Hormones may explain why dieters regain lost weight

October 28, 2011 in Nutrition Topics in the News, Weight Management

Hormones may explain why dieters regain lost weight

I'm sure many people found this month's headlines on weight loss and hormones discouraging.  The message: failure to maintain a weight loss is due to hormonal changes, not a lack of willpower.

According to the study, published in the New England Journal of Medicine, such alterations in hormone levels work against you revving up appetite and decreasing calorie-burning for at least a year after losing excess weight.  A perfect recipe for weight regain.

The findings strongly suggest something health professional have long been saying: it's better to prevent weight gain in the first place that to try to battle the bulge once the pounds have piled on.

Earlier research has revealed that during calorie restriction and weight loss, hormonal changes occur that slow metabolism and increase hunger.  But whether these changes persist is not known.  If they do last, it could explain why so many people in weight loss programs regain most of their lost weight- and sometimes more - within 3 to 5 years.

In last week's study, researchers from the University of Melbourne set out to answer that question.  They enrolled 50 overweight or obese but otherwise healthy adults, whose average weight was 209 pounds, in a 10 week weight loss program.

The diet was strict - 500 to 550 calories per day using a very low calorie meal replacement called Optifast supplemented with vegetables. 

During weeks 9 and 10, individuals who had lost at least 10 percent of their weight - the target - were gradually reintroduced to normal foods. (Ultimately, only 34 participants stuck with the study or achieved the required weight loss.)

Weight loss averaged 29 pounds and, as expected, levels of appetite-related hormones changed in such a way to increase hunger and slow metabolism.

After 10 weeks, successful dieters received one-on-one counseling and written advice from a dietitian on a diet that would allow them to maintain their weight loss.  They were also encouraged to get 30 minutes of moderate to intense exercise most days of the week.

During the maintenance phase, participants checked in at the clinic very two months and were contacted by phone between face-to-face visits for ongoing counselling.

Despite the maintenance diet, the subjects gained back roughly half of what they had lost over the next year.

The key finding was that, after one year of maintenance, the levels of six hormones remained altered in a direction that would boost appetite.  The dieters also reported feeling hungrier after the 12 month mark than they did at the start of the study.

The researchers speculate this biological urge to eat - a hormonal response triggered by weight loss - has an evolutionary basis.  Such a response would have benefited a lean person in times when food was scarce. But in modern times when high calorie food is accessible 24/7, these compensatory hormonal mechanisms promote weight regain.

Leslie's Comment: So what to do? Abandon your attempt to lose weight thinking it's futile anyway? In my opinion, that's not the answer.   In my private practice, I have helped many clients lose and successfully maintain their weight loss.  

I am not suggesting hormonal changes that increase appetite don't occur with weight loss. The science says otherwise.

But we don't know whether following a higher calorie weight loss diet that's less restrictive - and one that's much easier to sustain for the long term - causes the same hormonal changes thought to promote weight regain.  It's missing information that this research team hopes to provide through their ongoing research.  

Once you've lost your excess weight, you need to stay focused on your goal: maintaining your loss.  After you've hit your weight goal it's easy for portion sizes to increase, extra snacks to sneak in and the motivation to work out can wane.

Permanent weight loss also requires weighing yourself regularly. The majority of people who have successfully lost weight significant amounts of weight and kept if off for long periods of time weigh themselves at least once per week.   

Regular exercise is important too.   Physical activity burns calories and helps reduce stress, which otherwise might lead to overeating.  Regular exercise also boosts self-esteem, a positive feeling that's linked with making healthy food choices.

Source: New England Journal of Medicine, October 27th 2011.

All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.