Restricted eating hours may reduce cognitive decline in older age
A pilot study suggests that eating within a nine-hour window and avoiding food for four hours before bed may help preserve mental skills in older women with overweight or obesity.
Researchers have found that confining meals and snacks to a nine-hour window and fasting for four hours before bedtime may help stave off cognitive decline in older age. A pilot study of 47 women aged 50 to 79 with overweight or obesity encouraged participants to cut 500 calories from their daily diet for six months. Within the group, 26 women were advised to eat only within a nine-hour window, typically between 10am and 6pm, while the rest spread their meals over about 12 hours.
At the end of the trial, both groups had similar weight loss averaging about 7kg. However, cognitive tests showed that those who confined their eating to the narrow window performed better on spatial planning and problem-solving tasks. There were also hints of fewer errors on memory and learning tests, though multitasking and reaction time tests showed no difference.
Prof Sue Shapses from Rutgers University noted that weight loss alone can slow cognitive decline, but there may be additional benefits from eating within an eight- to nine-hour window and stopping food intake four hours before sleep. The findings were presented at Nutrition 2026, the annual meeting of the American Society for Nutrition.
Dementia is the leading cause of death in the UK and seventh worldwide, causing nearly 2 million deaths annually. While some risk factors are unavoidable, experts believe nearly half of cases could be prevented or delayed through lifestyle changes. Obesity in midlife increases dementia risk by 30%.
Researchers now plan to investigate why meal timing matters, possibly involving circadian rhythms, metabolism, and inflammation. Prof Wendy Hall from King's College London, not involved in the study, said time-restricted eating is a plausible approach to support cognitive health in midlife and older adults with overweight, as it may improve blood sugar control, vascular function, and inflammation. She cautioned that the findings are preliminary and require peer-reviewed confirmation.
