23:01 2 October, 2026As GLP-1 weight-loss drugs, including Ozempic and Wegovy, continue to surge in popularity, experts are warning that losing weight too quickly and severely restricting calorie intake could deprive the brain of essential energy and nutrients.
According to Tommy Wood, a professor of pediatrics and neuroscience at the University of Washington, the effects of these medications on the brain depend to a large extent on whether the body receives enough energy and nutrients while losing weight.
“The brain is the most energy-demanding organ in the body,” the expert told Fox News Digital.
Wood explains that brain health is closely linked to energy availability. In people with obesity, high blood sugar and metabolic dysfunction, excess energy can also have harmful effects on the brain by damaging blood vessels and contributing to insulin resistance. In such cases, GLP-1 medications may, on the other hand, offer benefits by lowering blood pressure and improving blood sugar control.
However, an excessive calorie deficit can create a different problem. According to the specialist, when the brain does not receive enough fuel, the body may temporarily begin using its own tissues.
Wood cited a study of athletes in which participants experienced a temporary reduction in the volume of the brain’s white matter after running a marathon because of the enormous energy demands placed on the body. After rest and adequate nutrition, their measurements returned to normal.
Another concern is the loss of muscle mass. The expert notes that in the early stages of weight loss, some of what is classified as “lean mass” may actually consist of fat stored within the muscles. As a result, muscles may become smaller without necessarily experiencing a decline in strength or function.
The risks increase if people taking GLP-1 medications spend prolonged periods eating too little. The body may fail to receive essential nutrients needed for brain health, including protein, iron and omega-3 fatty acids.
To reduce these risks, Wood recommends combining weight loss with strength training approximately twice a week. According to the expert, this can help preserve functional muscle mass and stimulate the production of factors that support brain health.
It is also important to consume sufficient amounts of so-called brain-supporting nutrients, including B vitamins, vitamin D, iron and omega-3 fatty acids.
“For most people, these medications can be beneficial, but it is important not to go too far and to make sure the body is getting everything it needs for the brain to function properly,” Wood emphasized.