Losing weight is hard—and keeping it off can be even harder. In fact, after analyzing 31 long-term studies on the topic, researchers at UCLA found that within five years, up to two-thirds of people on diets regained more weight than they had lost. And you may have heard a lot of buzz about a recent Australian study, because its findings claim to explain one reason why—your hormones can work against you. The depressing implication of the research is that weight loss is nearly impossible to sustain—in particular for those who have been seriously overweight or obese. I was intrigued by this claim but also puzzled because, like me, you’ve surely known people who have lost weight and have kept it off. So how come certain people are able to “overcome” their hormones, while others are not?

For help solving this riddle, I called Michael Aziz, MD. He’s an attending internal medicine physician at Lenox Hill Hospital in New York City and author of The Perfect 10 Diet, in which he discusses 10 hormones that profoundly impact weight loss.


Fifty men and women who were overweight or obese enrolled in the Australian study. They weighed, on average, 210 pounds and were put on an extreme diet for eight weeks, consuming just 500 to 550 calories per day. Dieters who had lost 10% or more of their body weight by week eight were allowed to continue with the study. At the end of week 10, they received individual counseling from a dietician about foods that would help them maintain their weight loss and were encouraged to either start or continue exercising. Throughout the 62-week study, blood samples were taken to monitor assorted hormones.

What the researchers discovered…

In terms of weight, after 62 weeks, study participants had each regained about 12 pounds, on average—about half of the pounds that they had lost by week 10.

From week 10 through week 62, following the initial weight loss, the levels of hormones that influence hunger changed in a way that increased appetite.

Therefore, the researchers argued, regaining weight is—at least partly—due to hormonal changes. They also reported that this information might help pharmaceutical companies design more effective weight-loss drugs to help dieters regulate their hormones and feel less hungry. To me, there were assorted holes in this logic, including the assumption that drugs are the answer.


Dr. Aziz wasn’t surprised by what the study found, but he pointed out many flaws that may have helped lead to the disheartening results…

Participants were on a crash diet. During the weight-loss stage, the people in this Australian study weren’t eating what Dr. Aziz would call “regular” food—they drank diet formulations with chemicals that he said have a negative effect on hormones. Furthermore, he added, consuming so few calories and having such extreme and rapid weight loss likely sent their bodies into a “long-term starvation” mode, in which metabolism slows, calorie burning decreases and hunger rises.

The follow-up was weak. Dr. Aziz added that the researchers did not investigate what participants actually ate in the year after their crash diet and failed to find out what (if any) exercise they did. And both of those factors may have affected the results.

The study wasn’t long enough. People who carry excessive weight generally need at least a year—oftentimes longer—for hormones to even begin to normalize and rebalance after weight loss even if they eat a healthy diet the whole time. These participants were studied for barely over one year, so it’s no wonder that their hormones were out of whack when measured, Dr. Aziz said.


As you might have guessed (but probably don’t want to hear), Dr. Aziz assured me that there is no quick fix for weight loss. The most effective and healthiest way to shed pounds, he said, is by going back to the basics…

1. Eat real, natural foods and get moving. “Losing weight isn’t just about eating low-calorie foods,” said Dr. Aziz. “Many low-calorie foods are processed, so they aren’t filling. You’ll be starving an hour later and will end up ruining your diet.” Besides being low in calories, foods should also contain filling nutrients, such as fiber and protein. So fill your plate with fruits, vegetables, whole grains, nuts and lean meats. Exercise, of course, is also crucial. Aerobic exercises, such as running, brisk walking and bike riding are great because they burn calories, boost your metabolism and have been shown to suppress appetite, he said.

2. Give it time. “Trying to lose a ton of weight in a short amount of time is likely to backfire,” said Dr. Aziz. Instead, be patient, he said—when you let weight loss happen slowly, your hormones will have more time to rebalance and will be less likely to work against you.

While hormones do play a role in weight control, according to Dr. Aziz, what you eat and how much you move around can play an even larger role.