By the time you’re obese or morbidly obese, your chance to get back to your normal, healthy weight is very unlikely, according to a new study out of King’s College London.

The study, published in the American Journal of Public Health, found that one in 210 obese men and one in 124 obese women would recover their normal weight. For severely obese people, that number is even smaller: one in 1,290 for men, and one in 677 for women. What this means is that we aren’t fighting obesity as effectively as we should — and simply suggesting dieting and exercise may not be the trick to getting people back to normal.

“Once an adult becomes obese, it is very unlikely that they will return to a healthy body weight,” Dr. Alison Fildes, an author of the study, said in the press release .

The researchers examined data on 278,982 participants, reviewing their health records from 2004 to 2014. They tracked the probability of obese people recovering normal weight or at least a 5 percent reduction in body weight. A good chunk of people were able to see a 5 percent reduction in body weight annually (one in 12 men and one in 10 women), but most of them (78 percent) had regained their weight within five years. Of course, the number of people who got back to their normal, healthy weight completely was extremely low — and the researchers observed plenty of weight cycling, or the yo-yo effect in which they lost weight, gained it back, lost it again, and gained it again.

What does this mean? The researchers note that unfortunately, these results show that current weight loss plans for large populations don’t appear to be working.

“Losing 5 to 10 percent of your body weight has been shown to have meaningful health benefits and is often recommended as a weight loss target,” Fildes said in the press release. “These findings highlight how difficult it is for people with obesity to achieve and maintain even small amounts of weight loss… [T]he current system [of weight loss] is not working for the vast majority of obese patients.”

In many cases, diet and exercise is the common sense solution to weight loss — but for many obese patients, the only options are medications or gastric bypass surgery. But perhaps prevention is key here — if we focus on how to prevent weight gain and obesity in the first place, it won’t be as hard to work that weight off.