The 7 Laws of Leanness

Why do some people seem naturally thin—able to torch cheeseburgers instantly and never gain a pound? And why do some of us—okay, most of us—sweat and diet and sweat and diet some more, and never lose enough to get the body we want?

Because those “naturally thin” people actually live by a series of laws that keep them from ever gaining weight. And if you know their secrets, you can indulge and enjoy and never gain another pound as long as you live.

As the editor-in-chief of Men’s Health, I’ve spent the past two decades interviewing leading experts, poring over groundbreaking studies, and grilling top athletes, trainers, and celebrities for their health and fitness advice. And I’ve learned that what separates the fit from the fat, the slim from the sloppy, the toned from the torpid, is a set of rules. And what’s amazing is that none of them involves spending hours on a treadmill, eating nothing but grapefruit and tree bark, or having part of the small intestine replaced with fiberfill. Follow these simple rules and weight loss will be automatic.

LAW #1: Lean People Don’t Diet

What? Of course lean people diet! They’re just magically better at denying themselves than the rest of us are, right?

No. In reality, studies show that the number one predictor of future weight gain is being on a diet right now. Part of the reason is that restricting calories reduces strength, bone density, and muscle mass—and muscle is your body’s number-one calorie burner. So by dieting, you’re actually setting yourself up to gain more weight than ever. And a recent study in the journal Psychosomatic Medicine showed that tracking your diet in a food journal can actually boost your stress levels, which in turn increases your level of a hormone called cortisol, and cortisol is linked to—you guessed it—weight gain.

FAT-FIGHTING FIBER: Get 25 grams of fiber a day—the amount in about 3 servings of fruits and vegetables—and you can boost fat burn up to 30 percent. For more tips on fighting fat and toning your midsection, follow me right here on Twitter. Or try any of these 50 Ways to Lose 10 Pounds!

LAW #2: Lean People Don’t Go Fat-Free

A European study tracked nearly 90,000 people for several years and discovered that participants who tried to eat “low fat” had the same risk of being overweight as those who ate whatever they wanted.

Fat doesn’t make you fat, period. Indeed, you need fat in your diet to help you process certain nutrients, like vitamins A, D, and E, for example. And many “fat-free” foods are loaded with sugar, and therefore have even more calories than their full-fat cousins. Even the American Heart Association says that fat-free labels lead to higher consumption of unhealthy sweets. Fat keeps you full and satisfied. Fat-free will send you running back to the fridge in an hour, hungry for more.

LAW #3: Lean People Sit Down to Eat

In fact, the more you sit down and enjoy your food, the leaner you’re going to be. Punishing yourself only makes you fat!

Greek researchers recently reported that eating more slowly and savoring your meal can boost levels of two hormones that make you feel fuller. And researchers at Cornell University found that when people sat down at the table with already full plates of food, they consumed up to 35 percent less than they did when eating family-style—that is, by passing serving dishes around the table.

FIX IT WITH FOOD! Check out our list of the 40 Foods with Superpowers—foods that, even in moderation, can strengthen your heart, fortify your bones, and boost your metabolism so you can lose weight more quickly.

LAW #4: Lean People Know What They’re Going to Eat Next

Planning your responses to hunger may help you shed pounds faster, say Dutch researchers. They posed their subjects questions like “If you’re hungry at 4 p.m., then . . . what?” Those who had an answer (“I’ll snack on some almonds”) were more successful at losing weight than those who didn’t have an answer.

One of the best things about the brand-new Eat This, Not That! 2012 is that it helps you find fat-fighting food no matter where you are: movie theater, coffee shop, vending machine. It also includes this list of foods that should never see the inside of your belly: The NEW 20 Worst Foods in America.

LAW #5: Lean People Eat Protein

In a recent European study, people who ate moderately high levels of protein were twice as likely to lose weight and keep it off as those who didn’t eat much protein.

A New England Journal of Medicine study looked at a variety of eating plans and discovered that eating a diet high in protein and low in refined starches (like white bread) was the most effective for weight loss. Protein works on two levels: First, you burn more calories to digest it. Second, because your body has to work harder to digest a Big Mac than, say, a Ho Ho, you stay fuller longer.

STEALTH HEALTH FOODS: Power up your diet by expanding your menu. Here areThe 7 Healthiest Foods You're Not Eating.

LAW #6: Lean People Move Around

I don’t mean climbing Kilimanjaro, breaking the tape at the Boston Marathon, or spending 24 hours at 24 Hour Fitness. I mean going for a short bike ride (20 minutes burns 200 calories), taking a leisurely walk (145 calories every 51 minutes), wrestling with your kids (another 100 calories smoked in 22 minutes), or fishing (there’s 150 calories gone in an hour—even more if you actually catch something).

Simply put, fit people stay fit by having fun. Scientists have a name for how you burn calories just enjoying yourself. It’s called NEAT: non-exercise activity thermogenesis. Sounds complicated, like something only policy wonks at a global warming summit are qualified to discuss. But it’s pretty simple: Pick a few activities that you enjoy, from tossing a stick for your dog to bowling with your best friend, and just do them more often. The average person makes 200 decisions every day that affect his or her weight. If you choose the fun option more often than not, you’ll see results.

LAW #7: Lean People Watch Less TV

Instead of calling it the boob tube, maybe we should call it the man-boob tube. About 18 percent of people who watch less than two hours of TV a day have a body mass index (BMI) of 30 or more—the cutoff line forobesity, according to the Centers for Disease Control and Prevention. But of those who watch more than four hours of TV a day, nearly 30 percent have a BMI that high, according to a study in the Journal of the American College of Cardiology. 

Look, I like TV. But all things in moderation: In a study at the University of Vermont, overweight participants who cut their daily TV time in half (from an average of 5 hours to 2.5 hours) burned an extra 119 calories a day. And a recent study of people who successfully lost weight found that 63 percent of them watched less than 10 hours of TV a week. Want more? A study in the journal Annals of Behavioral Medicine reported that lean people have an average of 2.6 television sets in their homes. Overweight people have an average of 3.4. Finally, researchers in Australia recently discovered that every hour in front of the television trims 22 minutes from your life. Yikes!

Breaking any of these seven laws occasionally is fine. Just don't make a habit of it. Likewise, make sure you haven't fallen into any of these 20 Habits That Make You Fat.