What to know about the ketogenic diet

— -- The ketogenic diet, described as “Atkins on steroids” for its focus on foods high in fat and protein and low in carbohydrates, is growing in popularity but some nutritionists warn it may not live up to the hype.

The diet’s proponents say that it is the best way to lose weight without feeling hungry and that it increases energy levels. Celebrities including Kim Kardashian and Adriana Lima and athletes from LeBron James to Tim Tebow have all reportedly followed some form of low carb diets.

“Absolutely this diet works,” New York-based registered dietitian nutritionist Maya Feller told ABC News. “It is going to give people weight loss.”

The ketogenic, keto for short, diet was developed in the 1920s after it was noticed that after fasting, epileptics would experience a marked reduction in their seizures. The diet is designed to get your body into a state called ketosis where your body is so low on carbohydrates it starts burning fat for fuel.

Ketosis is also what the body does when fasting.

Keto dieters drastically cut carbohydrates to about 10 percent of their daily diet, which in some cases can be just 20 grams of carbohydrates per day.

That amount of carbohydrates is equivalent to one slice of white bread per day, according to Feller.

Nutritionists also stress that followers of a keto diet should get their fat intake from healthy fats like olive oils and nuts.

Samantha Kafedzic, 31, has lost 17 pounds since starting on a keto diet four weeks ago.

Kafedzic, who admits she now eats “very different” meals from her daughter, said she feels better overall in addition to the weight loss.

“I have more energy with this one running around,” Kafedzic said, pointing to her daughter. “My workouts are so much better. I definitely have more stamina.”

The key to being successful on the keto diet is getting about 20 percent of your calories from protein and eating lots of fat. For some keto followers, the amount of fat could equal more than 70 percent of their diet.

The amount of fat someone following the keto diet may consume in one day could be more than five times the recommended intake for daily fat for the average American, according to Feller.

The diet’s critics argue that it is nearly impossible to follow long-term, could lead to muscle loss and could deprive your brain of its preferred source of fuel, carbohydrates.

Feller agrees that the keto diet is not a diet she would recommend following for an extended period of time.

“The jury is out on if that is safe for the long term,” she said. “What most studies say is that you can follow a ketogenic diet for some months. You don’t want the body to stay in ketosis long term.”

ABC News' Lana Zak contributed to this report.