The case for getting fitter — not slimmer: Why our obsession with weight could be a mistake

By | November 7, 2019

“There is a general consensus out there that a fat person is basically a premature death waiting to happen.”

Dr. Glenn Gaesser is on the phone from Arizona State University in Phoenix, where the professor, exercise physiologist and author of Big Fat Lies: The Truth About Your Weight and Health is known for challenging the hand-wringing over obesity.

According to Gaesser, the health risks of excess weight have been exaggerated, success rates for long-term weight loss are mostly abysmal and many of the health problems associated with obesity can be “entirely resolved, or certainly greatly improved,” with simple changes in diet and exercise — even without significant, if any, weight loss.

Blood pressure, blood fats and blood sugars improve. People have less risk of depression and anxiety. “They feel better and move around more,” says Gaesser. “Their quality of life improves.”

Every year over the last several decades, 25 to 50 per cent of the American population has attempted to lose weight. Yet the prevalence of obesity has doubled over that same period. “The only conclusion is that (the focus on weight) has not worked — it literally, on a population level, has not worked,” Gaesser says. “And it’s insane to think it’s going to work in the future if we just tried a little bit harder.”

He and others argue that it’s time to dispense with the notion that excess body fat, in and of itself, is risky and that the only “cure” to avert an untimely death is weight loss. Instead, the focus should be on fitness — specifically, cardiorespiratory, or aerobic, fitness. As Gaesser and Steven Blair, a professor emeritus at the University of South Carolina, write in Medicine & Science in Sports & Exercise, the fitness of the cardiovasuclar system, lungs and muscles is a more powerful predictor of disease and death than obesity. It can also be improved, significantly, with exercise.

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“It’s far easier to get a fat person fit than it is to get a fat person slim,” Gaesser says.

A 2014 meta-analysis of nearly 93,000 people backs up the fit-fat hypothesis. It found that fit people — whether normal weight, overweight or obese — had similar survival rates. The unfit, by contrast, had twice the risk of dying from any cause during follow-up.

“Fit individuals who are overweight or obese are not automatically at a higher risk for all-cause mortality,” the authors wrote, a finding everyone, “including those unable to lose weight or maintain weight loss,” should take comfort in.  Nor was extreme exercise required: regular, moderate physical activity — 150 minutes per week of brisk walking or cycling, for example — appears to attenuate or diminish some of the negative consequences of obesity.

However, a study published in 2017 involving 3.5 million obese men and women found that even those who started off “metabolically healthy” —  free of diabetes, high blood pressure or abnormal blood fats — had an increased risk of coronary artery disease and a doubled risk of heart failure compared to normal-weight cohorts in follow-up checks five years later.

“At the population level, so-called metabolically healthy obesity is not a harmless condition and perhaps it is best not to use this term to describe an obese person, regardless of how many metabolic complications they have,” lead author Dr. Rishi Caleyachetty, of the University of Birmingham, England, said when the study was released.

Dr. Eric Ravussin, the director of the Nutritional Obesity Research Center at Pennington Biomedical Research Center in Baton Rouge, La., concurs. “I don’t believe in the concept of the metabolically healthy obese,” he says. “I think the fit, fat guy is not as healthy as the fit, lean guy.”

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So, which is it: Is fat-but-fit a myth, or are we wrong to be so hung up on weight?

Gaesser isn’t suggesting obesity is entirely benign. “Nor do we contend that we should be complacent about obesity or ignore it,” he and Blair write. But increasing fitness, they argue, is a better goal than weight loss.

For one thing, short of radical surgery to reconfigure the gut, little seems to keep weight off. According to a 2015 study published in the American Journal of Public Health, the annual probability of a person with obesity attaining a “normal” body weight was roughly one in 210 for men and one in 124 for women over nine years of follow-up. The odds increased to one in 1,290 for men and one in 677 for women with “morbid” obesity, meaning a BMI of 40 or higher.

Moreover, weight cycling — losing huge amounts of weight only to gain it back (or end up even heavier) — can be dangerous. Studies suggest that as the weight is regained, it causes fluctuations in blood pressure, heart rate and circulating levels of blood fats and insulin, increasing the risk of a heart attack or stroke.

And some weight appears protective. “The lowest mortality rates of anyone in America are those considered overweight,” Gaesser says. “So, people with a BMI of 25 to 30 have better prospective for longevity than people in the so-called normal weight or healthy weight range.”

One 2016 study using U.S. national health data, for example, found the risk of dying was lower for overweight than normal weight adults, even after adjusting for smoking and pre-existing diseases such as diabetes, cancer, cardiovascular disease, asthma and kidney disease. A study published in October found that while people who remained obese throughout their adult life had the highest risk of a premature death, remaining overweight throughout adulthood had a “very modest, or null association.”

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Gaesser speculates that people with a higher body weight may have more energy reserves to protect them in times or crisis or illness. But much of the research on the “obesity paradox” are epidemiological studies, meaning they can’t establish cause and effect, and lifestyle and other variables aren’t always factored in.

That makes weight loss a difficult goal to abandon entirely. In fact, even a modest weight reduction of four per cent of initial weight is enough to reduce the risk of diabetes by as much as 80 per cent in people at risk of the disease, says Dr. Arya Sharma, a professor of medicine and an expert in obesity and cardio-metabolic health at the University of Alberta.

Some problems require much greater fat loss. “A four-percent weight loss would not get you anything if you have sleep apnea — you would need 10 or 15 per cent,” Sharma says. One recent study published in the European Respiratory Journal found that fatty tissue builds up in the lungs of people living with overweight or obesity, which could explain why they’re more likely to suffer from wheezing and asthma.

Still, Sharma says the definition of obesity is moving to the idea that obesity is defined more by health problems and not body size. “Taken to its extreme, you can be fat, but not have ‘obesity,’” he says.

And as Gaesser points out, why set up patients for treatments that “inevitably will fail”? Better, he says, to encourage them to focus on what they can control — eating healthier and exercising more.

“Their health would improve,” he says, “though it may not make that much of a dent in the scale.”

Health – National Post