers for years, used notably in a 2005 study on Parkinson’s patients finding an improvement in symptoms after just 28 days. The improvements were on par with those made possible via medication and brain surgery. Other research has shown the ketogenic diet to be remarkably effective in treating some forms of epilepsy, and even brain tumors.
"Plenty of people jump right in, thinking all they have to do is cut carbs and increase fat. All of a sudden, they hit a wall and get 'keto flu.' They feel tired, lethargic, and experience headaches," Wittrock says. "The primary reason they get these symptoms is lack of the three primary electrolytes: sodium, potassium, and magnesium. If you're deficient in any of these, you'll suffer mentally and physically. This is the single biggest reason people fail on the keto diet."
When you’re eating the foods that get you there (more on that in a minute), your body can enter a state of ketosis in one to three days, she adds. During the diet, the majority of calories you consume come from fat, with a little protein and very little carbohydrates. Ketosis also happens if you eat a very low-calorie diet — think doctor-supervised, only when medically recommended diets of 600 to 800 total calories.