New research indicates that restricting daily mealtimes to a nine-hour window and avoiding food for four hours before bedtime may help protect against cognitive decline in older individuals. These findings, presented at the American Society for Nutrition’s annual meeting, Nutrition 2026, in Maryland, suggest that when we eat is as important as what we consume.
The pilot study, led by Prof. Sue Shapses, a nutritional scientist at Rutgers University, involved 47 women aged 50 to 79 who were living with overweight or obesity. Over a six-month period, all participants were encouraged to reduce their daily intake by 500 calories. Within this group, 26 women were instructed to consume all their food within a specific nine-hour window, typically between 10am and 6pm. The remaining volunteers spread their meals over approximately 12 hours.
While both groups achieved similar weight loss, averaging about 7kg or 15lbs, those who utilized the restricted eating window demonstrated superior performance on tests measuring spatial planning and problem-solving. Researchers also observed indications of fewer errors in memory and learning assessments, although multitasking and reaction time results remained comparable between the two groups. Prof. Shapses described these effects as modest but significant enough to suggest that time-restricted eating could enhance the ability to manage everyday tasks and reduce errors related to attention and memory.
Dementia remains a critical global health concern, serving as the leading cause of death in the UK and the seventh worldwide, accounting for nearly 2 million deaths annually. While genetics and age are fixed risk factors, experts estimate that nearly half of all dementia cases could be delayed or prevented through lifestyle modifications. Obesity during middle age is linked to a 30% increased risk of later-life dementia.
Prof. Wendy Hall, head of nutritional sciences at King’s College London, noted that time-restricted eating is a plausible strategy for supporting brain health. She suggested that avoiding large meals late in the evening may improve blood sugar control, vascular function, and inflammation. However, Hall emphasized that these findings are preliminary and require further investigation through full, peer-reviewed studies to determine if the improvements are clinically meaningful.
Researchers now intend to further investigate the interaction between circadian rhythms, metabolism, and inflammation to understand the underlying mechanisms. Current trends in the UK and US often see people eating over a 14-hour period, leaving only 10 hours of overnight fasting. Previous research published in January has already associated finishing daily meals before 7pm with improvements in blood pressure, BMI, metabolic health markers, and waist circumference.
