The Secret Battle of the Bulge

From conquering cravings to revving metabolism, hormones are the key to zapping flab. Here's how to use them to your advantage

Get Chemically Balanced

Image: Dan Hallman/Getty Images

Hormones are responsible for more than just the occasional binge. Their ebb and flow in your body control nearly every aspect of your weight, from when you get hungry to where you're most likely to store flab. Even fat cells themselves secrete multiple hormones. (Search: How do hormones affect weight?)

Something else you may not know: You can make these powerful chemicals work for you. "People have a lot more sway over their hormones than they think they do," says Lena Edwards, M.D., director of the Balance Health and Wellness Center in Lexington, Kentucky. These strategies will help you take charge over five of the most influential.

Hormone: Leptin

One of the many hormones produced by your fat cells is leptin, which plays a role in appetite control. Research has found that excess body fat can cause a condition known as leptin resistance, which means your brain isn't affected by leptin even though your body contains higher levels of it. Though it's still unknown exactly why this occurs, one theory is that as fat cells crank out inflammatory chemicals that block the action of leptin, your body begins to think it's starving. Obviously, that's not really the case, but to compensate for this perceived threat to survival, your metabolism slows down and your brain sends constant hunger signals in an effort to force you to eat, especially high-calorie foods.

Balance It Out: The good news is that leptin resistance can be combated with diet and exercise. One thing that could help: Try eating one cup of vegetables before 10 a.m. each day. Scott Isaacs, M.D., an endocrinologist in Atlanta and the author of Beat Overeating Now! Take Control of Your Hunger Hormones to Lose Weight Fast, has found that people who take this advice tend to be less hungry later in the day. Plus, along with satiating fiber, vegetables contain essential antioxidants and vitamins that have been shown to reduce the inflammation that interferes with leptin, which in turn helps increase fat burning and reduce your cravings

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Hormones: Cortisol and Serotonin

Ever wonder why a hectic day sends you diving face-first into a bag of chips? That's the result of your adrenal glands releasing the stress hormone cortisol. That response, which is meant to give you a burst of energy for fighting or fleeing, can often remain high due to sustained stress, leaving you craving high-sugar or high-carb foods. There's even some evidence that cortisol causes you to accumulate fat specifically in your belly. Serotonin has the opposite effect: It calms you down and is a natural appetite suppressant. In fact, the newest FDA-approved drug for weight loss, Belviq, works by boosting the activity of serotonin in the brain. (Related: The 13 Best Foods for Your Brain)

Balance Them Out: To get the same effect without drugs or sugary high-cal carbs, load up on folate-rich lentils, asparagus, and spinach. Your brain uses the B vitamins in these foods to make serotonin. Getting enough sleep helps too; a study in the Journal of Clinical Neurology found that cortisol levels can double after a single all-nighter. (Are you feeling frazzled? Pull out your yoga mat and try this Stress-Conquering, Body-Toning Yoga Routine.)

Hormone: Insulin

Every time you down a carb-laden meal or sugary drink that makes your blood sugar skyrocket, your body responds by releasing insulin, whose job it is to pull extra glucose (sugar) from the bloodstream. Overdo it on pasta, bread, or sweets, and insulin can cause those excess calories to be stored as fat, says Edwards. In some cases, extra pounds can lead to insulin resistance, a condition in which cells become less responsive to the hormone, and to diabetes.

Balance It Out: You can control the amount of insulin your body produces and how well your cells respond to it by cutting back on foods that cause the biggest spikes in blood sugar. According to a study in Circulation, soft drinks account for a full third of the added sugars in our diets, so nixing them is a great start. Then trade processed, refined carbs like white pasta and bread for whole-grain versions, which contain fiber to slow the absorption of sugar into the bloodstream, making for a more even-keeled insulin response. (Bonus: The fiber will also help you feel fuller for fewer calories.) Spacing out your meals and snacks so that you're eating smaller portions at more frequent intervals throughout the day is another smart way to maintain consistent levels of glucose and insulin, says Edwards. (Need a portable snack option? Try one of The 6 Best Energy Bars for Women.)

Hormone: Irisin

Last year, a study in the journal Nature announced the discovery of a way to make white fat—the kind we all know and hate—behave more like brown fat, a kind that actually burns calories. The key is exposure to a newly discovered hormone dubbed irisin, which is produced by muscle tissue and released during exercise. The hormone also appears to help reduce insulin resistance.

Balance It Out: Getting your sweat on is the number one way to ramp up irisin levels and, in turn, produce more fat-burning brown fat. In the Nature study, irisin levels doubled after a 10-week stationary-bike training program that involved four or five 20- to 35-minute sessions a week. (Try this Calorie-Blasting Spinning Workout—we’ve even paired it with fast-paced tunes to keep you going.) Another, less obvious, tactic for increasing irisin is to adjust your thermostat. Literally. Lower temperatures may make the white fat you have act like brown fat, shifting your metabolic rate enough to cause weight loss, says Isaacs. One study found that when people spent two hours in a 64°F room and periodically dipped their feet into ice water, their brown fat burned 15 times more calories than it did at room temperature—enough to burn up to nine pounds a year. (Yeah, we're going to skip the ice-water foot bath too.)

Camouflaged Chemicals

Hormones aren't made only by our bodies—they're all around us, lurking in everyday products. Check out three surprising places where weight-gain-inducing hormones have recently been found.

Scented Items
Many cosmetics, shampoos, and household cleaners contain chemicals called phthalates to help scents last. But exposure to high levels of phthalates has been linked to being overweight. Look for phthalate-free on labels.

Canned Food
Some cans are lined with an estrogen-like chemical called bisphenol A (BPA). High-acid foods, such as tomatoes, can cause BPA to leach into the can's contents. Look for BPA-free cans or alternative packaging. (BPA is also found in plastic, so replace your water bottle, stat. Here, The Best BPA-Free Water Bottles.)

Nonstick Cookware

Girls born to women with the highest levels of perfluorooctanoic acid (PFOA) during pregnancy were three times as likely to be overweight than those whose moms had the lowest levels. PFOA is found in nonstick coatings, so use cast iron or stainless steel