After following about 121,000 men and women for 20 years, researchers at Harvard University published a study in the New England Journal of Medicine in 2011 that documented the foods and drinks most and least associated with gaining weight. Read on to learn which items should fill dieters' shopping carts--and which should always be avoided.
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Yogurt is a good source of calcium, plus probiotics for gut health. Go for the Greek variety: It boasts all of the benefits of regular yogurt plus double the protein. (Related: Discover what's hiding in your favorite yogurt)
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High water content and key antioxidants and vitamins. (Related: How to Eat Seasonally All Year Long)
Video: The Healthiest Frozen Fruits
"Grains are a great source of protein as well as fiber, vitamins, minerals, and disease-fighting antioxidants," says Brill. "Just make sure the grains you choose are whole, as processed grains lose their fiber, natural vitamins and minerals, and most of their protein." And don't snack on slices of multigrain bread solo and expect to reap the protein benefits of beef. By themselves, most grains, seeds, nuts, and legumes don't contain all nine essential amino acids, says Giancoli. "But if we pair grains with legumes--or legumes with nuts or seeds, that makes a complete protein." Try brown rice and beans, whole wheat couscous with lentils, or hummus made with garbanzo beans and sesame seeds, she suggests.
6 Surprising Ways to Sneak in Whole Grains
Low calorie, lots of vitamins and nutrients, and high fiber.
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Potatoes aren't great for you to begin with; adding salt and deep-frying them strips them of any value they may have had. A typical medium-size portion at a fast-food restaurant contains 410 calories and 18 grams of fat.
When It's Okay to Eat Fried Foods
Potatoes are often fried or covered with butter, sour cream, or sugary ketchup.
How to Make Potatoes Healthier
You may be surprised to learn that in addition to waist-widening sugar and calories, soda contains flame retardants and may fatten up organs.
Try DIY Energy Drinks Instead
Though red meat can be healthy in moderation, the correlation between red meat consumption and weight gain in the Harvard study was undeniable. If you choose to indulge, avoid fatty cuts, such as T-bone, New York strip, and rib-eye steaks.
Healthier Cuts of Meat
Most contain nitrates and are very high in saturated fat. (Related: Best Snacks for Your Diet)