TWO FAMILIES COMPETE FOR THEIR FUTURE HEALTH, ON ABC NEWS' "20/20," FRIDAY, JANUARY 7

Two overweight families face the challenge of a lifetime... With the help of Olympic gold medalist Paul Hamm and his twin brother and silver medalist Morgan, two families with real-life problems are facing real-life makeovers. The families have been warned that their health, even their lives, could be in danger if they don't lose weight and get in shape. So they're getting an Olympic-style new diet, new lifestyle and new exercise regime that could change their lives forever. ABC News Correspondent Martin Bashir's report airs on "20/20," FRIDAY, JANUARY 7 (10:00-11:00 p.m., ET) on the ABC Television Network.

Two families from Columbus, Ohio, one of America's top-ten fattest cities (according to Men's Fitness) and one of the fast food capitals of America, volunteered for the unique "20/20" experiment to lose weight by eating sensibly and exercising - with no fad diets.

First the families must weigh in with Ohio State Medical Center Dr. Mimi Ghosh. The Lechner family (father, mother and three sons) weighs in at 1192 pounds. The Rankin family (father, mother and two daughters) weights in at 983 pounds. All are calculated to be clinically obese and at risk for many health problems. Next up is a visit to Olympic coach Miles Avery, who designs personal exercise regimes for both families. Under the guidance of the Hamm brothers, the families do intensive hour-long workouts three times a week. The families then visit dietician Sarah Wick, whose goal is to create an eating program that the Rankins and Lechners can do for the rest of their lives. After two months, will the Olympic lifestyle makeover be a success?

"20/20" is anchored by Elizabeth Vargas and John Stossel. David Sloan is the executive producer.