Ditch the scale and focus on fitness, experts say

By Melanie Radzicki McManus

(CNN) — People in the United States are obsessed with dieting and body size. That may be due to the fact that 40.3% of adults have obesity today, according to the US Centers for Disease Control and Prevention.

The weight loss industry likely contributes to these twin obsessions, as the global weight loss and diet management market size was worth about $143 billion in 2022, and is projected to soar to roughly $299 billion by 2030. And with more than 15 million Americans now losing weight with GLP-1 drugs that were originally created to treat type 2 diabetes, there is even more emphasis on weight.

Yet if the goal is improving your health and longevity, experts say your attention should be on fitness, not the numbers on the scale or the image you see in the mirror.

“We know so many ways to make people healthier other than weight loss,” said Dr. Lisa Erlanger, clinical professor of family medicine at the University of Washington in Seattle. Erlanger is also president of the Association for Weight and Size Inclusive Medicine. “Just increasing your steps or increasing your muscle strength, when done long-term, can reduce your chances of cancer, depression and diabetes, in addition to your risk of cardiovascular disease and all-cause mortality.”

Boosting your physical activity to improve your cardiorespiratory fitness and health — and not dieting — is definitely the better option, according to one 2024 meta-analysis. That research found people typically can’t keep off the weight over the long term, so the improved health outcomes associated with weight reduction are lost.

Researchers can’t definitively explain why so many people are overweight today, too, so reducing your caloric intake may not even work. You can also make some positive dietary changes, such as upping your intake of fruits and veggies, that will benefit your health even if the number on the scale doesn’t budge.

The current obesity epidemic began around 1980, according to Glenn Gaesser, a professor of exercise physiology at Arizona State University in Phoenix and coauthor of the 2024 meta-analysis mentioned above. Some research suggests our beefier bodies are due to larger portion sizes, too much sugar, too little activity and, more recently, ultraprocessed foods. But it’s a lot more complex than that.

“Our environment has changed with regards to our exposure to chemicals, like plastics, pesticides and herbicides,” Gaesser said. “A lot of these ‘forever’ chemicals have an effect on our endocrine system that can affect our energy balance.” Human-made “forever” chemicals — called PFAS, or perfluoroalkyl and polyfluoroalkyl substances — don’t fully break down in the environment.

Viral infections may also be a factor, according to Gaesser. Human adenovirus 36, for example, has been associated with obesity in numerous studies. Adenoviruses are common and typically cause mild symptoms such as a fever, sore throat and pink eye (conjunctivitis).

“It’s a lot bigger picture than people would like to believe,” Gaesser said. “Obesity is not just the difference between energy in and energy out.”

Dieting doesn’t work over the long term

Dieting is also largely unhelpful, Erlanger noted.

“One thing that raises body sizes without a doubt are attempts to lose weight,” Erlanger said.

Estimates vary, but it’s believed that more than 80% of people who lose a substantial amount of weight regain it within five years.

That’s because bodies have a generally set weight range and shape, based on factors such as genes and ethnicity, both Erlanger and Gaesser noted. Humans are also biologically programmed to survive periods of starvation and stress, Erlanger said. When you eat less than your body needs to maintain its weight and various functions, your metabolism decreases to ward off starvation. Your brain becomes more anxious, too, so you sleep less soundly and begin to crave more caloric foods.

“All of the things we blame fat people for — being lazy, preferring junk food — that is what their body is telling them to do,” Erlanger said. “They’re not falling off the wagon. Their body is just trying to survive.”

Thanks to the emphasis on thinness in American society, people who lose weight and then gain it back will often try another diet, and then another, continuously adding and shedding pounds. But such weight cycling —sometimes referred to as yo-yo dieting — is devastating, Erlanger said, both psychologically and physiologically.

Numerous studies link weight cycling with dozens of adverse health outcomes, including cardiovascular disease, vascular dysfunction, bone fractures, diabetes and an increased risk of certain cancers, according to Gaesser.

Focus on fitness, not fat

To best care for your body, concentrate more on motion rather than the contents of your dinner plate. Go for a bike ride or hike. Dance. Garden. (Always first consult with your physician and stop immediately if you experience pain.)

“The research is definitive — if you want to improve your health you shouldn’t diet, you should go for a walk,” Erlanger said. “But more people want to be smaller, not healthier.”

Yet your health always should be your main concern. So before latching onto the latest diet fad, take a deep breath and head outside instead. Your body, and mind, will thank you.

“Exercise is phenomenally effective in improving your health,” Gaesser said. “Every cell in your body is positively affected by exercise. You can be fit and healthy, even if your weight is not considered optimal.”

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