There’s plenty of emphasis from health and fitness professionals on how excess weight affects the body — not just related to appearance, but also in terms of insulin resistance, cardiovascular effects, bone and joint health, cancer risk, metabolic syndrome and other issues — but weight can also have an effect on the brain as well.
For example, one study suggests that obesity’s links to diabetes, hypertension, depression and inflammation can all combine to raise the risk of cognitive problems for children — and those difficulties may continue into adulthood.
Does that mean losing weight makes you smarter and more mentally focused? Sorry, no. There are even some temporary brain changes during weight loss that won’t feel beneficial at all. But it’s helpful to be aware of how weight loss may play a role in how your brain is operating, and to recognize the importance of the brain-body connection.
Here’s a look at what may be happening if you’re currently dropping some weight:
You’re tracking your food on MyFitnessPal, and making super healthy choices that leave you feeling more energetic, lighter and excited about reaching your goals. But all your brain does is tell you to slow down in the bakery aisle. Is that normal?
Absolutely researchers note. In one study, researchers looked at participants who lost 10% of their bodyweight, and found they had less leptin than before the weight loss. Leptin is a hormone that signals satiety to prompt you to stop eating, and it’s released by fat cells. When you have lower overall fat, or shrink those cells down, the body responds by reducing leptin release to signal energy deficiency to the brain. Even worse, the brain responds by trying to ramp up calorie intake, making you crave fatty, high-calorie foods that cause leptin levels to surge.
When this happens, there’s a potential quick fix: Get more sleep.
“Sleep deprivation throws your leptin out of whack, and it’s not helpful for your other hormones either,” says Dr. Darria Long Gillespie, clinical assistant professor of emergency medicine at the University of Tennessee. “With sleep, exercise, lower sugar intake and stress reduction, you can help get your hormones on a better track.”
In a recent study, excess body fat was linked to lower overall brain volume, which could potentially lead to cognitive issues as you age, notes the study’s lead author, Mark Hamer, PhD, of Loughborough University in England. This effect was particularly pronounced in those study participants who carried a large amount of weight in their midsections.
That may be because your belly fat produces cytokines, small proteins involved in cell signaling that, when too abundant, can become inflammatory. If that happens, it can have a negative effect on different types of neurotransmitters, and that may lower brain volume Hamer says. Although more research needs to be done to determine the degree to which losing weight can increase volume, he adds, ditching the excess weight can bring inflammation levels down, and that likely has an effect on overall brain volume.
If you’re losing weight because you’re incorporating cardiovascular exercise into your routine, that can also increase brain volume, according to Matthew Capolongo, NASM performance enhancement specialist and a coach at New York-based Professional Athletic Performance Center. He notes that this type of exercise has been linked to more brain volume, especially from high-intensity activity.
“With more brain volume, you may have a greater ability to do complex tasks, problem solving and information processing,” he says, adding that you’ll also be increasing the size of your hippocampus, the part of the brain responsible for memory and learning.
In a small study done on women who lost weight as a result of bariatric surgery, researchers found participants did better on executive function tests compared to performance on the same tests before surgery. That means they were more adept at planning, strategizing and organizing.
The results are likely related to how the women metabolized sugar at a higher rate in their brains than those who were at a lower weight, according to one of the study’s authors, Dr. Cintia Cercato, of the University of Sao Paulo. Once they’d lost weight post-surgery, the participants’ brain metabolism rates shifted to a lower, more normal, level.
Dr. Cercato emphasizes that the women didn’t lack executive function skills before — their brains simply had to work harder when they were carrying more weight. That means weight loss became a kind of tune-up that let their brains operate more efficiently.
In general, the mechanisms involved in the brain-body connection can be complex, but one thing is clear: Losing weight affects how you think, remember and process information.