The 12 Best Diet Foods: Eat more of these foods and loss weigth

Chicken, Beans, and Fish

The Benefit: Women who ate 120 grams of protein a day and exercised regularly lost an average of 21.5 pounds over four months—6.5 more pounds than did exercising women who consumed an equivalent number of calories on a high-carbohydrate diet. The protein group also lost more weight in the abdominal area (while retaining all muscle mass) than the carbohydrate group did, according to a study in the Journal of Nutrition. 

How It Helps You Lose Weight: "Your body has to work harder to digest proteins than it does with carbohydrates and fats, so protein actually burns more calories," says Joy Bauer, registered dietitian and coauthor of Joy Bauer's Food Cures(Rodale Books). "And because it takes a while to digest, it also makes you feel full longer." Eating protein may also signal your stomach to produce less ghrelin, an appetite-stimulating hormone, researchers reported in theJournal of Clinical Endocrinology & Metabolism.

Eggs

The Benefit: Beginning the day with eggs can jump-start weight loss. Volunteers who substantially cut calories from their diets while eating egg breakfasts lost an average of six pounds in eight weeks, versus three and a half pounds for a similarly dieting group who ate equivalent-calorie bagel breakfasts instead. The egg meal consisted of two eggs and two pieces of white toast with reduced-calorie fruit spread; the other breakfast was one bagel, one tablespoon of cream cheese, and less than one serving of fat-free yogurt. The egg eaters also reduced their waist measurements 83 percent more than the bagel group, according to the study at the Pennington Biomedical Research Center of Louisiana State University System.

How It Helps You Lose Weight: The investigators don't yet understand exactly why, but they also found that people who eat eggs instead of a bagel in the morning go on to consume fewer calories over the next 24 hours. "Most of us eat about 60 percent of our daily protein after 6 P.M.," says Donald K. Layman, professor of nutrition at the University of Illinois at Urbana-Champaign. "But you should also have it early in the day so you're less likely to snack later." He recommends as many as 30 grams of protein at breakfast (during which the average American woman gets fewer than ten grams), the perfect time to add some eggs.

Avocado and Olive Oil

The Benefit: Like protein, fat increases satiety, that pleasantly full feeling that signals us to put the fork down. So having a serving of good fat, such as one from avocado or olive oil, can help you feel full. 

How It Helps You Lose Weight: Fat causes the release of certain hormones in the gut that tell your brain you've eaten enough," says Christine L. Pelkman, assistant professor of nutrition at the State University of New York at Buffalo. By slowing the absorption of carbohydrates in the blood, fat also stabilizes blood sugar and, along with it, mood swings that can contribute to cravings and overeating. Get 25 to 35 percent of your calories from fat (for an 1,800-calorie diet, that's 50 to 70 grams a day), the majority of which should be unsaturated—olives and olive oil, nuts, legumes, and fatty fish such as salmon. Good choices include a tablespoon of olive oil (14 grams), a quarter cup of almonds (18 grams), or half an avocado (15 grams).

Wine

The Benefit: In addition to helping your heart, sipping a glass of wine a day may also help a normal-weight woman stay trim. Researchers at Brigham and Women's Hospital in Boston found that participants who drank one or two glasses of wine per day gained fewer pounds than women who drank soft drinks or mineral water. On average, over the 12-year study, women who didn't drink gained eight pounds while those who did gained about three and a half pounds. (Beer and hard liquor tend to be less kind on the figure, so make sure you're raising a glass of wine.)

How It Helps You Lose Weight: One hypothesis is that the livers of those who drink regularly break down alcohol by turning extra energy into heat, not fat. If a woman consumes 120 calories from a glass of wine, the theory goes, most of it will be burned off; but if she eats pizza, more of the calories will morph into fat. Just don't use this as an excuse to get sauced—the weight-gain risk didn't decrease any further when women increased their alcohol consumption beyond that first drink.

Soup

The Benefit: Research has shown that a bowl of soup before a meal can keep your appetite in check. In a study done at Pennsylvania State University, participants ate vegetable soup containing chicken broth, broccoli, potatoes, cauliflower, and carrots. The women who began their lunch with a one-and-a-half-cup portion of it, for about 129 calories, reduced the calorie intake of their entire meal by 20 percent.

How It Helps You Lose Weight: You feel fuller from relatively few calories. You'll want to try this with vegetable-and-chicken soup, since we can't make any guarantees when it comes to broccoli-cheddar.

Grapefruit and Apples

The Benefit: Diets such as Atkins and South Beach dismiss fruit as a "food to avoid," but most experts beg to differ. Fruit consists mostly of water and fiber, so it fills you up without adding a lot of calories. In a six-year study at Laval Hospital Research Centre at Laval University in Quebec, people who increased their fruit intake—whole fruit only, not juice—put on less weight than those who ate little or no fruit. Scientists didn't find the same clear link between vegetables and weight loss, perhaps because they're more easily paired with butter or creamy sauces.

How It Helps You Lose Weight: Grapefruit in particular has long been surrounded by weight-loss mystique, and now there's proof to back up the claims. Volunteers in the study consumed either half a grapefruit or eight ounces of grapefruit juice three times a day, before every meal. After three months, the grapefruit eaters had lost an average of 3.6 pounds and the juice drinkers an average of 3.3 pounds, whereas subjects who drank a placebo juice had lost about half a pound. The researchers speculate that the effect may be attributable to certain chemical properties of grapefruit. If eating all that grapefruit doesn't seem practical, try simply toting an apple to work as a prelunch snack. People who ate about one and a half medium peeled, sliced apples (about 125 calories' worth) 15 minutes before being served a tortellini entree consumed an average of 187 fewer calories from the meal than those who had applesauce, juice, or nothing.

Cereal

The Benefit: Night snackers in a study at Wayne State University in Detroit were asked to eat one cup of unsweetened cold cereal with two thirds of a cup of low-fat milk at least 90 minutes after dinner. (The cereals had 100 to 135 calories, 2 to 6 grams of protein, and 23 to 32 grams of carbohydrates.) After a month, they had shed an average of two pounds—versus less than half a pound for others who continued with their regular snacking habits—and they consumed 100 fewer nighttime calories and 400 fewer calories per day.

How It Helps You Lose Weight: You can have something fulfilling to snack on at night that's not a tray of brownies. But nighttime isn't the only time cereal can help you lose weight; a bowl in the morning can be helpful, too. A study recently published in the American Journal of Clinical Nutritionfound that subjects who ate a high-fiber cereal for breakfast had suppressed appetites, as well as improved glycemic response, after consuming pizza 75 minutes later. High in fiber and low in sugar, Fiber One, Total, Wheaties, and Kashi Go Lean top nutritionists' lists of the best cereals to choose at any hour.