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Fasting: The Key To Quick, Healthy Weight Loss?

MINNEAPOLIS (WCCO) - The Movement Minneapolis, a hardcore gym known for intense workouts, is a noisy place at lunchtime. But owner David Dellanave says after the workouts, not much is spoken about lunch.

"If you're not hungry, why are you eating?" Dellanave said.

Members like Lacy Morgan and Martin Rittenbery skip eating once or twice a week.

"I've heard them preaching about it, so I decided to give it a go," Morgan said.

They're doing something called intermittent fasting.

"It's almost a personal self-cleanse. I quick cleanse," Rittenbery said.

It's a diet idea that Dellanave says has one simple rule.

"You just eat everything you normally would, but you don't eat anything one or two days a week," he said.

There are various versions, including Lean Gains, Eat, Stop, Eat and a version that became popular in Britain called the 5:2 diet.

"If you want to lose body fat, you might want to be hungry so that your body can switch over to the snacks stored around your waist," Dellanave said.

Some plans allow a few hundred calories on fast days.

"For me it was just a good exercise to kind of feel comfortable with hunger, not let food, you know, control me," Morgan said.

However, some plans only allow water or zero-calorie drinks on those two days.

"Depending on the relationship with food, it can be pretty tough," Rittenbery said.

KDWB's Dave Ryan has been doing the 5:2 diet, which lets him eat 600 calories on his fast days.

"I'm like a lot of people. I just want to lose weight and I'm frustrated because I'll lose five pounds, and I'll gain back six," Ryan said.

He read the book in one day and lost six pounds in the first week. Dave says he's doing it with his wife, and it actually has them eating better the rest of the week.

"Would I love to have a bacon cheeseburger pizza at any time? Oh, absolutely. But it's not unbearable to eat just 600 calories twice a week," he said. "On those off days, you feel like 'yeah, I still kind of want to have a salad rather than the meatball sub.'"

The math makes sense. If you fast on two days and don't gorge yourself on the other five, your calorie count has to be lower. But what about the other claims about how fasting allows organs to rest, improves metabolism and increases the body's sensitivity to insulin?

Carrie Peterson is a dietitian at the University of Minnesota, and she also advises the Vikings, Twins, Timberwolves and the Wild. She's doubtful of the claims in favor of intermittent fasting.

"Well, the science behind this, they're using some mice studies," Peterson said. "In terms of insulin tolerance, I think it probably has to do more with eating well rather than taking an entire day off from eating, and allowing your pancreas to rest so that you're not getting any insulin spikes," Peterson said.

Still, Dellanave says he's seen client after client lose weight over the last four years. And much like the caveman diet - where you eat protein, protein, protein - the 5:2 plan is easier to sell to men than traditional diets.

"It's simpler, and guys don't like to follow rules," Dellanave said.

Nicole LaVoi studies gender at the U of M's Tucker Center. She says men and women do view diet differently: many women crave structure and restrictions, while men prefer simpler, more tangible milestones.

"I think it maybe resonates more with men because it's maybe more of an all or nothing," La Voi said. "It's a short amount of time and it's minimal sacrifice."

Everybody agrees that it's a tough way to eat long-term. At Movement Minneapolis, Dellanave says people who used it to get down to their goal weight go back on it for short spurts whenever they need to lose a few more pounds.

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