Limiting daily eating to around eight hours and avoiding food for at least four hours before sleep may benefit not only weight loss but also cognitive function, according to a new study.
Britain's The Guardian recently reported the results of a time-restricted eating study conducted by researchers at Rutgers University in the United States. The study was presented at Nutrition 2026, the annual conference of the American Society for Nutrition.
A research team led by Sue Shapses, a professor in the Department of Nutritional Sciences at Rutgers University, examined the effects of time-restricted eating on cognitive ability over six months in 47 overweight or obese women aged 50 to 79. All participants were instructed to reduce their daily caloric intake by 500 calories from their usual amount. The researchers then divided the participants into two groups.
One group was allowed to eat only within a nine-hour window each day. In practice, participants ate for an average of about eight hours and 12 minutes, and most finished eating between 10 a.m. and 6 p.m. The other group had no time restriction. They ate for an average of about 12 hours and 18 minutes.
After six months, both groups lost an average of about 7 kilograms. Notably, differences emerged in cognitive function tests. The time-restricted eating group performed better than the comparison group on tests assessing spatial awareness, planning ability, and problem-solving skills.
The group also showed a tendency toward fewer errors in tests of memory and learning ability. However, no clear difference was found between the two groups in the ability to handle multiple tasks simultaneously or in reaction speed.
"Weight loss alone can help slow the cognitive decline that occurs with aging," Shapses said. "Eating within eight to nine hours and finishing meals at least four hours before sleep may provide additional benefits." She added, "It shows that time-restricted eating can help remember information in daily life and reduce errors related to memory or concentration."
The researchers suggested that circadian rhythms, metabolic changes, and inflammation regulation may be among the reasons reducing eating time affects brain function. Shapses also explained in her presentation materials that time-restricted eating extends fasting time, which can restore the body's biological clock and affect blood sugar control and metabolic health.
She added that eating large amounts of food late at night can affect blood sugar control and sleep quality, and that adequate sleep, which is also an important factor in maintaining brain health, may have played a role.
The study has limitations, however, including its small sample of 47 participants and its status as an early study confirming the link between time-restricted eating and improved cognitive function.
