Anti-Obesity Drugs Complicate the Debate Over “Health at Every Size”
November 15, 2023
A 40-year-old woman visits her personal primary care physician because of fever, cough, and sore throat. While there she is weighed, her blood pressure taken, and blood samples obtained. Her body mass index (BMI)—weight divided by height squared—is 30, the medically accepted cutoff for obesity. Her blood pressure is normal and subsequent blood test results show she does not have diabetes (normal blood glucose and hemoglobin A1c levels) or elevated lipid levels (normal cholesterol and triglycerides). She is concerned about her weight, has tried many different diets and exercise regimens without success, and asks her doctor if she could take one of the new anti-obesity drugs. What should her doctor tell her?
By BMI criteria, roughly two-thirds of U.S. Americans are overweight or obese, with rates of obesity higher among non-Hispanic Black, Hispanic, and Mexican American adults than in non-Hispanic White adults. There is firm evidence that on a population level, overweight and obesity increase the risk of many adverse health outcomes and diseases, including type 2 diabetes, heart disease, some cancers, and liver disease. Overweight is a major risk for developing type 2 diabetes and one recent study showed “that each additional decade of type 2 diabetes shortens lives by about 3.5 years compared to having no diabetes.” It would seem to make sense that losing weight if one is overweight or obese is a good idea.
BMI: A Very Flawed Measure
A closer look at this assumption, however, makes the picture much less clear. The very method of classifying people as overweight or obese—calculating the BMI from weight and height—is problematic. It turns out that the BMI measure was actually developed about 200 years ago by a Belgian scientist who was trying to define the “average man.” This work “had a role in the origins of eugenics.” As McKenzie Prillaman recently wrote in the journal Nature, it was not until 1972 that the American physiologist Ancel Keys proposed to use BMI as an indicator of healthy body size. “BMI does correlate with the risk of death at the population level,” Prillaman explains, “the risk is elevated at the low end of the BMI spectrum, at which a person is considered underweight, decreases in the middle and gradually upturns again at the higher end, at which the overweight and then obesity categories lie.”
Yet it is now understood that BMI doesn’t actually measure body fat, the real culprit in raising risk for adverse health outcomes. Furthermore, the BMI norms now in use were developed almost entirely with samples of White European males and may not be accurate when applied to women and people of other ethnic and racial groups. Importantly, there are many people with a BMI over the cutoffs for overweight and obesity who are entirely healthy on many measures reflecting risk for heart and other diseases, like blood pressure and glucose and lipid levels. Such people are said to have healthy cardiometabolic status and no other complications from being overweight like joint pain.
Why, then, should we tell the woman described at the beginning of this commentary to lose weight? By all measures she is in good cardiometabolic health, yet she asks her doctor for a prescription to help her lose weight. In this case, is her wish a purely cosmetic one?
Weight Stigma and Discrimination
Overweight and obese people face significant stigma and discrimination in Western societies. Notions of what an “ideal” body should look like lead to “fat-shaming,” particularly directed against women. Mental health complications from being overweight or obese are well-described. The Health at Every Size (HAES) movement focuses attention on health rather than weight, arguing that dieting and exercise generally don’t work for long-term weight reduction maintenance and that a better approach is to support “body acceptance” regardless of size. There is also the reality that individuals have much less control over their weight than we might think. As Tressie McMillan Cottom recently wrote in the New York Times:
Both diabetes and obesity are conditions that are as much about social policy as they are about what people eat. Studies show that the crops the U.S. government subsidizes are linked to the high-sugar, high-calorie diets that put Americans at risk for abdominal fat, weight gain and high cholesterol. Sprawling communities, car-centered lives and desk jobs make it hard for many Americans to move as much as medical guidance thinks that we should. Under these conditions, telling people to change their lifestyle to lose weight or prevent diabetes is cruel.
These structural and societal factors that increase the risk for overweight and obesity are especially salient in the communities that have the highest rates of conventionally-defined overweight and obesity—disadvantaged and low-income communities where healthy food is hardest to obtain and physical exercise most difficult to accomplish.
Enter the New Anti-Obesity Drugs
But now a new player has entered this complicated arena, anti-obesity drugs that stimulate receptors for glucagon-like peptide-1 (GLP-1 agonists). These medications, like semaglutide (brand names: Ozempic and Wagovy) and tirzepatide (brand name: Mounjaro), produce substantial weight gain that appears to persist as long as people continue to take them. The recently published SURMOUNT-4 study showed that people taking tirzepatide (Mounjaro) lost an average of 25.3% of their body weight at 88 weeks. These drugs challenge many of the notions people have on all sides of the debate because unlike telling people to diet and exercise, they actually work. Of course, not everyone loses dramatic amounts of weight with the GLP-1 agonists, and they do have adverse side effects that make some people unable to tolerate them. In rare cases, very serious adverse side effects can occur, like pancreatitis and gastrointestinal block. But many people have already found these medications to be a safe and effective method for weight reduction. Unfortunately, they are also very expensive and therefore once again the people most affected by overweight and obesity are less likely to be able to access them, creating yet another structural problem in the obesity situation.
Not everyone is so happy about GLP-1 agonists. Returning to Cottom’s comments in the New York Times, “…these wonder drugs are also a shorthand for our coded language of shame, stigma, status and bias around fatness.” She goes on to insist that “It’s perfectly normal to live a happy, full life in a body that is above the medically recommended healthy size. Plenty of people do it and have done it. But being overweight becomes a social problem when it’s a population level statistic with a status hierarchy attached.” She believes we need to focus more of our attention on the social and structural issues that drive weight gain and weight stigma, rather than relying on medications.
That may be true, but another voice, family physician Mara Gordon, talked about what it is like to face people who are identified as obese and want GLP-1 agonist anti-obesity drug in a piece for NPR titled “I try to be a body-positive doctor. It’s getting harder in the age of Ozempic.” She writes that “There’s a large body of research showing that doctors are some of the worst offenders when it comes to weight stigma, and patients are less likely to get the medical care they need when they feel judged for their body size.” Dr. Gordon explains how she attempts to help her patients overcome weight stigma, accept themselves, and focus on good health rather than a particular body size. And yet, she concludes “I started to understand that it wasn’t my job to withhold Ozempic from my patients simply because it didn’t align with my ethos.”
Several things seem clear from this discussion of the obesity debates. First, we need better measures of health than BMI. The American Medical Association announced last June a change in policy away from reliance on BMI and recommending the use of other measures of body fat and metabolic health. The problem is that BMI is simple and cheap to calculate, whereas other measures require more equipment or blood tests and add expense. Perhaps one solution would be to do more research on BMI to improve its use as a screening tool that applies to women and people of diverse ethnic and racial groups. A finding of an elevated BMI using an improved calculation would then warrant more definitive tests of cardiometabolic health.
Second, despite the challenges, we must continue to battle against structural and societal issues that promote weight gain. U.S. food subsidy policies, for example, need serious rethinking because they deliberately favor production of unhealthy foods. It is absurd that even government-subsidized school lunches often consist of unhealthy, ultra-processed foods. Efforts must be made to make healthy food available to people living in low-income neighborhoods.
Third, we need to educate healthcare providers about the best ways to talk about weight and cardiometabolic health with their patients. Given the extensive research showing that doctors are often the worst promoters of weight stigma, it is clear that we need more medical education around overweight and obesity.
Finally, GLP-1 agonists will ultimately have to be made accessible to all people who need and want them. This will require that insurance companies cover their cost.
There is no easy answer to the question of what to tell our 40-year-old patient featured at the start of this discussion. Understanding her goals and motivations is an important part of this discussion. It is important to help her understand that at the moment her cardiometabolic health is fine and there is no clear immediate medical reason to insist she lose weight. At the same time, statistically she is still at risk to develop health problems associated with obesity in the years to come. We would still tell a cigarette smoker to quit even if they have not yet developed lung cancer, knowing that most people who smoke don’t ever develop lung cancer. That’s the way risk reduction works. The decision whether to start taking a GLP-1 agonist should be seen as part of a conversation about lifestyle, goals, fears, and motivations. No, Ozempic will not solve the many structural problems that are causing weight gain and obesity. On the other hand, it will help a lot of people reduce their risks for serious adverse health outcomes. Helping people navigate these issues without adding to weight stigma and fat-shaming is a skill society needs to acquire.