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Intermittent fasting diets: Experts weigh in

May 20, 2013 12:00:00 AM PDT
The biggest trend in dieting right now is not eating for large periods of time followed by eating whatever you want.

Morgan Buehler surfs in the morning and has no problem waiting until lunch to eat.

"I just wake up and exercise and not eat until like 11 or 12 when I felt great," said Buehler.

Buehler lost eight pounds by exercising first and fueling up later. That's one of many on the latest diet trend known as "intermittent fasting."

"I eat dinner at 7 or 8, then normally go like 16 hours before my next meal," said Buehler.

Buehler didn't know it, but she was trying "The 8-Hour Diet," which proposes eating what you want for 8 hours and then fasting for 16, even skipping breakfast. And there are other intermittent fasts.

"One of the popular books out about it now says to eat whatever you want five days a week, and then on the other two days of the week, to go extremely low calories," said dietician Keri Glassman.

Glassman is talking about The Fast Diet and the 5:2 Diet -- both popular in England -- where you eat 500 calories a day, not a meal.

"I don't like the attitude of, 'Oh, eat whatever you want on those other days,' because most people don't control that and aren't able to control that. I really fear that it can set you up for yo-yo dieting," said Glassman.

She's not alone. Nutritionist JJ Virgin says we could all cut our portions, but not like this.

"What they've seen with women who do intermittent fasting is they have poor glucose tolerance," said Virgin. "They don't handle their blood sugar as well, they get insomnia, they get hormone imbalance."

Because hormones play an important role in helping us lose weight, women with high stress levels need to be especially cautious. Dr. Sara Gottried, author of "The Hormone Cure," says stress elevates the hormone cortisol.

"If you have high cortisol and you intermittently fast, it can make your cortisol even worse and pile on your pounds right at your belly," said Gottried.

These experts aren't fans of fasting, but Virgin says if you're going for this diet trend, then skip dinner.

"What are you doing? You're going to bed," she said.


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