Slash calories and you will drop pounds. Seems simple, right? Just one problem: Your stomach inevitably stages a protest, rumbling until you give in. The reason, scientists say, is that when your body senses food is in short supply—even if you're restricting it on purpose—it goes on the offense, pumping out more of the hunger hormone ghrelin to coerce you to eat. But just because your gut is biologically anti-diet, it doesn't mean you're doomed to become a bottomless pit. Give these tricks a try, and before long your tummy won't just be quieter—it'll be a whole lot flatter too.
Rise and shine with protein
Nutritionists are always raving about lean protein, and for good reason: It keeps you fuller than other nutrients and takes your body more time to digest and absorb. But what you may not realize is that when you eat it also matters.
A Purdue University study found that eating lean protein (such as Canadian bacon, egg whites, or low-fat yogurt) at breakfast keeps you satisfied longer than if you were to consume it at other times of the day. "Try to get at least one ounce (or 30 grams) of protein at breakfast," recommends Joan Salge Blake, R.D., a clinical associate professor of nutrition at Boston University.
Chow on potatoes
The no-carb craze made spuds out to be dietary villains, but these starches actually have appetite-slaying superpowers. They contain a special type of starch that resists digestive enzymes. Because potatoes take a while to break down, they stay in your intestine longer, delaying the onset of hunger pangs, says Katherine Beals, Ph.D., R.D., a clinical associate professor of nutrition at the University of Utah. Have a baked potato with dinner (a medium spud is only about 100 calories) or better yet, try potato salad made with vinegar instead of fattening mayo; chilling cooked potatoes increases their hunger-busting abilities. Of course, potatoes cooked in a vat of oil (think French fries and chips) are still bad for your bottom line.
Embrace a little fat
Trimming all the fat from your diet can backfire. Oleic acid, an unsaturated fat found in olive oil, nuts, and avocados, helps quash hunger, according to a study in the journal Cell Metabolism. During digestion, it's converted into a compound that indirectly triggers hunger-curbing signals to your brain. Just watch your portions, warns Sari Greaves, R.D., a spokesperson for the American Dietetic Association. Unsaturated fats should make up about 20 percent of your total calorie intake. Greaves suggests snacking on two tablespoons of natural peanut butter, an ounce of nuts, or a quarter of an avocado.
Hitting the gym not only burns calories but also helps you consume fewer of them. A study published in the American Journal of Physiology found that 60 minutes of high-intensity cardio can reduce appetite for up to two hours afterward. "Aerobic exercise lowers ghrelin levels and increases the amount of an appetite-suppressing hormone in your body," says study author David Stensel, Ph.D. To maximize the hunger-dampening effect, make your cardio workout more intense by adding intervals (short bursts of speed with periods of rest in between).
Gobble up grapefruit
Grapefruit diets went out of style with Jane Fonda aerobic videos, but this citrus is staging a comeback. In a study at the Nutrition and Metabolic Research Center at the Scripps Clinic in San Diego, people who ate half a grapefruit with each meal lost an average of 3.6 pounds in three months. According to Ken Fujioka, M.D., the study's principal researcher, these yellow-orange orbs lower your postmeal levels of insulin, the hormone that regulates blood sugar and fat metabolism.
Chew on this
A University of Rhode Island study found that people who chewed gum for one hour in the morning consumed 67 fewer calories at lunch and didn't compensate by eating more later in the day. "One theory is that chewing stimulates nerves in the jaw that are connected to the brain region responsible for satiety," explains study author Kathleen Melanson, Ph.D., R.D., an associate professor of nutrition at the University of Rhode Island. So pop a piece of sugarless—chewing it can keep the munchies at bay and burn 11 calories an hour. (Hey, it's better than nothing!)
Take a whiff
Smelling food can trick your brain into thinking you've eaten. One study found that people who inhaled a peppermint scent every two hours ate 2,700 fewer calories per week than they normally did—that's nearly a one-pound loss! Banana, green apple, and vanilla had similar effects in other studies. And the more often you sniff these aromas, the more weight you'll lose, says Alan Hirsch, M.D., neurological director of the Smell & Taste Treatment and Research Foundation in Chicago. Stash some vanilla-scented candles in your snack drawer or cupboards. And if you tend to eat when stressed, hold your left nostril closed and sniff through the right one to activate the side of your brain where emotions are processed. It could help reduce your anxiety and your appetite.