6 Essential Flat-Belly Foods

It's summertime—are you in swimsuit shape?

Even if you've spent the past months dieting yourself into fit form, a few poor food choices each week can quickly add up to a juggernaut of jiggle well before Labor Day. Don't believe us? Consider the caloric damage of typical summer activities—weekly backyard BBQs provide pounds of juicy burgers topped with gobs of high-calorie condiments; ice cream dates offer options of double and triple scoops, smothered in sugar-packed and fat-blasted toppings; and seasonal drink choices (the kind you add umbrellas to and sip from faux-coconuts) guarantee you'll wash it all down with hundreds of extra calories. Not exactly flat-belly fare.

That's why Eat This, Not That! has developed this list of six essential summer foods. The more of these bulge-battlers you eat, the better your chances of keeping those abs flat throughout this skin-baring season.

QUINOA
Per ¼ cup:
170 calories
2.5 g fat
7 g protein
3 g fiber

For starters, anytime you choose a whole-grain product over one made from nutrient-stripped white flour, you wage war against belly fat. Penn State researchers found that dieters who ate whole-grains lost twice as much belly fat as those who stuck to white-flour products—even though they'd consumed the same number of calories. What's more, quinoa contains twice the belly-filling protein as regular cereal grains, fewer glucose-raising carbohydrates, and even a handful of healthy fats. So start your day off with a cup of cooked quinoa combined with a ½ cup of milk and ½ cup of blueberries—microwave for 60 seconds, and you have a delicious (and slimming) alternative to your traditional oatmeal. Bob's Red Mill Organic Quinoa won "Best Grain" in Men's Health's Best Foods Awards 2009.

GREEN TEA
0 calories

Catechins, the powerful antioxidants found in green tea, are known to increase metabolism. A study by Japanese researchers found that participants who consumed 690 milligrams of catechins from green tea daily had significantly lower body mass indexes and smaller waist measurements than those in a control group. It's safe to say that green tea is one of the best beverages for your health—a stark contrast to any of these 20 unhealthiest drinks in America. Avoid those belt-buckling drinks at all costs.

KEFIR
Per cup:
174 calories
2 g fat
14 g protein
3 g fiber

Think of kefir as drinkable yogurt, or an extra-thick, protein-packed smoothie. In either case, this delicious dairy product is a belly-blasting essential. Beyond the satiety-inducing protein, the probiotics in kefir may also speed weight loss. British scientists found that these active organisms boosted the breakdown of fat molecules in mice, preventing the rodents from gaining weight. The researchers still need to prove the finding in humans, but there's no danger in downing probiotic-packed products. We like Lifeway Lowfat Blueberry Kefir—it contains L. casei, the same probiotic used in the study.

AVOCADO
Per avocado:
322 calories
29 g fat (4 g saturated, 20 g monounsaturated)
13 g fiber
4 g protein

Never fear this full-fat Mediterranean-diet staple: It's teeming with healthy monounsaturated fats (also found in olive oil), which have been linked to lowered LDL cholesterol levels and weight loss. In fact, a recent longitudinal study published in The New England Journal of Medicine found that the healthy-fat Mediterranean diet was more effective than a diet that avoided fats altogether—so go ahead and indulge!

EGGS
Per 1 large scrambled egg:
102 calories
7 g fat (2 g saturated)
7 g protein

A British study found that people who increased the percentage of protein-based calories in their diet burned 71 more calories a day (that's 7.4 pounds a year!). Jumpstart your metabolism as soon as you wake up with a protein-rich breakfast of scrambled eggs. (Go to eatthis.com for other great no-diet weight-loss secrets.)

GRAPEFRUIT
Per grapefruit:
104 calories
4 g fiber
2 g protein

A grapefruit a day in addition to your regular meals can speed weight loss. The fruit's acidity slows digestion, meaning it takes longer to move through your system, and you'll end up feeling fuller, and more satisfied, for longer. And the vitamin C-packed grapefruit works to lower cholesterol and decrease risk of stroke, heart disease, and some types of cancer.

By David Zinczenko, with Matt Goulding for Men's Health