No diet had ever worked for Tom Arnold. By the time the Houston resident reached 638 pounds, he was desperate to lose weight.

Appearing on a reality show finally did the trick.

Arnold lost 162 pounds during his time on “Heavy,” an A&E; series following obese people as they lost weight during a six-month treatment program. Arnold appears in the first episode (9 p.m. Monday).

Knowing his successes and failures were being taped for cable helped motivate him, says Arnold, 37.

“Some moments, you’re like, ‘Oh man, did I just reveal that to the world?’ ” he says. “Exposing my life and my ups and downs and the embarrassing moments to the world, I was nervous about that, but I know there’s a lot of people with similar problems and maybe it could help them in some way.”

The show’s first five episodes were filmed in Austin, and 10 of the 22 participants are from Texas.

The Texas group includes Jodi, a 37-year-old, 367-pound childcare provider in Houston who recently suffered a mini-stroke; Kevin, a 39-year-old, 597-pound teacher and coach in Beaumont who worries he won’t be around to see his children grow up; and Lindy, 37, a 285-pound unemployed woman in Dallas who needs to lose weight so she can get pregnant.

Each of the 11 episodes follows two participants as they spend a month at a weight-loss resort, then try to stick with their healthy habits for five months at home. They meet with trainers, a doctor, a therapist and a dietitian.

“These individuals, they’re addicts,” says David Richardson, a personal trainer in Austin who worked with the Texas participants. “They’re addicted to their drug of choice, which is food. You’re really not just dealing with trying to transform their body in general, you’re really dealing in trying to transform their mind.”

Here’s advice from the show’s stars on how obese people finally can lose the weight:

ASHLEY GREELY

26, bartender and waitress in Austin

Starting weight: 296 pounds

Ending weight: 205 pounds

“Stay strong. You have to have that self-control. It’s going to be tough. You’re going to cry. You’re going to hate what you’re doing. But once you get past that point, it’s like your body resets and you’re like, ‘This is the mode I’m supposed to be in.’ It does get easier.”

TOM ARNOLD

37, unemployed, Houston

Starting weight: 638 pounds

Ending weight: 476 pounds

“Look at it as a marathon and not a sprint. The weight’s going to come off, but it’s not going to all come off in one day, one week, one month. You’re going to have good days, you’re going to have bad days. You have to continue.”

FLOR COX

40, student and state employee in San Antonio

Starting weight: 309 pounds

Ending weight: 243 pounds

“Stop making excuses. I thought I had a (sedentary) job, but it turned out I made it that way. Now I’m never at my desk. I move, I get up and go. If somebody needs something signed, I’ll go up and come back.”

DAVID RICHARDSON

Personal trainer

“Seek professional help. We’re all humans, we all need accountability and motivation. I’m a personal trainer, but even I buy personal training. I do all natural body-building and I know that I can’t do it by myself.”

DR. ROBERT MARVIN

Houston bariatric surgeon who oversaw the Texas participants’ weight loss

“It’s fair to say that people shouldn’t expect to lose weight as quickly (as they did on the show). That’s not a typical environment. It’s a radical change. If they’re significantly overweight they should be being followed by a physician. They may have problems they’re unaware of.”

Website: www.mysanantonio.com/life/health/article/Heavy-Texans-get-help-dropping-weight-in-new-TV-955367.php