Working Submarine Controls

New Study in NEJM: Controlling versus Losing Weight

Weight loss is a minor part of obesity care. It’s blindingly obvious, but most people have a tough time wrapping their heads around this basic fact. A new study in the New England Journal of Medicine today tells this story in a very elegant way. It’s all about controlling weight over time.

Getting Weight Loss Out of the Way

The whole point of this study is not weight loss. This was an experiment that was all about maintaining a reduced weight. Subjects entered the study with a BMI between 32 and 43. Before the experiment began, 195 subjects lost weight on an eight-week very-low-calorie diet (VLCD). On average, they lost 12 percent of their initial body weight.

Of course, anyone who is living with obesity can tell you that weight loss is easy. The real challenge comes after that – controlling weight over time. And that’s what this study was all about. After initial weight loss on that VLCD, researchers randomly assigned subjects to four different groups. One group went back to their normal patterns of living, plus a daily placebo injection. That’s the control group.

The exercise group received the daily placebo plus a flexible exercise program of moderate or vigorous intensity. Then a liraglutide group received the approved daily dosage for obesity, but no prescription for exercise. Finally, one group received both liraglutide and the exercise program.

The findings are straightforward. At the end of the year, the control group regained almost half of the weight they had lost. The single-intervention groups were both better than placebo. But the outcomes for liraglutide plus exercise delivered the best results. Subjects lost a bit of additional weight, improved their metabolic health, and achieved better cardiorespiratory fitness.

Chronic Care for a Chronic Disease

An excessive focus on weight loss surrounds us. Folks who want to deny that obesity is a problem call it all diet culture and they have a bit of a point. But real obesity care is about health first and maintaining a healthy weight over time. Losing weight is a very small part of that proposition – even though it can be important. Controlling weight over time is the greater challenge.

It’s important to understand that after someone has lost weight, their physiology changes. An entire special issue of the Obesity research journal explains what’s known and the knowledge gaps in this important subject.

With an elegant and well-controlled study in the NEJM, researchers Julie Lundgren and colleagues are pointing the way to better obesity care with both pharmacotherapy and physical activity.

Click here for the Lundgren study and here for the special issue of Obesity on physiology of the weight-reduced state. For reporting on the Lundgren study (which unfortunately focuses on weight loss) click here.

Working Submarine Controls, painting by Eric Ravilious / WikiArt

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May 6, 2021