What Is Normal Weight Obesity—and Why Can’t Ozempic Help?

In 2020 more than 40 percent of Americans reported experiencing weight stigma, not only from friends and family members but also from their nurses and doctors. Whether the issue is scoliosis or cancer, patients often find that their health care professionals can’t see beyond their obesity, and their concerns are drowned out by tired demands of weight loss. The doctor’s office, in turn, becomes yet another untrustworthy place to seek help.

Fatphobia is undoubtedly pernicious, and we believe that its perils are broader than generally recognized. Just as many presume that people with obesity are unhealthy, the same bias reinforces that people of normal weight must be healthy, contributing to the neglect of hypertension, diabetes, and other metabolic diseases in which the body’s ability to process energy and nutrients malfunctions. These diseases, due to fatphobia, are too often assumed to affect only people with visible fat, so today’s Health at Every Size movement tries to address this issue by suggesting that all body types can be healthy. But the inverse is also true: All body types can be unhealthy. Thin people can harbor fat that threatens their well-being. And for those people, weight loss isn’t the answer.

Body mass index, a metric that tries to assess body fat using height and weight, is well known for its inaccuracies and biased methodology. For instance, Hispanic and Asian people with seemingly normal BMIs are more likely to have obesity—taking the form of fat deeper in their bodies—than white people are. South Asians in particular are prone to high blood pressure and Type 2 diabetes regardless of weight, and on average, heart disease strikes them a decade earlier, with 40 percent increased mortality. One factor driving these health disparities might be diagnostic overshadowing, in which one visible condition obscures other clinically relevant signals. In other words, doctors might overlook that their thin patients can still get sick with metabolic diseases.

Having a normal BMI with high body fat levels is called “normal weight obesity.” It affects 30 million Americans—nearly 10 percent of the population—although researchers believe that this number may be on the rise. Several studies emphasize this condition’s ability to go unrecognized and untreated, due at least partially to its murky diagnostic criteria.

Experts point to the difference between subcutaneous and visceral fat as a reason BMI underestimates obesity in some groups. Subcutaneous fat is under our skin, the kind we can all see; however, visceral fat covers our internal organs, like the liver, pancreas, and intestines. Although too much of either kind of fat can be problematic, visceral fat—the type we can’t see and a small fraction of total body fat, adding negligible amounts to our weight—especially increases one’s risk of metabolic disease.

Normal weight obesity might be tricky to detect, but there are ways. One indicator, for example, is an abnormal adipokine ratio, which refers to the molecules secreted by visceral fat cells to help regulate metabolism; a simple blood test can check for this. Another emerging lab test is the cardiometabolic index, which assesses a patient’s waist size–to–height ratio, “good cholesterol” levels, and ratio of triglycerides—a type of fat found in the blood. With these different diagnostic signals, doctors can better detect normal weight obesity early.

The problem is that doctors might sign a clean bill of health without knocking around or conducting these tests because patients with normal weight obesity can appear to be physically fit. Preventive measures and lifestyle counseling, in turn, may be neglected even though they promote health and well-being for everyone, whatever their body shape.

We are both of South Asian descent and, looking at our own families, you can find every kind of metabolic disease within a few generations, including one skinny uncle who nearly died of a heart attack at age 44. He can’t remember a time a doctor talked to him about improving his diet and exercise, let alone broached the topic of heart disease—themes that, for fat people, can dominate medical visits to the exclusion of other issues. The double standards regarding obesity benefit nobody.

It’s true that BMI can serve as a loose signal for metabolic disease risk and that excess weight is associated with worse health outcomes. But we have allowed this rule of thumb to shape individual treatment plans. Health care practitioners do their best work when they look at patients as a whole, considering all the numbers, from insulin to blood pressure to cholesterol levels to liver function tests. This deeper understanding is generally reassuring for patients—that their doctors see them as a person rather than just a number on the scale.

Such holistic attention is crucial to identify normal weight obesity. Doctors should assess thin patients’ risk by specifically looking for a family history of metabolic diseases. An additional step could include estimating visceral fat through a bioelectrical impedance weighing scale, which passes a small electrical current through the body to estimate fat quantities; it’s cheaper but admittedly less precise than full-body imaging scans.

Treating normal weight obesity could also be simpler than addressing typical obesity. Although diet and exercise are important for health, they seldom achieve sustained weight loss, with an estimated 80 percent of efforts failing after a year. But for patients with normal weight obesity, that’s actually OK: They don’t need to lose weight. Just fat.

So, rather than Ozempic, Zepbound, and other GLP-1 drugs that cause 15–21 percent weight loss, a Mediterranean diet and intense aerobic exercise might be treatment enough, with research showing that these interventions lower visceral fat with little effect on subcutaneous fat. Doctors just need to more consistently recommend these lifestyle changes for normal weight obesity, instead of so quickly stamping thin patients with a clean bill of health. Down the road, perhaps someone will invent an Ozempic that doesn’t cause patients to shed so many pounds, maintaining the drug’s benefits to metabolic health independent of weight loss.

All of us, not just physicians and pharmaceutical companies, can play a part. Our culture is obsessed with thinness, enamored with the aesthetics of smaller bodies, so changing cultural perceptions inevitably requires broad social advocacy and political will. The standard-bearers of weight-inclusive efforts have long been people with excess weight—and understandably so. But in a world where weight has become a cheap heuristic for health, fatphobia threatens us all.