When federal health officials reported this week that nearly all contestants on NBC’s “The Biggest Loser” regained the weight they’d lost during the reality TV program’s eighth season — and then some — it may have come as a shock to fans of the show.

But the findings of that federal study were hardly a surprise to obesity experts, who say losing weight is only half the battle for obese and overweight individuals and that maintaining a healthier lower body weight is, in many ways, much harder to do.

Dr. Robert Silverman, a nutrition specialist, tells Newsmax Health federal researchers’ conclusions help to offer new clues to why so many people lose weight only to regain it.

Specifically, the National Institutes of Health scientists found that 13 of the 14 “Biggest Loser” contestants have slower metabolism levels today than they did six years ago, when they lost hundreds of pounds through intensive dieting and exercise during the TV program’s filming. As a result of that slower metabolism — tied the weight loss — they are burning fewer calories than expected when at rest, which has led the pounds to pile back on, the NIH study found.

“It truly explains what most people who have tried to lose weight go through.  Despite spending billions of dollars on weight loss drugs and dietary programs, even the most motivated people are fighting against their own biology,” said Silverman, a chiropractor and certified sports nutritionist from The International Society of Sports Nutrition.

“It shows that the body will fight back for years. There simply is no quick long-term weight loss solution.”

Kevin Hall, a metabolism specialize with the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases, followed the “Biggest Loser” contestants for six years after watching the show’s finale to see if they could keep the weight off.

At the start of the show, Hall and his team found that the obese contestants had normal metabolism levels for their size — meaning they were burning a normal number of calories for people of their weight. But when the show ended — after they lost large amounts of weight — their metabolism had slowed radically and their bodies were not burning enough calories to maintain their thinner sizes.

The study’s findings, published in the journal Obesity, also indicated the contestants’ metabolisms continued to decline that in the years after the show ended, which led them to gain more weight than before. Hall said it appeared that their bodies were intensifying efforts to return the contestants to their original weight.

“After the contestants lost weight not only did the weight come back, the contestants’ metabolism did not recover their basic metabolic rate. Their metabolism continued to slow, hence leading to the weight continuing to pile on.  It showed that their bodies were trying to literally stabilize at their original weight,” Silverman notes.

Metabolism wasn’t the only factor at work, Hall discovered. The contestants battled hunger, cravings, and binges that the researchers linked to lower levels of leptin — a hormone that controls appetite. The contestants started out with normal levels of leptin, but by the show’s finale, it had plummeted — likely producing ravenous hunger cravings.

Even though the contestants' leptin levels increased as they regained their weight after the show ended, they rose to only about half of what they had been when the season began, the researchers found.

The upshot: The key to maintaining a healthy weight may have more to do with metabolism and hormonal balance than diet, extreme exercise, or any other factor. As a result, the long-held advice to simply move more, eat less may not be enough for the one in three Americans who are obese and another third who are overweight, according to the Centers for Disease Control and Prevention.

Susan Rappaport, of NuYu Revolution Fitness Studio, notes that research shows extreme dieting has an 85 percent failure rate — the vast majority of dieters regain any weight they’ve lost when they stop the diet. Yo-yo dieting can also have psychological downsides that may actually make it harder to lose weight.

“Dieting messes with the physical self, mental self, and the bond of trust that one should have with themselves,” she tells Newsmax Health. “[It] is heart breaking, humiliating, creates self-loathing among a longer list of negative feelings about one’s self.”

Silverman and Rappaport say the take-home message for overweight Americans is that short-term dieting and exercise programs — even in the extreme — don’t work in the long run.

Instead, what’s required is adopting healthy habits and lifestyles that can be maintained and sustained throughout your lifetime that keep your metabolism high and don’t lead to unhealthy hormonal changes. Among them:

• Make sure your diet is rich in green vegetables, olive oil, nuts, whole foods, eggs, and lean animal and fish protein — all key staples of the Mediterranean Diet.
• Get enough daily exercise to burn off the calories you consume in your diet. Consider high intensity interval training, which involves short bursts of intense all-out exercise (running, biking, swimming) separated by a few minutes of moderate- or low-intensity activity.
• Aim to sleep seven to nine each night and take steps to manage stress in healthy ways, which studies have shown can help combat weight gain.
• Don’t count calories, count chemicals and additives in food, and look for those with high nutritional values that will leave you feeling full longer.
• Try to make your plate rainbow colored — three-quarters vegetables, oils, and nuts; one-quarter lean protein.
• Consider a liver detox program before and during weight loss to ensure that fat cells will be burned efficiently and will not signal the brain to decrease leptin hormones.

Overall, Silverman cautions against overdoing it, when it comes to diet and exercise programs.

“If you’re killing yourself to lose weight in the gym and dieting, you’re killing your metabolism too,” Silverman says. “As Jim Rohn said, ‘Take care of your body, it’s the only place you have to live.’ ”