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Dr. David Ludwig says cutting calories only makes it harder to lose weight.

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You eat too much, and so you get fat. We all know that. It's not rocket science.

Except it's not actually as simple as that. "Overeating doesn't make you fat," says David Ludwig, an endocrinologist, Harvard Medical School professor and author of "Always Hungry."

So what does make you fat? "The process of getting fat makes you overeat," he says, adding: "Cutting back on calories only makes the situation worse, creating a battle between mind and metabolism that we're destined to lose."

Um ... come again?

Ira Flatow, host and executive producer of PRI's Science Friday, greedily consumed "Always Hungry" before interviewing Dr. Ludwig. He explains the situation succinctly:

"The problem boiled down to my fat cells. You see, fat is not just some gloopy ... blob you're trying to get rid of. It's alive, and releases and responds to chemical signals in the body. It's even looped in with your immune system and can cause inflammation if you do not treat it right. And [Dr. Ludwig's] diet does not count calories. Yay! It lets you eat as much as you want -- once you've retrained your fat cells."

Ah, so there's the catch -- retraining those stubborn fat cells. But Dr. Ludwig insists it's doable for anyone. His is a phased approach that starts with removing processed carbohydrates and some other food categories for a while to make those fat cells start acting differently. He reiterates that the system is not about cutting back on your intake of calories.

"The highly processed carbohydrates we've been eating, and a few other dietary and lifestyle influences, have caused hormonal changes in the body, especially involving insulin that drive fat cells into a feeding frenzy," he says in his interview with Flatow. "So they feast and the rest of the body starves. We think of obesity as a state of excess. But it's really an issue of starvation to the body, and cutting back on calories makes that worse. So instead we propose a much higher fat diet, a three-phase program and some other dietary changes and some lifestyle supports that also help the fat cells calm down. When that happens the calories flood back into the body and you feel much more energetic, cravings decrease, energy expenditure increases. And you start losing weight with your body's cooperation, not against it."

Listen to Flatow's interview with Dr. Ludwig below:

And here's Dr. Ludwig promoting his program in a video: