With the growing popularity of GLP-1 weight-loss medications like Ozempic and Wegovy, experts are cautioning that rapid weight loss and strict calorie restrictions could starve the brain of essential energy and nutrients.
Dr. Tommy Wood, a professor of pediatrics and neuroscience at the University of Washington, mentioned that the impact of these drugs on the brain largely hinges on whether the body maintains adequate energy and nutrient levels during the weight loss process.
“It’s helpful to think about this in terms of energy availability,” Wood shared at Strong NY, New York City’s major annual fitness and wellness event. “Your brain is the organ that demands the most energy.”
He explained that brain reserve—which refers to the quantity and integrity of brain tissue—follows a curvilinear pattern in relation to the body’s energy supply. Excess energy from obesity, elevated blood sugar, and metabolic issues can actually diminish brain resilience by harming blood vessels and promoting insulin resistance.
In scenarios of overeating, GLP-1 medications might yield cognitive benefits by managing blood pressure and enhancing blood sugar regulation.
On the downside, Wood pointed out that being at the lower end of the energy spectrum brings its own set of risks for the brain. The brain, which relies on a constant fuel supply, may start consuming its own tissue when faced with severe calorie deficits.
“There was research that observed the brains of marathon runners… during such an energy-intensive activity, the brain’s white matter actually shrank due to insufficient energy, leading the brain to literally consume its own white matter,” Wood noted, adding that the runners’ brains recovered after they rested and replenished their energy.
“This highlights how energy-hungry the brain is; it can decrease in size if it doesn’t receive enough energy,” he said.
Muscle Quality
Concerns over lean muscle loss associated with GLP-1 medications are often more complex than they seem, according to Wood. Some of the initial “lean mass” that diminishes can actually be fat stored within the muscles.
“So, while it may seem that your muscles are getting smaller, you don’t actually lose strength,” he explained. “In fact, the quality and functionality of your muscles can improve.”
However, challenges can arise when individuals on GLP-1 drugs significantly cut back on their food intake for long stretches. Wood cautioned that chronic under-eating might deprive the central nervous system of critical structural nutrients.
“There’s a risk of pushing it too far,” he said. “If you’re not eating sufficiently, you miss out on vital nutrients for the brain, including omega-3 fats, which are crucial. You also need enough iron, protein, and so on.”
Protecting the Brain During Weight Loss
To protect brain health during weight loss, Wood suggests combining weight-loss efforts with resistance training twice a week. This approach helps maintain functional muscle mass and stimulates the production of brain growth factors.
Moreover, ensuring an adequate intake of key “neuro-nutrients”—such as B vitamins (B12, folate, B6), vitamin D, iron, and omega-3 fatty acids—helps avert long-term cognitive decline, according to Wood.
“For most individuals, it’s probably a good idea to start, but just be careful not to go overboard and ensure you’re getting everything your brain requires,” he advised.
