As drugs like Ozempic and Wegovy skyrocket in popularity, some Massachusetts obesity experts warn dramatic weight loss may not be a sure ticket to perfect health.
Their concerns stem from research into a kind of hidden “muscular fat” — seen in both thin and overweight patients. This type of fat, known as intramuscular adipose tissue, is thought to play a role in diabetes, certain physical problems related to aging, and inflammation.
Researchers at Mass General Brigham and Harvard Medical School say their new study about heart risks linked to this fat raises more questions about whether weight loss drugs may cause people to overlook key measures of health, beyond pounds gained or shed.
The researchers examined patients’ body compositions to see how fat was distributed, and identified the “hidden fat” tissue. The study found that for every 1% increase in this type of fat, there was a 7% increase in the risk of major cardiovascular events, including heart attacks and heart failure.
The study, conducted at the Cardiac Stress Laboratory at Brigham and Women’s Hospital, included participants who ranged in weight. But all had experienced cardiac symptoms like chest pains or shortness of breath. The finding that patients with more hidden muscular fat were at greater risk for a major cardiac-related event suggests it’s not just the quantity, but the quality and distribution of fat, that affects cardiovascular health, the researchers concluded.
Dr. Viviany Taqueti, lead study author and director of the Cardiac Stress Laboratory, said therapies that lead to fast and major weight loss act as blunt tools, but may not target specific fat types like intramuscular adipose tissue — and may even result in the loss of precious muscle tissue.
Health is “not just about maximum weight loss,” Taqueti said. “It’s really about intentional and careful weight loss that benefits your cardiovascular health.”
The study did not focus specifically on the impacts of GLP-1 medications like Ozempic. And Taqueti added that in-depth screenings for intramuscular adipose tissue in all patients would be impractical because they are costly and time consuming. But, she said, the study supports the idea that more research is needed on GLP-1 drugs and their effect on different types of fats.
Other researchers have also called for more research into the effects of GLP-1 drugs. Dr. Dariush Mozaffarian, director of the Food as Medicine Institute at Tufts University, said Taqueti’s research is not dramatically new, but it provides another example of how the type of fat and its distribution matter more than total weight loss.
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“The issue with GLP-1s is that they do not preferentially preserve lean muscle mass. So, when people are losing weight on these drugs, they’re losing both fat and muscle, and that can have long-term metabolic consequences,” said Mozaffarian, who was not involved in the Harvard study.
More than 2,000 people start taking GLP-1 drugs each month in Massachusetts, according to the state’s largest insurer Blue Cross Blue Shield of Massachusetts, which recently announced it will no longer cover the drugs solely for weight loss, in most cases. The insurer reported spending on these medications rose by $200 million last year.
In addition to the cost, Mozaffarian said another concern is how long patients stick with these treatments. Research suggests about 65% of patients stop the medicines after one year, although the rate is lower for patients who taking the drugs for diabetes.
“This leads to a sort of weight cycling or yo-yo of weight loss. That’s what’s so dangerous with GLP-1s when weight is lost quickly,” Mozaffarian said. “You lose muscle, bone and fat.”
Mozaffarian says more research is needed into the long-term health effects of GLP-1 medications. And given their cost, he argues for an approach that takes into account multiple measures of health, including weight, blood pressure and cholesterol levels, diet and exercise.
“It’s both unethical and national economic suicide to prescribe GLP-1s without robust nutrition and lifestyle programming,” Mozaffarian said.