A small clinical trial suggests that restricting daily meal intake to shorter periods of time may have cognitive benefits in older women that exceed those of weight loss alone.
This pilot study followed overweight or obese women participating in a six-month weight loss program. Participants who ate within a window of about 8 to 9 hours per day showed greater improvement on certain thinking tests than those who split their meals into about 12 hours.
“Simply losing weight can prevent some of the age-related decline in cognitive function. These data suggest that stopping eating four hours before bedtime and reducing food intake to eight to nine hours a day may have additional benefits, compared to the typical eating window of 12 hours a day,” said Sue Shaps, DFASN, professor at Rutgers University and principal investigator of the study, Rutgers RWJ Medical Center.
Shapses and colleagues presented their results at NUTRITION 2026, the annual flagship meeting of the American Academy of Nutrition, held July 25-28 in National Harbor, Maryland, outside Washington, DC.
Meal timing and dementia risk
As the population ages, Alzheimer’s disease and other dementias are becoming more common. Women and people who are overweight or obese also tend to be at higher risk of developing these conditions.
Researchers have long studied how diet and other lifestyle habits relate to dementia risk. However, relatively few trials have tested whether changing these behaviors can directly reduce that risk.
The new trial involved 47 women aged 50 to 79 who were overweight or obese. Each participant was instructed to reduce their daily calorie intake by 500 calories.
The 26 women were instructed to consume all their food within 9 hours each day. The remaining participants continued eating over a more typical 12-hour period each day.
Women in the time-restricted eating group generally ate between 10 a.m. and 6 p.m. Their average meal time was 8.2 hours per day, compared to 12.3 hours per day for women in the standard diet group.
Different cognitive outcomes for similar weight loss
After six months, the women lost an average of about 15 pounds. Weight loss was similar in both groups.
Despite these comparable results, women who ate within 8 to 9 hours performed significantly better on tests measuring spatial planning and problem solving than women who continued to eat for 12 hours.
The time-restricted group also tended to make fewer mistakes on tests involving memory and learning, but the difference did not reach statistical significance. The researchers found no significant differences between the groups on reaction time or multitasking tests.
“Time-restricted eating had a modest effect on improving spatial planning and problem-solving skills, and reducing errors associated with memory and learning,” Chapseth said. “These results suggest that the ability to remember information during daily tasks is improved and errors related to memory, attention, and problem solving are reduced. Shorter meal windows predicted greater improvements.”
Why is it effective to shorten meal times?
The researchers emphasized that the trial was small and that larger studies are needed to determine whether improvements in cognitive function can be seen in a broader population.
Future research will also investigate why meal timing affects the brain. Possible explanations include interactions between circadian rhythms, inflammation, metabolic health, and biological pathways that help the body sense and respond to nutrients.
The research team presented the study at the Aging and Chronic Disease (II) poster session held at the Gaylord National Resort and Convention Center on Sunday, July 26 (abstract).
The findings should be considered preliminary. Abstracts presented at NUTRITION 2026 were reviewed and selected by a panel of experts, but typically do not undergo the full peer review process required for publication in a scientific journal.
