GMA: Jim Karas' Fitness Plan

N E W   Y O R K, May 22 -- First Jim Karas told Diane Sawyer she could stand to lose a few pounds. Then he actually helped her lose more than 20!

In about three months, Sawyer shaped up while following Karas' weight and diet plan.

Sawyer has called Karas a "life coach," who helps people change their habits and their outlook on health and fitness.

Now Good Morning America's Antonio Mora is getting in on the fitness act. Mora is known for his sweet tooth around the set of GMA but Karas is going to try to whip him into shape too.

Karas says getting fit is just like flipping a light switch. He says you just have to make a real resolution to change your life. Karas believes that any person, even people over 50, can shed unwanted pounds.

In his new book, Karas debunks many common myths about weight loss and fitness that he believes keeps people from getting themselves healthy and trim.

Karas says the secret to getting in shape lies in strength and resistance training, which doesn't require a lot of equipment.

Cardio for the Heart, Weights for the Waist

The cardiovascular exercise that many people do is not helpful in losing weight, Karas says. It is great for your heart, but doesn't increase your metabolism and so it won't help you shed pounds. The bottom line, Karas says is that muscle burns calories; the more you have, the more you burn.

The evidence is everywhere, he says: Look around your gym and notice the number of overweight people on the treadmills; then compare them with the physiques of people in the weight room. In 1987, there were 4.4 million treadmill users in the United States, and 37.1 million by 1998, Karas notes. Meanwhile, Americans have continued to get fatter.

Karas recommends his clients devote 25 percent of their exercise to cardiovascular work and 75 percent to strength and resistance training. So if you work out for an hour, you should spend 15 minutes on cardio and the rest in the weight room, according to Karas. He recommends working with elastic ropes and free weights that can even be carried with them when they travel.