As GLP-1 weight loss drugs like Ozempic and Wegovy continue to grow in popularity, experts warn that rapid weight loss and severe calorie restriction could deprive the brain of vital energy and nutrients.
Dr. Tommy Wood, a professor of pediatrics and neuroscience at the University of Washington, said the effects of medications on the brain may depend on whether the body gets enough energy and nutrients during weight loss.
“The best way to think about it is the spectrum of what we call energy availability,” Wood told Fox News Digital at Strong NY, New York City’s largest annual fitness and wellness festival. “The brain is the most energy-intensive organ in the body.”
According to Wood, brain reserve – the physical amount and integrity of brain tissue – follows a bell-shaped curve relative to the body’s energy availability.
Excess energy caused by obesity, high blood sugar and metabolic diseases can reduce brain resilience by damaging blood vessels and contributing to insulin resistance.
In these cases, GLP-1 medications may provide cognitive benefits by lowering blood pressure and improving blood sugar control.
However, Wood noted that the lower end of the energy spectrum presents its own structural risks to the brain. Because the brain relies heavily on continuous fuel, extreme caloric deficits can force the organ to consume its own tissues.
“There was a study that looked at the brains of people who ran a marathon…because marathoning is very energy-intensive, the white matter in the brain actually decreased during a marathon because the brain didn’t have enough energy…so it was eating its own white matter,” Wood said, noting that participants’ brains recovered after resting and refueling.
“It just shows that the brain is really energy hungry and will shrink in size if it doesn’t get enough.”
Muscle quality
Concerns about losing lean muscle mass when taking GLP-1 drugs are often nuanced, Wood said. Some of the “lean mass” lost is actually fat that has accumulated inside the muscles.
“So technically your muscles are shrinking, but you’re not getting weaker,” he told Fox News Digital. “And the quality and function of your muscles actually improves.”
However, risks arise when people taking GLP-1 medications significantly reduce their food intake for prolonged periods. Chronic undernutrition can deprive the central nervous system of essential structural nutrients, Wood warned.
“It’s possible you’re going too far,” he said. “If you’re not eating enough, you’re not getting essential nutrients to the brain. So you’re not getting enough omega-3 fatty acids, which we know are very important. You’re not getting enough iron and protein and all that kind of stuff.”
Protecting the brain during weight loss
To maintain brain health while losing weight, Wood recommends pairing weight loss diets with resistance training twice a week to maintain functional muscle mass and stimulate brain growth factors.
Additionally, Wood says, ensuring adequate intake of basic “neuronutrients” — including B vitamins (B12, folate, B6), vitamin D, iron and omega-3 fatty acids — prevents long-term cognitive impairment.
“For most people, I think it’s going to be beneficial to start with, but you just have to make sure you don’t go too far, and that you’re getting enough of everything the brain needs,” he advised.
Gn Health
