It's the promise of late-night TV infomercials, SkyMall gadgets, and the star of our fitness fantasies: spot-reducing fat in those "trouble zones." After all, everybody has one or two.
But is it a dream worth chasing?
Scientists sure have tried (see our analysis of the Polinquen Program). The closest they've come was in one University of Copenhagen study during which men performed single-leg extensions with light resistance for 30 minutes straight. Researchers found that both blood flow to and breakdown of the fat cells in the exercising leg increased compared to the resting leg. Problem was, the difference was so minute that it had little to no real-world significance. In fact, in another study published in Medicine and Science in Sport and Exercise, after 104 participants worked their non-dominant arm for 12 weeks, MRI scans showed that the exercised arm didn't lose any more fat than the unworked one.
Why? The fat in fat cells exists as chemical compounds called triglycerides. Muscles, however, cannot directly use them as energy; it would be like trying to fuel a Jaguar with crude oil. Instead, the fat must first be broken down into glycerol and free fatty acids, which then enter the bloodstream to provide muscles the energy they need, according to Bret Contreras, C.S.C.S., author of Bodyweight Strength Training Anatomy. That means the fat can come from any part of your body, not just the one you're flexing.
However, based on the fat tissue's location, it can be separated into two types: subcutaneous and visceral. The latter is responsible for men's most troublesome spots—the stomach and chest—and (get ready for your silver lining) it's the easiest type to trim from your frame, according to Harvard Medical School.
Men naturally carry more fat receptors in the midsection compared to women. So when junk-food snacks trigger the release of insulin, and poor sleep or work deadlines send the stress hormone cortisol into overdrive, hormones up the body's estrogen levels (yes, the "girl hormone"), which signals the body to store fat that, in turn, goes straight to the stomach and chest, according to exercise physiologist Marta Montenegro, C.S.C.S. Situated in the abdomen around vital organs, visceral fat is linked with increased risk of diabetes, heart disease, and other chronic conditions, earning its reputation as the most dangerous type of fat.
However, since visceral fat is so reactive to hormones—and don't forget the ones that help regulate muscle growth, metabolism, and appetite—it's the first to get zapped when men adopt healthy lifestyles and weight-loss habits, Montenegro says.
So what's the right way to blast your fat (the abdominal variety included)? Montenegro suggests working your body's largest muscle groups with multi-joint strength exercises, such as squats, push-ups, shoulder presses, and deadlifts. Besides burning more calories than crunches (one pound of fat equals 3,500 calories, after all), working larger muscle groups is linked with the greatest muscle formation and resulting metabolic afterburn possible. What's more, high-volume, low-rest exercise protocols (such as performing 3-4 sets of 10-12 reps with no more than 60 seconds rest in between) stimulate the greatest release of growth hormone and testosterone—both of which are necessary for building calorie-torching, physique-making muscle.
The bottom line: Spot-reduction exercises are far from the lipo-alternative they claim to be. But if, like most men, your trouble area is situated around your abdomen, your body is built to troubleshoot your trouble zones. All you have to do is help it along.