My wife could be a circus performer. Her trick: crunches. We once had a contest to see who could do the most without stopping, and she was still crunching away long after I’d moved on to Monday Night Football.
It was amazing to watch. And great fun. But here’s what it wasn’t: an effective workout.
In fact, a recent study in the Journal of Strength & Conditioning Research found that crunches, situps, and other abs-only exercises don’t do much of anything to reduce belly fat. It’d take 250,000 crunches to burn just one pound of fat. If you did one per second, that would take you three days!
“Crunches and such are great to increase abdominal muscle,” says study researcher John Smith, Ph.D., HFS, an assistant professor at Texas A&M University–San Antonio, “but just performing these alone will not increase caloric expenditure above that which is needed to facilitate sizeable fat loss.”
The runners among you might be thinking: I knew that! But you should also know that aerobic exercises like running aren’t particularly great for weight loss either, which explains why you’re not sporting six-pack abs yet. A study published in Obesity found that after a year of hourlong aerobic sessions six days per week, people lost only 3.5 pounds. (As with the crunch study, researchers asked participants to leave their diets unchanged.) That’s basically one pound of weight loss for every 100 hours on the treadmill. Bank stocks have a better return on investment.
So if you want a flat midsection, what should you do? First, watch your diet. Start by breaking the 20 Habits That Make You Fat. Next, combine strength training andcardio in your workout routine. That doesn’t mean lifting one day, jogging the next. There are plenty of ways to combine strength and cardio into one workout, such as circuit training. In a recent study of obese adolescents, those who did 30 minutes of cardio and 30 minutes of strength training three times per week for a year lost nearly four times more fat than those who did all cardio.
There’s another major benefit to the strength-cardio combo: “Proper diet and cardio will make you weigh less, but that weight loss isn’t fat alone—you’re losing muscle, too, and not building anything to give your body athletic shape,” says Jeff Halevy, CEO of Halevy Fitness in New York. “But if you’re after fat loss, aside from accelerating it, strength training will also preserve muscle. This means when the fat is gone, you’ll have a lean, athletic body to show for it.”
Strength training has a big effect on post-workout calorie burn, which may help explain why it’s so essential to fat loss. A second study in the Journal of Strength & Conditioning Research found that, after a strength-training session, your body burns 8 percent more calories than normal for the next 72 hours.