They say it also might explain the fact that while 47 percent of Americans are trying to lose weight at any given time, an estimated 30 to 64 percent of dieters end up gaining back more weight long term then they lost in the short term.

Tomiyama says this study doesn’t mean people should give up on trying to reach a manageable weight. But she says it does mean you should be smart about how you go about it – and perhaps focus on other things like exercising and not overeating.

“I’m saying there are so many ways to get healthier,” Tomiyama says. “Maybe there are better ways out there than just cutting your calories.”

But other experts feel that the study has serious limitations.

W. Scott Butsch, MD, a weight loss expert at Massachusetts General Hospital in Boston, says it’s hard for him to draw conclusions from this research because we don’t know how many calories the participants were taking in before the study. Therefore, he says, it is difficult to know how much, or even if, people were really restricting their food. 

He also points out that those in the study had average body mass indexes of 24 or 25, which is considered the high end of normal body weight. His patients have an average BMI in the range of 43 to 45. 

“Is this really a good sample population for the general public?” he asks. “Probably not. Two-thirds of our population is either overweight or has obesity.”

Dr. Butsch says he also believes weight loss and weight gain are based on a variety of biological and environmental factors and changes, and he says stress probably does play a role in weight control.

“We know there are many complex pathways involved in weight gain and weight loss and stress is one of those responses,” Dr. Butsch says.

And he agrees with Tomiyama, however, that it’s important to be thoughtful about weight loss. He says there are ways to find a weight-loss plan that won’t add stress.

“What we try to do here is we try to individualize diets. It’s not a restrictive diet where you’re off carbs,” Dr. Butsch says. “The thought is to have a balanced diet and something that’s comfortable for you. The same with exercise – let’s try something that’s comfortable for you."