Transcript for Former 'Fat Chef' Fights Food Temptations in the Kitchen
It's hard enough for any of us to lose weigh, but imagine if your whole job is to work in a kitchen. In fact, imagine your whole career was built around making mouth-watering comfort food. Tonight, you're going to meet one of the stars of a show called "Fat chef." A guy who underwent a dramatic transformation. Alex Perez tells us how he did it. If. If you think managing your weight is tough, imagine what it's like for a chef. Piles of bacon everywhere. You know? Tempting. Reporter: He's a star chef? Cleveland, Ohio. He owns six restaurants and a food truck specializing in comfort food. We sell more short orderner this restaurant than any other in Ohio. 1,300 to 1,500 calories would be a good estimate. A day's worth of calories in this one meal. Yeah. Reporter: But for Rocco, it was his profession that almost killed him. I was probably 8,000 to 10,000 calories a day. I thought I would end new a pine box because there wasn't a casket to fit me. This was him at his he have viest. 497 pounds. Now he's down to 240 pounds. Millions of Americans struggle with obesity. There are over 100 million dieters in the U.S., making up to five dieting attempts each year. Rocco's turning point came after seeing pictures of a trip to Italy. The.ic chur, man. I was frankly unhealthy, unhappy, unsavory to look at. Size 54 pants. A fit adult is about half that, 28, 30. Rock bottom was that. I would have to ask for extenders on the plane at 400 pounds. I didn't have an offswitch. I would just eat, eat, eat. But two years ago, Rocco took his battle public. The food network cast him out of 3,000 contestants for the TV show "Fat chef." My name is rockie Whalen. I'm the biggest, baddest chef in Cleveland, Ohio. Reporter: The pressure was on to lose weight as America watched. You've got to change yourself. What was the most difficult part about being into the show. Walking into the gym for a first time. It was a humbling moment to take my shirt off and get on a scale. Reexercised two hours a day for six days a week. I'm a little bit nervous. Drum roll, please. At the end, he lost a staggering 85 pounds. 256.2! But the real challenge came after the cameras were off. When you don't have a motivating goal like stepping on a scale for all your friends. They're all cheering, it's more difficult to maintain. We're going to the gym and it's 6:20 in the morning. It's cold, it's dark. This is where you find out who you are and what you're made of. Rockie transformed his entire way of life, losing a staggering 140 pounds. Planning his entire day around workouts and small meals. I run, I do tread meal. Fitness revolution is three to four days a week. I'm humble in this arena. I'm still not happy, though. I mean, I have a goal in mind. Which is? 240 pounds. Nice work. Michael was another contest assistant on "Fat chef." I was so disgusted at how far I let myself go. He, too, faced a similar struggle after the show ended. 430.0. Just about 80 pounds. When I started "Fat chef" I was just as 500 pounds. In that four months, I lost 100 pounds. He lost an additional 60 pounds after the show, but when his bakery business went under, the stress took over. Michael gained back 20 pounds in the last year. The hardest thing for my diet when I had to close my business was the stress. The stress was overwhelming. And, you know, and whenever I have that, that's when you really make bad choices. I'm an emotional eater. But I recognized it and I stopped it quick. And I erased it. Now he works as an executive pastry chef in New York City. And Michael says he back on track. So right now, I'm 360. I want to get down to 260. I need to lose 100 pounds to be where I want to be when I was in high school. Reporter: Even for Rocco, working out is just half the battle. Each day going into work means fighting the temptation to taste, a war fought with backup from his employees. You don't equip yourself with a spoon. And we have a no policy taste. All my guys with the tasting spoons are plastic spoons, tasting spoons. So I just don't equip myself with a spoon. I'll say Brian taste this, T.J. Taste this. What's this taste like. Does it have enough salt or butter? Finish it with more butter. Once you've been that big, you can always return to being that big. No doug, brother. Do you think about that? Every day. But Rocco has trained himself to resist. The one dish you sold the most of here, but you won't it pip. I won't. I know what it takes like. I have eaten it over the years. It's delicious. You're going to verify that. It looks so good you almost know it's bad for you. While I dug into the suck lent beef, Rocco opted for the healthier version. Grilled chicken breast and quinoa. Oh, wow. It's good you didn't have this back to back with this. This is very good. But it's hard to follow it up right after you've had a bite of the kobe beef. It's hard to resist. I'm Alex Perez for "Nightline" in Cleveland, Ohio.
This transcript has been automatically generated and may not be 100% accurate.