When it comes to influencing fat storage, insulin is the mother of all hormones. Unfortunately, according to Duke University Lifestyle Medicine Clinic Director Eric Westman, MD, as many as two-thirds of Americans are “carbohydrate intolerant,” or insulin resistant, meaning their pancreas produces too much insulin in response to the presence of carbo- hydrates. To lose weight, these people must cut carbs. “This allows the body to reset its insulin response, and without carbohydrates in the equation it has no choice but to burn fat for fuel,” says Westman, author of The New Atkins for a New You (Simon & Schuster, 2010).

Start with a two-week period of sharp carb-cutting—down to 20 net grams per day—recommends Westman. “Net” carbs are total carb grams minus fiber grams, because fiber actually helps balance blood sugar and fill you up. Then slowly ramp up to a maintenance level of 50 to 100 net grams (the younger and more active the person, the higher the amount). Both Teta and Westman recommend loading up on leafy greens and nonstarchy vegetables, such as asparagus, broccoli, string beans, okra, tomatoes, onions, and peppers, while steering clear of high- starch veggies like potatoes, corn, and beans. If you must have starchy produce, Teta recommends literally counting bites: Limit yourself to just 3, or up to 15, depending on how you tolerate carbs. Those who are more sensitive to carbs tend to put on weight around the midsection easily, are more prone to afternoon cravings and mood swings, and often see pounds return quickly as they ramp up carb intake. Keep your fruit intake to two servings a day, emphasizing high-fiber, lower-sugar options like berries, grapefruit, or apples; skip the high-sugar raisins, mangoes, and melons, says Turner.

Are there any no-nos? Blood-sugar- spiking potatoes, fruit juices, and sodas. In a study published in 2011 in the New England Journal of Medicine, Hu found that, of 121,000 U.S. participants, those who gained the most weight over four years were those who consumed the most potatoes and sweetened beverages.