When did obesity become a drug deficiency?

Look at almost any photograph of an American crowd taken 60 years ago. It can be a baseball game, a high school graduation, a beach, an airport terminal, a factory floor, or simply people walking down a city street. Something is immediately noticeable to modern eyes, although almost nobody in the photograph would have considered it remarkable: most people are relatively thin.

They did not have continuous glucose monitors, smartphone applications that counted calories and macronutrients, wearable devices reminding them to stand, boutique fitness studios, bariatric surgery centers, or medications capable of producing 15 or 20 percent reductions in body weight. They were not necessarily more virtuous than we are, and they certainly did not possess superior genes. They lived in a different metabolic environment.

The data backs up what we see in those old photos. In the early 1960s, about 13 percent of American adults were obese. By August 2023, that number had jumped to 40.3 percent, with another 31.7 percent considered overweight and nearly one in ten classified as severely obese.[1] This trend isn't just in the United States. A huge study of over 220 million people from 200 countries found a dramatic global rise in obesity between 1990 and 2022.[2] Our genes haven't changed much in that time. Something else has.

We're now at a turning point in medicine. Faced with one of the biggest and fastest changes in human health, we're treating the results as a condition that needs lifelong medication. The newest drugs are very effective, and that's important to recognize. Semaglutide and tirzepatide have led to weight loss that older nonsurgical treatments rarely matched.[3,4] Semaglutide has also reduced the risk of major heart problems in people with overweight or obesity and heart disease who didn't have diabetes.[5] Tirzepatide has greatly improved sleep apnea in people with obesity.[6] These results are significant, and these drugs are much more than cosmetic weight-loss aids.

That's why we need to look closely at what's happening now. The problem isn't that these drugs don't work; they clearly do. The real concern is that they might work so well that we stop asking why so many people need them in the first place. We could be seeing a major medical breakthrough, but at the same time, we might be accepting that the effects of an unhealthy environment should just be managed with medication. The real question isn't whether these "GLP-1" drugs are effective. It's whether their success is making us stop looking for the root causes of the obesity epidemic.

The epidemic that became a diagnosis

For decades, obesity was framed largely as an individual failure. The explanation was simple: people ate too much, exercised too little, and lacked the discipline necessary to change. That view was scientifically inadequate and often cruel. Body weight is influenced by genetics, neuroendocrine signaling, appetite regulation, insulin sensitivity, adipocyte biology, medications, sleep, psychological factors, socioeconomic conditions, physical activity, and environmental exposures. Contemporary medicine appropriately recognizes obesity as far more complicated than failure of willpower.

Recent international efforts have gone even further, distinguishing excess adiposity from clinical obesity and emphasizing the actual effects of adiposity on organ and tissue function rather than relying exclusively on body mass index.[7]

It was important to stop blaming people for obesity. But now, medicine might be swapping one simple explanation for another. Just because obesity is a real biological condition doesn't mean it starts inside each person. A disease can be both real and caused by the environment. For example, asthma from air pollution is still asthma, and lead poisoning is still a real illness even if the cause is environmental. If a whole community gets sick after a change in the water supply, doctors treat the patients, but no one thinks the community suddenly developed a genetic problem.

We should be just as curious about obesity. When a condition becomes much more common in just a few generations, our first question should be: what has changed in our environment, habits, or society to cause this? Instead, the focus is quickly shifting to which drug can best fight it. We changed the world around us, saw people's bodies change in response, and now we're treating those changes as the main problem.

There is another change that occurred alongside the biological one: our culture gradually changed its definition of what was normal. I have written about this before, using the transformation of Victoria's Secret as one highly visible example. The famously thin "Angels" who once defined the brand were eventually replaced by models representing a much broader range of body sizes, part of a larger and understandable effort to move away from unrealistic beauty standards and the humiliation of people because of their weight.[8] There was much about that change that was humane and necessary. No person should be shamed, ridiculed, or assigned less dignity because of body size.

But compassion and normalization are not the same thing. As obesity became progressively more common, society did more than become more accepting of people with obesity; it also became increasingly reluctant to acknowledge obesity itself as abnormal. The distinction matters because one can respect every human body while still recognizing that excess adiposity carries important medical consequences.

In a remarkably short period, we changed the food environment, changed the physical environment, watched the population become heavier, and then changed the cultural image of what a normal body looked like. Now we are entering the next stage of that progression: pharmacologically treating the metabolic consequences.