Restricted eating hours may reduce cognitive decline

Researchers found early evidence that time-restricted eating might offer cognitive benefits for older women who are overweight or obese.

The pilot study, led by Professor Sue Shapses, a nutritional scientist at Rutgers University, compared women who ate within a nine-hour window to those who ate over a longer period.

Though weight loss alone can slow cognitive decline, Prof Shapses believes the timing of meals may offer additional protection.

Shapses said there may be “additional benefits” for people who do not eat outside an eight- to nine-hour window, and stop eating four hours before going to sleep.

What did the study show?

All participants in the study cut 500 calories from their daily intake over six months.

Of the 47 women aged 50 to 79, 26 ate only within a nine-hour window—typically between 10am and 6pm—while the rest ate within a 12-hour window.

Both groups lost an average of 7kg (15lbs), but the time-restricted group performed better on tests of spatial planning and problem-solving.

They also showed signs of making fewer errors on memory and learning tasks.

Professor Shapses described the effects as “modest” and said they suggested time-restricted eating may improve people’s ability to remember information for everyday tasks and reduce mistakes linked to memory, attention and problem solving.

The findings were presented at Nutrition 2026, the annual meeting of the American Society for Nutrition in Maryland.

The research team now hopes to explore why meal timing might influence cognitive health, considering factors like circadian rhythms, metabolism, and inflammation.

In many Western countries, including the UK and US, people often eat over a 14-hour period each day, leaving just 10 hours overnight without food.

However, research suggests that extending overnight fasting can offer health benefits.

A review published in January found that eating before 7pm was linked to improvements in body weight, BMI, waist circumference, blood pressure, and metabolic markers.

Professor Wendy Hall, head of nutritional sciences at King’s College London, who was not involved in the new study, said: “Time-restricted eating is a plausible approach to supporting cognitive health in midlife and older adults with overweight, not only because it may help with weight management but also because avoiding large meals late in the evening may improve blood sugar control, vascular function and inflammation.”

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She added that the findings are preliminary and that full peer-reviewed data would be needed to assess the clinical significance of the improvements reported.

Dementia remains the leading cause of death in the UK and the seventh leading cause worldwide, accounting for nearly two million deaths each year.

While age and genetics are unavoidable risk factors, experts believe that nearly half of dementia cases could be prevented or delayed through changes to lifestyle.

Obesity in middle age increases the risk of dementia in later life by 30%.