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Feast or Famine: Evidence Mounts for Fasting Diets

Eat all your favorite foods and still lose weight? Seems almost too good to be true.

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Jennifer Stewart, 54, with husband meal prepping in kitchen. NBC News /
Jennifer Stewart, 54, with husband meal prepping in kitchen. NBC News /
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There is Growing Evidence That Fasting Diets Really Work

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Eat all your favorite foods and still lose weight? Seems almost too good to be true, but for Jennifer Stewart it’s been the answer to a life-long battle with being overweight.

“I lose weight very slowly and don’t lose weight like normal people,” says Stewart. “I had tried all kinds of diets. I went to a nutritionist in my late teens. I would lose like a half a pound a week and it didn't quite make sense.”

But then, about two years ago, Stewart, 54, discovered intermittent fasting, a method of dieting that has gained popularity over the last decade.

For Stewart, here’s how she started: Every other day she would eat no more than 500 calories and on the days in between, called her "feast" days, she consumed about 2,200 calories.

And unlike other weight loss plans that usually restrict refined carbs, fat, or sugar, Stewart eats whatever she wants on her feast days.

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Jennifer Stewart, 54, with husband meal prepping in kitchen.

“I still get in 100 grams of protein (on the feast day) which for me is important and on the fast day I would eat almost all non-carb foods because that helps curtail cravings,” says Stewart.

It's a diet that was originally criticized by the medical community, but now is gathering scientific backing.

In Phase 1 of the plan, which lasted about 18 months, Stewart lost 110 pounds. Krista Varady, associate professor of nutrition at the University of Illinois at Chicago, has extensively researched alternate-day fasting. In one study of 700 people, she found they were typically unable to binge on their feast day. Instead, they tend to only eat about 10 percent more than they usually would.

“In terms of weight loss, we found people lose in general about 10 to 30 pounds in eight weeks,” said Varady. “People also tend to see reductions in bad cholesterol, triglycerides, blood pressure.”

However, her research shows alternate day fasting is not for everyone. 10 percent of the people in her study dropped out in the first 10 days.

And another report in The American Journal of Clinical Nutrition found for women, that alternate-day fasting could decrease glucose tolerance and potentially disrupt their metabolism.

Stewart is now on a maintenance plan. For her that’s, 1000 calories on fasting days, 2,000 on feast days. It has helped her lose an additional 20 pounds, and gain confidence.

“I feel content, that's how I feel,” says Stewart. “I don't feel like I've arrived because I was always the fattest person in the room. I had the biggest rear end in the room. Now I don't have the biggest rear end in the room and I think that's a wonderful accomplishment.”

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