Should Everyone Be Taking GLP-1s?

(Editor’s Note: As GLP-1 weight-loss medications reshape obesity treatment, important questions remain about their long-term effects, affordability and appropriate use. This article draws on a discussion featured in The Harvard Gazette on Oct. 21, 2026, hosted by Harvard Staff Writer Samantha Laine Perfas on the university’s Harvard Thinking podcast, featuring insights from three experts in obesity medicine and evolutionary biology.)

CAMBRIDGE, MA–GLP-1 medications have transformed the treatment of obesity, helping patients lose substantial amounts of weight and challenging long-held assumptions that obesity is primarily a matter of willpower. But as their popularity grows, Harvard-affiliated experts say important questions remain about who should receive the drugs, what happens when patients stop taking them and whether the focus on medication is distracting from the underlying causes of the disease.

Those issues were explored in a recent episode of Harvard Thinking, a podcast produced by Harvard University and featured in The Harvard Gazette on Oct. 21. Hosted by Samantha Laine Perfas, a Harvard Staff Writer, the discussion brought together Caroline Apovian, a professor of medicine at Harvard Medical School; Daniel Lieberman, a professor of human evolutionary biology at Harvard University; and Fatima Cody Stanford, an obesity medicine physician-scientist at Mass General Brigham and an associate professor of medicine and pediatrics at Harvard Medical School.

The conversation examined both the promise of glucagon-like peptide-1 receptor agonists, commonly known as GLP-1s, and the medical, economic and public-health challenges associated with their expanding use.

According to the discussion, nearly one in eight American adults was using GLP-1 medications for weight loss as of 2025. Originally developed to treat Type 2 diabetes, the drugs have become increasingly prominent in obesity treatment and are also being studied for potential applications in other conditions.

For patients with obesity, the medications can reduce appetite and persistent thoughts about food, sometimes described as “food noise.” They can also help patients feel full sooner and make changes in eating habits and physical activity more manageable.

Apovian, co-inaugural director of the Integrated Mass General Brigham Center for Weight Management and Wellness, said the medications represent a significant advance in obesity medicine because they address biological mechanisms involved in the disease.

For some patients, she explained, the effects go beyond weight loss. They report that their preoccupation with food diminishes, making it easier to change their eating habits and become more physically active.

Stanford said the medications are also changing public understanding of obesity by demonstrating that the condition involves biology rather than simply a lack of discipline or self-control.

She described their development as an inflection point in the treatment of a disease that has long been misunderstood and stigmatized.

Yet the experts cautioned against treating the medications as a universal solution.

Who should receive the drugs?

One of the central questions raised in the discussion was whether GLP-1 medications are being prescribed to the patients who need them most or increasingly being used by people seeking relatively modest cosmetic weight loss.

Apovian argued that medical guidelines should prioritize patients at the highest risk from obesity and related health complications.

“I think what we’re not talking about adequately enough is: Who are they for?” said Caroline Apovian, professor of medicine at Harvard Medical School and co-inaugural director of the Integrated Mass General Brigham Center for Weight Management and Wellness.

She warned against using the medications simply to lose a few pounds without a medical indication for obesity treatment.

“If you take a GLP-1 to lose 10 pounds, you don’t have the disease of obesity,” Apovian said in the discussion, cautioning that some people could face weight regain after discontinuing treatment.

The concern is particularly relevant as social media and commercial marketing have helped turn GLP-1 medications into household names. The experts said that the drugs’ growing visibility should not obscure the distinction between treating a chronic disease and pursuing short-term cosmetic goals.

They also noted that determining who would benefit most remains complicated. Body mass index, or BMI, does not directly measure body fat or fully capture an individual’s health risks, Apovian said, underscoring the need for better methods of identifying patients who require more intensive treatment.

Muscle loss and the risks of rapid weight reduction

Another concern discussed by the panel was the loss of muscle that can accompany substantial weight reduction.

Daniel Lieberman, a professor of human evolutionary biology at Harvard University and author of the book Fed Up: What Evolution Reveals About Food, Diet, Health, and Eating Well, said some patients lose significant amounts of fat-free mass while taking GLP-1 medications.

That matters because fat-free mass includes muscle and other tissues that are important for strength, mobility and overall health. For older adults, excessive muscle loss can contribute to frailty and sarcopenia, the age-related loss of muscle mass and function.

Lieberman said patients losing substantial weight should pay attention to strength training and the preservation of muscle, particularly as they age.

Apovian agreed that muscle loss deserves attention but emphasized that some loss of lean tissue is expected with weight reduction, whether it occurs through medication, bariatric surgery or lifestyle changes. The proportion of muscle lost may vary with factors such as the speed of weight loss, protein intake and physical activity.

Fatima Cody Stanford, an obesity medicine physician-scientist at Mass General Brigham, likewise highlighted the importance of preserving muscle, especially among older patients.

She said treatment should involve a broader approach to physical activity rather than concentrating exclusively on cardiovascular exercise. Strength training and adequate nutrition are important considerations for patients undergoing significant weight loss, she argued.

The concern could become more pressing as access to obesity medications expands among older adults, who are already more vulnerable to muscle loss and falls.

The affordability problem

The panel also raised concerns about what happens when patients can no longer afford medication or lose insurance coverage.

In the discussion, Stanford said cost and access were major reasons patients discontinued GLP-1 treatment. She described changes in insurance coverage in Massachusetts, where some employer-sponsored plans had stopped covering the medications for patients with obesity as of Jan. 1, 2026.

For patients paying out of pocket, she cited monthly costs of roughly $300 to $450, a substantial expense for many households.

Discontinuation can have serious consequences for some patients, the experts said, because appetite and weight may increase again after treatment ends.

Apovian described a patient who had lost 100 pounds while taking tirzepatide, marketed as Zepbound, in preparation for bariatric surgery. After the medication became unavailable to him, she said, he began regaining weight, prompting her to urge the surgical team to move forward with treatment.

The example illustrates a broader challenge: If obesity is managed as a chronic disease, patients may need long-term treatment, yet the affordability and availability of medications can change.

For patients who have achieved substantial weight loss, an interruption in access can undermine progress and complicate subsequent treatment.

Obesity is not simply a matter of willpower

The discussion also examined why obesity has become so prevalent and why it is difficult for many people to lose weight and maintain that loss.

Lieberman offered an evolutionary perspective, arguing that humans developed biological mechanisms that favor storing energy and resisting weight loss. In environments where food was scarce, those mechanisms helped people survive.

Modern food environments, however, have changed dramatically. Highly processed foods that are calorie-dense and easy to consume are widely available, while social and economic conditions can influence eating habits, stress and opportunities for physical activity.

Lieberman said the rapid rise in obesity cannot be explained by genetic changes alone. Instead, it reflects interactions among biology, food environments, metabolism, physical activity and other factors.

Stanford added that the social and historical dimensions of obesity also require attention. She discussed the disproportionate burden of obesity among Black women in the United States and argued that chronic stress, racism and historical inequalities must be considered alongside dietary and biological factors.

Lieberman agreed that obesity is multifactorial, noting that chronic stress and socioeconomic conditions can influence health.

The discussion reinforced the experts’ view that medication can treat important biological mechanisms without eliminating all the environmental and social factors that contribute to obesity.

Treatment versus prevention

Despite their concerns, the experts did not argue that GLP-1 medications should be dismissed or that they can simply be replaced by conventional advice about diet and exercise.

Stanford said many patients who seek specialist treatment have already tried numerous weight-loss programs without achieving lasting results. For some, medication can make physical activity and healthier eating habits more achievable.

Apovian similarly argued that obesity should be understood and treated as a disease rather than a personal failing.

But Lieberman warned that the success of medications could divert attention from prevention if policymakers, companies and consumers focus exclusively on pharmaceutical solutions.

“My real nightmare about GLP-1s is that we end up in a world where we cease to pay attention to the cause of the problem,” said Daniel Lieberman, professor of human evolutionary biology at Harvard University.

He argued that reducing obesity rates over the long term will require addressing the conditions that contribute to weight gain, including the modern food environment.

The experts also discussed the potential use of GLP-1 medications in children and adolescents. Stanford said some young patients with obesity have significant metabolic health problems and can respond well to treatment. Lieberman, however, emphasized the importance of preventing obesity from developing in the first place.

The panel’s broader message was that treatment and prevention need not be competing approaches. Medications can offer meaningful benefits to patients who need them, while public-health efforts can address the conditions that contribute to the disease.

As research into GLP-1s continues, scientists are also examining possible applications beyond obesity and Type 2 diabetes, including neurological and inflammatory conditions. The experts said those developments could expand the drugs’ role in medicine, although further research will be needed to establish their benefits and appropriate uses.

For now, the questions are not simply whether GLP-1 medications work. They are how to identify the patients most likely to benefit, how to manage the risks of treatment, how to ensure continued access and how to prevent obesity in a society where the conditions that promote weight gain remain widespread.

As the discussion in The Harvard Gazette makes clear, the drugs may be changing obesity treatment, but they have not eliminated the need to understand the disease itself.