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By Matthew Rees

Food and Health Fact #166: Progress -- but not a panacea -- in addressing severe obesity

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The nexus between diet and health – cancer in particular – is crystal clear: Among people under 65, nearly half of all cancer diagnoses are associated with being overweight or obese, according to research published in 2017. (And let’s remember that cancer is the second leading cause of death in the United States.)

That grim data is somewhat offset by other data published last week in the Journal of the American Medical Association. The authors found that among people severely obese – an example would be someone 5 feet 8 inches tall and about 300 pounds – weight loss reduces the likelihood of developing cancer and dying from it. But it requires a massive amount of weight loss – approximately 20-25 percent of one’s body weight.

The study’s authors were agnostic on how to lose that much weight, but they focused on people who had had bariatric surgery, which typically involves sealing off much of the stomach so it can only hold about an ounce of food.

Those individuals had shed 61 pounds while those who did not have the surgery had shed just 6 pounds. (The study followed people for an average of six years.) Among those having the surgery, slightly less than 3 percent developed cancer, while 4.9 percent of those in the nonsurgical group did.

These results are likely to generate calls to expand access to bariatric surgery. The procedure has become more common – about 256,000 such procedures were conducted in 2019, up from 158,000 in 2011. (And yes, even obese children are now getting the surgery.) But like any invasive procedure, there are risks.

Data from the American Society of Metabolic and Bariatric Surgery shows that nearly 17 percent of bariatric surgeries need to be revised (making them the third-most common type of this surgery). And other studies involving a 10-year follow-up show that for the most common form of the surgery, known as RYGB, the median reoperation rate was 29 percent. And two studies of the sleeve gastrectomy revealed a reoperation rate of 34 percent.

The study published last week makes clear that for the severely obese – nine percent of U.S. adults – bariatric surgery does provide health benefits. But the procedure is no panacea for the population at-large. As one of the study’s authors told the New York Times, “There are probably 100 million people that are obese. We cannot do bariatric surgery on a third of the U.S. population. It’s simply not feasible.”