Exercise to Lose Weight (cont.)

"Strength training itself will not lead to an appreciable amount of weight loss because it just doesn't burn enough calories," says Glenn Gaesser, PhD, FACSM, kinesiology professor and department head at the University of Virginia in Charlottesville.

But what about all that talk that more muscle mass equates to more calories burned, even when you're at rest?

"It's a myth. It's not going to happen," says Gaesser.

The only successful studies to show a significant calorie burn following a weight-lifting workout (afterburn) were done with serious lifters, working out for 60 to 90 minutes at a time and lifting as much as they could on every set.

In fact, Gaesser says, at best, gaining one pound of muscle will help you burn 5 to 10 extra calories a day. You could do that chewing gum.

That's not to say that strength training isn't important for the overall health of the body. But when it comes to burning the most calories, go for cardiovascular exercise. And vary the intensity, says Quist.

"Do aerobic base-building workouts," he says, where you alternate between moderate and higher intensity, either within the same workout or on alternate days.

Quist also recommends cross-training -- that is, doing a range of different activities during your workouts. Not only does this help you keep from getting bored, it's better for your body. Doing different activities recruits different muscle groups. You're also less likely to develop an injury, says Quist, since doing the same thing day after day creates wear patterns on your joints.

Get creative, says Gaesser, whose graduate students teach an entire class on novel ways to burn calories. For example, he says, if you're a golfer, ditch the cart and walk with your clubs. You'll do what you love -- and burn more calories.

Exercise Is Just One Piece of the Puzzle

Keep in mind that exercise is just one portion of a successful weight loss program, say experts.

"Eating and exercise are not separate issues," says Church. "They're intimately connected. Too many people think these large doses of exercise are an excuse to eat whatever you want."

Unfortunately, today food is everywhere. There are candy bars at Home Depot and cheesecakes at Barnes & Noble. Gaesser says his kids can't believe a gas station used to be just a place to get gas. And portions are out of control, says Church - just look at the size of the plates at restaurants.

"It's so much easier not to eat calories than to burn them off," says Quist.

And keep in mind that the definition of successful weight loss is keeping the weight off.

"It's not hard to lose weight," says Church. "Anyone can lose weight. What's hard is keeping it off. Those that combine both diet and exercise keep it off."

But what about metabolism? Many people who have struggled to lose weight believe they have unusually slow metabolisms.

Chances are, "you don't have a slow metabolism," says Church. "It is so rare that of all the metabolisms we've checked (and he does this daily), I can't remember one being legitimately slow."