Intermittent Fasting May Support Brain Health

Fasting may improve brain function and reduce inflammation, studies show

Beth Howard

Updated December 16, 2025

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Eating healthy food is crucial for brain health. A growing body of research suggests that intermittent fasting, a timed pattern of not eating, may be a powerful way to support brain health as well.

Many studies have shown that fasting for a long block of time — say, after dinner ends at 7 or 8 p.m. until around 11 a.m. the next morning — can boost weight loss and support heart health. Now, laboratory studies suggest that fasting for a long block of time may also benefit brain cell function and reduce risks to brain health, such as inflammation and high blood sugar.

Clinical trials are testing these benefits in people with encouraging results. In one eight-week study, reported in 2024 in Cell Metabolism, that compared intermittent fasting to a low-calorie diet in 40 older adults with a mean age of 63, the fasting plan improved memory and executive function more than a low-calorie diet.

Emerging research also suggests that fasting may improve brain function, reduce inflammation and ease symptoms in people who have mild cognitive impairment, per a 2025 review in The Journal of Nutrition, Health and Aging.

That said, intermittent fasting may not be for everyone. It carries risks for older adults, especially those with existing health conditions.

Promoting brain growth, reducing inflammation

Intermittent fasting may support brain health in a number of ways. Here’s how it works: When you fast, your body uses up its stored blood sugars and starts burning fats called ketones for energy. These changes signal the brain to ramp up production of a protein called brain-derived neurotrophic factor (BDNF). It’s the same superpower chemical the brain produces when you exercise.

BDNF supports brain cell function in the hippocampus, the brain region that is the seat of memory and learning. It also protects cells and promotes neuroplasticity, your brain’s ability to adapt and change.

Fasting can also reduce inflammation and may help regulate blood sugars and improve cholesterol levels, per a 2025 review of eight randomized controlled trials of 573 participants, total, published in the Journal of Health, Population and Nutrition. And what’s good for heart health is good for brain health.

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It’s when you eat, not what

Intermittent fasting isn’t about excluding specific food groups, such as carbohydrates, fats, sugar or animal proteins. Yet, it can lead to weight loss, lower blood pressure and improved blood sugar regulation, according to a review of research published in 2024 in Microbial Physiology.

Fasting is an effective way to cut calorie intake, which partly explains these results. Timing matters, too. Our metabolism is programmed for daytime eating and nighttime sleep. Eating at night can throw off this balance, leading to weight gain and a greater risk of diabetes and heart disease.

In a study of 16 people reported in 2022 in Cell Metabolism, a final meal 2½ hours before bedtime increased hunger, reduced calorie burning and promoted the storage of body fat in participants, compared to when they took their last bites about 6½ hours before going to sleep.

Eating during a narrower time span is more in sync with the way the human body naturally operates, says neuroscientist Mark Mattson. An adjunct professor at the Johns Hopkins University School of Medicine, Mattson has been researching intermittent fasting for more than 25 years.

The idea, says Mattson, “particularly in people who are overweight, is to use intermittent fasting to change their eating pattern, which may help them keep their weight within healthier limits,” he says.

The most popular strategies for intermittent fasting are the 16:8 method, with fasting followed by a daily window of eight hours for meals, or the 5:2 weekly method, five days of eating normally and two nonconsecutive days of limiting food to 500 to 600 calories.

Many find the daily method easier to follow than the 5:2 plan, in which you’re “hardly eating anything two days a week,” says Mattson, who says he has been doing the daily plan himself since the 1980s.

Read more here from AARP to learn how to go about intermittent fasting safely, if you are interested in trying it, and talk to your doctor before trying a fasting plan.