"HALF THEIR SIZE" - LOSING WEIGHT AND KEEPING IT OFF IN THE NEW YEAR

"20/20" and PEOPLE Magazine Collaborate on a Special Hour, Friday, January 4 on ABC

It's the New Year, a time when many Americans make resolutions to get in shape. From successful ways to lose weight to keeping the weight off permanently, "20/20" and PEOPLE magazine team up for a must-see hour to kick-start any weight-loss program. It's time to lose the weight with an all new special "20/20" -- "Half Their Size" -- airing on FRIDAY, JANUARY 4 (10:00-11:00 p.m., ET) on ABC. Anchored by Elizabeth Vargas, reports include:

Real People: For the past 11 years PEOPLE magazine has published a special issue, "Half Their Size," featuring readers who've lost half of their body weight through diet and exercise. "20/20" profiles three of this year's featured stories and details each one's emotional journey. Deborah Roberts reports.

Keeping It Off: For some people losing weight is easy� keeping it off is the hard part. Why do the majority of dieters fail to keep the weight off permanently? "20/20" learns the secrets of long-term weight loss from people like Pete Thomas, who once weighed in at over 400 lbs. He has kept 185 lbs off for eight years and counting. We also check in on Miss South Carolina Bree Boyce, who was featured on the cover of PEOPLE's "Half Their Size" issue last year. Chris Connelly reports.

Sidekicks: Hollywood is the land of glamorous, beautiful and thin celebrities. But what's life like when you work for the rich and thin but aren't as svelte? "20/20" profiles several sidekicks, including: comedienne Kathy Griffin's assistant, Tiffany Rinehart, who lost more than 80 pounds after seeing herself on Griffin's reality show, "My Life on the D List"; Bethenny Frankel's foodie buddy, Nick; and John Taylor, a 350-pound guitarist who toured the world with the Jonas Brothers. Nick Watt reports.

Weight Loss Scam: Jim Avila reports on a weight loss marketing scam that authorities say took in million in sales while doing little to help people slim down.

Ruby: For four seasons Ruby Gettinger was the star of the hit docudrama "Ruby" on the Style Network. The show followed her every move as she struggled to go from more than 700 lbs to 250 lbs. But she never reached her goal weight, and even gained the weight back. Her show was canceled, leaving fans on the edge of their seats. Ruby reveals why and how she sabotaged her weight loss, and what she's doing now to turn her life around. Amy Robach reports.

David Sloan is executive producer of "20/20."