In a nutshell, it’s a high-fat, extremely low-carb diet with an “adequate” amount of protein thrown in, says Heather Mangieri, a Pittsburgh-based registered dietitian, sports nutrition specialist, and spokeswoman for the Academy of Nutrition and Dietetics.The keto diet isn’t new. Developed in the 1920s to treat drug-resistant epilepsy in children, it’s still used in that capacity today and is being investigated as a potential breakthrough treatment for a range of neurological disorders and diseases. In other words, it’s not just a celebrity weight-loss trend!
What does “ketogenic” mean and how does the diet work?
The aim of the keto diet is to put, and keep, your body in a metabolic state called ketosis.
Our bodies normally burn carbohydrates for energy. When you restrict the amount of carbs, the body will break down stored fat, creating molecules called ketones to use as fuel. (The Paleo diet is similar, but higher in protein and not as strict about certain foods and proportions.)
Ketosis is a normal physiological process. There’s nothing dangerous about it. “It’s just that this particular eating style is keeping your body in that state all the time,” says Mangieri
How low-carb are we talking?
There are various versions of the diet, but generally, we’re talking 75 percent of your daily calories from fat, 20 percent from protein, and 5 percent from carbs.
In real terms, that’s between 30 and 50 grams of carbs a day, says Mangieri. (It requires some intricate calculating based on your body fat percentage to figure out the relevant grams of fat and protein.) In realer terms, 50 grams of carbs is roughly equivalent to 1 1/4 cups of cooked quinoa. Oh, but sorry, you won’t be eating any quinoa on this diet.
So what can I eat on the Keto Diet?
Meat, poultry, and seafood, especially fatty fish like salmon and sardines. Eggs, cheese, butter, cream, and other full-fat dairy. Nuts and seeds. Avocados. Lower-carb vegetables such as greens, tomatoes, onions, and peppers, but in limited amounts. Those carbs add up.
Better-for-you versions of the diet suggest you focus on the so-called good fats—extra-virgin olive oil, grass-fed beef and dairy, and so on—but Mangieri says it’s really anything goes in terms of fats and cooking oils.