It's sugar, stupid.
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Gary Taubes
Science journalist, author, and theory maverick

Background
Gary Taubes believed something was missing from the "calories in-calories out" theory in the 1990s, when the former Harvard defensive lineman was watching his diet, working out an hour a day, and still gaining weight. That's when he figured he'd try "this crazy Atkins thing," which melted the weight off and set him on a mission to figure out why. The yield to date: two rigorously argued books, 'Good Calories, Bad Calories' and 'Why We Get Fat,' which challenged the scientific orthodoxy of the obesity epidemic and caused many leading researchers to reconsider the evidence.

Theory
In Taubes' view, the rise in obesity comes from our dietary overload of carbs once the public-health establishment declared fat evil and grains good. It comes down to Adiposity 101: Eating too much sugar stimulates the hormone insulin, while fat and protein do not. Increased insulin triggers hunger and causes calories not immediately burned to be stored as fat. This theory was vindicated by a recent study that found that low-carb, low-sugar diets increase metabolism and weight loss more than low-fat diets with the same number of calories.

Solution
The journalist has joined forces with Dr. Peter Attia to launch the Nutrition Science Initiative nonprofit, which will do the research that Taubes hopes will prove the obesity epidemic comes down to a sugar-insulin cycle. "My dream is that you go to the doctor and he says, 'You're 10, 20 pounds overweight and getting fatter. Boom – don't eat these foods.'"