Three-quarters of Americans are now classified as overweight or obese, according to a recent study in The Lancet. Breakthrough anti-obesity medications like Ozempic have transformed the treatment of obesity-related conditions, and President Joe Biden has proposed expanding access to these therapies.

However, Robert F. Kennedy Jr., President-elect Donald Trump’s nominee for the nation’s top health role, has expressed skepticism about these medications. He argues that diabetes and obesity could be resolved “overnight” by simply providing people with three nutritious meals a day.

USC experts say it’s a complicated issue. Researchers recently weighed in on the biology of overeating, the challenge of finding healthy foods and the potential public health benefits of medications like Ozempic.

Healthy food is hard to find

“People with high incomes can easily access convenient, healthy foods via delivery or pre-prepared options,” said Kayla de la Haye, director of the Institute for Food System Equity at the Center for Economic and Social Research at the USC Dornsife College of Letters, Arts and Science. “But a quarter (26%) of L.A. County residents struggle with food insecurity, and a quarter live in ‘food deserts,’ areas with limited access to affordable, healthy food.

“The root causes of poor diets are systemic issues, including food and nutrition insecurity, unhealthy food marketing and an unhealthy food system that makes accessing nutritious food difficult, if not impossible, for many.”

The biology behind excessive eating

USC Dornsife’s Scott Kanoski studies the biological systems that underlie excessive eating behavior contributing to obesity, as well as what certain diets do to our brains.

For example, one study found that rats fed a diet full of fat and sugar in adolescence suffered memory impairment. Another recent study showed that oxytocin, a hormone produced in the brain, promotes excessive food intake, particularly when dining with friends and family. On the other hand, another hormone — GLP-1 — helps regulate blood sugar, appetite and digestion.

“Ozempic and other GLP-1-based drugs have revolutionized diabetes and weight loss therapy,” said Kanoski, a professor of biological sciences.

“While bariatric surgeries like gastric bypass are still the most effective approaches for appetite control and weight loss, newer drugs that target GLP-1 in concert with other gut hormones are emerging as the future of obesity treatment.”

A new era in managing obesity — but for whom?

“I’ve seen firsthand how effective new anti-obesity medications can be in any community when paired with proper medical guidance,” said physician Anne Peters, director of the USC Clinical Diabetes Programs. “Expanded public coverage of these medications can enhance public health.”

Indeed, broad access for Ozempic and similar medications could significantly lower the nation’s health care costs, according to a white paper by scholars at the USC Schaeffer Center for Health Policy & Economics.

Research by Dima Qato, director of the program on medicines and public health at the USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, found that most of the people benefiting from anti-obesity medications are those with private insurance — meaning that many individuals on Medicare and Medicaid may be missing out.

“That raises important equity concerns, given the disproportionate impact of diabetes and obesity on Black and Latino populations in these public programs,” Qato said.

Exercise in a pill for people who have trouble moving

Exercise is important for burning off holiday calories, but it’s also essential for healthy brain aging. Constanza Cortes of the USC Leonard Davis School of Gerontology studies the chemical messengers secreted during physical exertion that seem to protect against cognitive decline. But what about people who can’t move because of medical conditions?

Cortes recently demonstrated that a muscle-messaging peptide given to mice via injection benefited their brains — without exercise.

“This is specifically to activate these brain pathways that respond to exercise in the context of populations that can’t exercise,” Cortes said. “It’s for people who cannot get on the treadmill and exercise to the level that they need to.”