Timing is everything when it comes to weight loss, research shows

October 24, 2012, University of Michigan Health System

Joint research between the University of Michigan and the Argentina-based National Council of Science and Technology (CONICET) has shed light on one of the most frustrating mysteries of weight loss – why the weight inevitably comes back.

A novel animal model showed that the longer mice remained overweight, the more "irreversible" obesity became, according to the new study that appeared online ahead of print Oct.24 in the .

Over time, the static, obese state of the mice reset the "normal," body weight set point to become permanently elevated, despite dieting that initially worked to shed pounds, authors say.

"Our model demonstrates that obesity is in part a self-perpetuating disorder and the results further emphasize the importance of early intervention in childhood to try to prevent the condition whose effects can last a lifetime," says senior author Malcolm J. Low, M.D., Ph.D., professor of molecular and integrative physiology and internal medicine.

"Our new animal model will be useful in pinpointing the reasons why most adults find it exceedingly difficult to maintain meaningful from dieting and exercise alone."

The lead author of the study was Viviana F. Bumaschny, M.D., assistant investigator of CONICET.

Obesity affects more than 500 million adults and 43 million children younger than age 5, while related illnesses are the leading preventable cause of death. Individuals who are overweight have a much higher risk of , hypertension, and cardiovascular diseases.

One of the major strengths of the research was a new model of obesity-programmed mice that allowed weight loss success to be tracked at different stages and ages by flipping a that controls hunger.

Turning on the switch right after weaning prevented the mice from and ever becoming obese. Similarly, mice that remained at a healthy weight into young adulthood by strict dieting alone were able to maintain normal weight without dieting after turning on the switch. However, chronically overfed mice with the earliest onset of obesity never completely returned to normal weight after flipping the switch, despite marked reduction in food intake and increased activity.

The new findings may raise questions about the long-term success rate of severe calorie restriction and strenuous exercise used later in life to lose weight, such as the extreme regimens seen in the popular reality television show "Biggest Loser."

"Somewhere along the way, if obesity is allowed to continue, the body appears to flip a switch that re-programs to a heavier set weight," Low says. "The exact mechanisms that cause this shift are still unknown and require much further study that will help us better understand why the regaining of weight seems almost unavoidable."

Explore further: Yo-yo dieting vs. obesity? Dieters may be healthier, live longer, study finds

More information: J Clin Invest. 2012;122(11):4203-4212. doi:10.1172/JCI62543.

Related Stories

Yo-yo dieting vs. obesity? Dieters may be healthier, live longer, study finds

June 6, 2011
Yo-yo dieters may be healthier and live longer than those who stay obese, a new Ohio University study finds.

Stepped-care intervention results in weight loss, at lower cost

June 26, 2012
Although a standard behavioral weight loss intervention among overweight and obese adults resulted in greater average weight loss over 18 months, a stepped care intervention resulted in clinically meaningful weight loss that ...

Study finds that yo-yo dieting does not thwart weight loss efforts or alter metabolism long term

August 14, 2012
Yo-yo dieting – the repetitive loss and regain of body weight, also called weight cycling – is prevalent in the Western world, affecting an estimated 10 percent to 40 percent of the population. The degree to which ...

Recommended for you

Race plays role in regaining weight after gastric bypass surgery

November 15, 2018
African Americans and Hispanic Americans who have undergone Roux-en-Y gastric bypass (RYGB) are at greater risk to regain weight as compared to Caucasians. To date, no study has addressed the effect of race on weight regain ...

Simple tips can lead to better food choices

November 13, 2018
A few easily learned tips on eating and food choice can increase amount of healthy food choices between 5 percent and 11 percent, a new Yale University study has found.

Study finds that in treating obesity, one size does not fit all

November 13, 2018
Analyzing data from more than 2,400 obese patients who underwent bariatric weight-loss surgery, researchers identified at least four different patient subgroups that diverge significantly in eating behaviors and rate of diabetes, ...

Exercise makes even the 'still overweight' healthier: study

November 13, 2018
(HealthDay)—Heavyset folks who exercise regularly shouldn't get discouraged if they can't seem to shed more weight, no matter how hard they try.

Scientists shine new light on link between obesity and cancer

November 12, 2018
Scientists have made a major discovery that shines a new, explanatory light on the link between obesity and cancer. Their research confirms why the body's immune surveillance systems—led by cancer-fighting Natural Killer ...

Genetic factors tied to obesity may protect against diabetes

November 2, 2018
Some genetic variations linked with obesity actually protect against Type 2 diabetes, heart attack and stroke, new findings suggest.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.