Jim Bob Duggar and son Josh have lost 57 lbs

Reality TV star Jim Bob Duggar and his oldest son Josh have lost a combined 57 pounds during the past few months by overhauling their diets and working out regularly.

"There are so many benefits to getting in shape and losing 10 percent of your body fat," Jim Bob, 47, told People. "It just makes you feel better. I feel like I'm thinking clearer. It's easier to get up out of a chair."

The father of 19 children has lost 21 pounds to date, slimming down from 220 pounds to 199 lbs by cutting back on soda as well as fried and sugary foods, and working out on the elliptical trainer three to seven miles a day.

The "19 Kids and Counting" star was motivated by his 46-year-old wife, Michelle, who recently lost 40 pounds by working out daily and eating less.

"A few years ago, Michelle had put on some weight and her back was hurting, and the doctor said that if she walked every day and lost some weight she would feel better," says Duggar.

"She lost 40 pounds, did Weight Watchers, and learned how to eat healthy and exercise. Then she started doing the elliptical, and she almost can run off and leave me. I could hardly keep up with her."

Jim Bob's oldest son, Josh, has also lost 36 pounds since October 2012 by cutting back on mindless snacking and exercising regularly. Both Jim Bob and Josh work out with their trainer, former NFL Pittsburg Steelers linebacker Steve Conley.

Josh slimmed down from 238 pounds to 202 lbs by making small but effective behavior changes. "I've learned not to grab that bag of potato chips or all that stuff full of sugar," says Josh, whose wife is expecting their third child.

Jim Bob and Josh are now in the midst of a good-natured weight-loss competition to see who will shed the most weight by April 1. The winner will be served breakfast in bed by the runner-up.

"The competition is working out perfectly," says Josh, 25. "Maybe it will inspire others."