NEW ORLEANS -- A Harvard obesity expert says he's figured out why diets are failing so many people; it's all about our biology.

He says a new plan can trick biology and cut cravings. It's a radical and different way of looking at weight loss.

Researcher and endocrinologist Dr. David Ludwig says low-fat diets actually work against you. 

"The low fat diet that we've been told to eat for 40 years, has triggered our fat cells to hoard too many calories,"  explained Dr. Ludwig, an endocrinologist at Boston Children's Hospital and Professor of Nutrition at Harvard School of Public Health. "So there are actually too few calories for the rest of the body. We think of obesity as a state of excess, but it's really an issue of starvation."  Ludwug is also the Founding Director of the Optimal Weight for Life program. 

So when the calories are not in the blood stream, the brain thinks we are starving and does its job telling us we are hungry, driving us to seek food, at the same time slowing down metabolism. That means cutting calories only makes it worse. 

"Overeating doesn't make you fat. The process of getting fat makes you overeat, said Dr. Ludwig. 

After two decades of research, Dr. Ludwig says he has the science to help in his book, 'Always Hungry?' He recommends a range of fats from whole foods.

"Fats in the Always Hungry? plan, are like nuts and nut butters, avocado, full fat dairy, chocolate, all these luscious foods that have been banished from our plate for the last 
40 years," Ludwig said. 

The doctor doesn't mean milk chocolate with all the sugar. You can, however, eat very dark chocolate like 80 percent. Phase One, for the first two weeks, takes you away from starch and sugar.

"We eliminate all grains, potatoes, and added sugar, but again it's just two weeks and you won't miss those processed carbs with all these rich, luscious foods," he explains. 
He promises to retrain your fat cells, and cut cravings without deprivation.

"We aim these nutrients to target the fat cells, helping them calm down, putting biology back on your side," said Dr. Ludwig. 

'Always Hungry?' is a three-phase program with recipes that the doctor says directly target fat cells.

You can find more about Dr. Ludwig's findings here.