The Scientific Reason Why You're Yo-Yo Dieting in the First Place
If you recognize yourself as being caught in this process, know that it's okay and there's no shame. Diets that preach restrictions often lead to "overcompensation" or binge eating. "Over time, this goes into a chronic cycle," says registered dietitian Ginger Hultin, a spokesperson for the Academy of Nutrition and Dietetics and the owner of Champagne Nutrition in Seattle.

The need to eat and feed yourself adequately is a matter of biology. Experts like to sum it up this way: You didn't fail the diet — the diet failed you. "What you're dealing with is actually biology. It's so strong, and no amount of willpower or diet plan will let you overcome what the body is programmed to do. As soon as you restrict too much, limiting a macronutrient (carbs, fat, protein) or calories, the body rebels by slowing the metabolism," Hultin says. In short: You don't lose weight as quickly and you are likely to gain weight over the long term. Also, once you lose weight, your metabolism slows naturally. A smaller body requires fewer calories.

In the popular Biggest Loser diet study, researchers explained why weight can quickly rebound. When looking at 14 past participants of the extreme weight loss show, they found that their resting metabolic rate (RMR) decreased by 704 calories per day, on average. Essentially, that means their metabolism slowed down.

You would expect metabolism to slow following weight loss because their bodies were smaller. But even after weight regain, their RMR continued to be lower than what would be expected for their now-larger size. The participants lost about 128 pounds, on average, by the end of the show, but they regained about 90 pounds after six years.

Another reason for the gain? It's important to remember the behind-the-scenes details of the competition: The participants worked out for several hours a day with a trainer and had food provided for them. Once they were on their own again, they no longer had access to those things, so it was likely more difficult for them to maintain their weight in a real-life setting.

Here's what researchers found was key to maintaining weight loss: exercise. In a later study involving contestants from The Biggest Loser, the median weight loss was 13 percent of initial body weight after six years. But those who kept the most weight off — 25 percent of their body weight — had one defining factor: They increased their time spent exercising by a whopping 160 percent from what it was before the show. Some participants regained slightly more weight (up to 5 percent) than their starting weight — and they only increased their physical activity by 34 percent. That sounds like a tall order, and for many people, it probably is. The study authors estimate that the amount of activity needed to maintain weight loss is 80 minutes of moderate activity or 35 minutes of vigorous activity daily.

How to Get Back on Track With Your Weight Loss Plan
This back-and-forth cycle can set you up to feel like a failure if you're set on losing weight. "It's so frustrating," says Hultin. "Many of my clients have a lifelong history of weight cycling, a pattern that started as children and continued into their teen and adult years," she says.

But you can get off the roller coaster. It's possible to break free of the fads, put in the mental work, and come out healthier and happier than before. No more thinking that you're a failure because you couldn't stick to a crazy fad diet.

Here's how to begin.

Cut the restrictions. Watch out for any diet that restricts an entire food group or forces you to cut out everything that you love, says Hultin. "It's these unrealistic plans that cause this weight cycle," she says.

Make a mental shift. "A large part of yo-yoing is not changing the fundamental psychology behind eating," says Tiffany Wright, PhD, aka the Skinny Coach, a weight loss expert in Los Angeles who has studied the psychological and behavioral factors that lead to overeating. Because our daily environment tends to be littered with these triggers (like the neon sign of a fast-food restaurant on your way home after a stressful day of work), losing weight is not about how much willpower you have or how well you can follow diet rules. "While most people can go on any diet for a certain amount of time, it doesn't address the triggers or associations that lead you down a path of weight gain in the first place," says Dr. Wright. That's why it's so easy to go back to your former habits.

Find help. Whether your goal is to lose weight or adopt healthier habits that will improve your health (with or without weight loss as the end goal), tap into the wisdom of someone who knows this stuff and can guide you along the way. "There's this sense that you can do it on your own, but I think that people need help from a professional," Wright says. "I think of this as a skill that needs to be learned, like gymnastics or cooking. It's okay to get help."

Consider your headspace. You have to address your relationship with food, particularly if you've developed fears involving it. "Is there a potential for disordered eating? I think many people walk around in that space without support," says Hultin. Disordered eating is a broader term that doesn't fit into typical definitions of anorexia or bulimia, but it still deserves to be taken seriously, as it can lead to health problems, according to the Academy of Nutrition and Dietetics. Talk to your doctor or a dietitian who can offer a referral to a therapist who specializes in eating disorders, if needed.

Look beyond the scale. Weight isn't everything. Are your labs normal? Are you sleeping okay? Exercising appropriately? While it may seem easier to mark your progress with the scale, there are other, often overlooked changes that also impact your overall health, says Hultin.