Congratulations, you're losing weight. But keeping off is where the battle of the bulge begins. Here is chris connolly. Reporter: Congratulations! One of those quick, just stop eating that diets has...
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Congratulations, you're losing weight. But keeping off is where the battle of the bulge begins. Here is chris connolly. Reporter: Congratulations! One of those quick, just stop eating that diets has helped you lose tons of weight. Well, guess what? Experts estimate a belt-busting 95% of dieters will eventually regain those lost pounds. Let's go, let's go,. Reporter: So if staying trim for keeps is your goal, pete thomas is your guy. Pete doesn't just help others, he's maintained his own weight loss for eight years now. The author of lose it fast, lose it forever is a sleek 238 today, he used to be more than 400 pounds when he first tipped the scales on the biggest loser. Dropping 185 pounds made him a winner. Still, he remembers the agony of failure -- while on the show -- when he found chocolates in a laundry room. These things had me. The only way that we could get those out of our -- out of the house, was to put them in a garbage can, and to pour liquid tide on them. Reporter: Just because ng them in the garbage can wasn't bad enough. That's the thing! That's the thing! You would've been willing to go into the garbage can to eat them. I did. Reporter: And this is on a weight loss show. On a weight loss show. Proven phenomenon, trigger foods do exist. Reporter: Chris powell is the trainer on "extreme makeover: Weight loss edition." The folks I work with, there are certain foods that if they have them, it's like crack cocaine for them. Reporter: Can you not have a bag of cookies even in your home? It's best to keep that kind of food outside of the house. A can of pringles in my house won't last 20 minutes. Another thing. Reporter: You, the ultimate success story. Yes. Absolutely. You can't have a can of pringles in your home. No I can't. Well, I can, but then I would be gaining it back, and I wouldn't be here talking to you. Reporter: Even with workouts like these, what makes maintaining weight-loss so hard? Science says even 12 months after slimming down, parts of your body want you to get fat again. According to dr. David katz, director of the yale university prevention research center. Fat cells do not like being starved, and they make a fuss about it. And so the way they complain about g starved is they stop sending your brain the signal that we've had enough food, we wind up being hungry. This is a great filler. Reporter: For pete, tricking those fat cells into thinking they are getting enough food requires an approach he calls "fluid, filler, feast." I have a diet pop. That is my fluid. My filler would be the soup and the green beans. Reporter: Why do you call that filler? Because it's literally filling up my stomach. And then the feast is going to be what I actually want. The key is we want lower calorie filler. If you eat a lot of wholesome foods, they have fewer calories, but larger volume. They tend to fill us up. Reporter: He maps out plenty of good food with the bad stuff out. I could have nine slices of bacon and now I eat nine slices of turkey bacon. Four eggs of eeg beaters and crystal light. The calories from 1,000 calories to 300. Reporter: One tip for healthy eating that you haven't pointed out is have a near naked picture of yourself at 400 pounds within view of the kitchen. Does that help? At all times! At all times! Reporter: What happens when you have a bad night? Yeah. Had a few of those, and what it each is, a bad night, and a bad day, does not equal a bad week. And so, you simply have to catch yourself, and get back on track. Come on, slow and easy. Reporter: It's not all the time when you can see not one, but two miss south carolinas working out side by side. Helping to train 1994 winner kristie greene lee, who's already lost 14 pounds since getting started, is 2011 miss south carolina bree boyce. Like millions of americans, and such celebrities as kirstie alley, janet jackson, and carnie wilson, bree spent years as a yo-yo dieter. The soup diet, the carb diet, everything. I have tried every single di that you could think of. Reporter: How much weight did you lose when you went on the atkins diet? I lost 60 pounds. And what happened after that? I gained 70. Reporter: She weighed 234 pounds in high school, where she'd get teased and feel ashamed. Her date canceled on her the night before the prom. Oh, it -- you feel like such a failure. I was in a really dark place at a young age. And it was just really tough for me, being so young, and missing out on those things in life. Reporter: Four years ago, bree lost more than 100 pounds, and has kept if off by getting educated about exercise and nutrition. Scrambled egg whites. Oatmeal, half a grapefruit. Reporter: And not just dieting. You're setting yourself up for failure if you say "oh, well, I'm on a diet," because then you're restricting yourself. You're going to end up binging, and gaining weight back. Reporter: Instead, bree regained her self-esteem. After winning the miss south carolina pageant, she was one of 12 semi-finalists at last year's miss america, but bree says now that she overdid it. That the super-skinny form she sported in the fitness competition didn't suit her. It's not all about just being skinny, because I've been there, and I've done that, and I wasn't healthy. The thing that matters the most is that you believe in yourself, you love yourself, and that you're taking care of your body. Reporter: Now at 134 pounds, bree keeps her old size-18 jeans around as future motivation -- to maintain her new healthy self. Push, push. Instead of saying you need to lose weight, what you should be saying, I will achieve a healthy weight and maintain
