Intermittent fasting diets "no better" than standard diets for losing weight, doctor says

Science & myths of intermittent fasting diets

Diets that include intermittent fasting are growing in popularity, but one doctor says science doesn't back the trend.

"The bottom line is, it's no better than standard diets in terms of losing weight," Dr. David Agus said Thursday on "CBS This Morning." "It's very hard to comply with. And the clinical trials, more than 40 percent of people dropped out of it. When you look at long-term markers of health it certainly doesn't add up."

The three popular types of intermittent fasting include: "whole day," which means no food at all one or two days a week; "alternate day," which is small meals on specific days of the week and no restrictions on others; and "time-restricted feeding," eating only during a four- to eight-hour window each day.

But according to Agus, regularity is key to a healthy diet.

"The data really show that our body strives for regularity. And so whether you have two meals a day or three meals a day, eating meals with nothing in between is the best thing in the world for losing weight and for health," he said. "So if your friend says, 'Hey, listen, I only want to eat in this eight-hour period and have a lunch and dinner,' that's fine as long as it's regular. The thing is when you eat for five days and skip for two days, that's not regular."

Intermittent fasting: The good, the bad and the hungry

"When you get hungry, that's your insulin going up. And when your insulin goes up and you don't eat, it stays up. And then what happens is you get less sensitive to it. And that's what Type 2 diabetes is. So regular schedule, three meals, nothing, nada, zero, in between – that's the best way to lose weight, have optimal health, and feel good," Agus said.

Last year, MIT biologists found fasting in mice improved their ability to regenerate stem cells. But the fasting studies thus far on humans are not as conclusive. Agus also warned against anecdotal accounts of how one "feels" after fasting diets.

"I can give you a lot of things that make you feel good. I can give you ice cream, you say, it makes me feel good, therefore I should have lots of it. And so how you feel and what is your long-term health aren't always the same. When stress hormones go up, many times you actually feel good, but it's certainly not good for you in the long range."