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Restricting daily eating hours may offer brain benefits beyond weight loss, a new study suggests. Image credit: Giselleflissak/Getty Images
  • A new study suggests that older females who limited their daily eating window to 8 to 9 hours showed significant improvements in some aspects of cognitive function compared with those who ate over a typical 12-hour period.
  • While both study groups lost an average of 15 pounds over 6 months, only the time-restricted eating group experienced measurable cognitive improvements, suggesting the eating pattern itself may offer additional brain health benefits.
  • Participants following time-restricted eating made fewer errors on memory and learning tests, although these improvements did not reach statistical significance. No differences were seen in multitasking or reaction time.
  • However, the findings are from a small preliminary study, and the researchers plan to investigate the biological mechanisms behind the observed benefits and confirm the results in larger, more diverse populations.

Recent research from the World Health Organization (WHO) suggest that almost half of dementia cases globally could be delayed or even prevented.

Certain lifestyle choices, such as weight management and dietary choices, could potentially help lower the risk for dementia.

Time-restricted eating is a dietary approach where all daily food and calorie-containing drinks are consumed within a set time window each day, followed by a longer fasting period.

Previous research suggests that time-restricted eating may have a positive impact on cognitive function and mental health in older adults.

Although existing research has linked dietary and lifestyle habits with dementia risk, relatively few studies have explored whether changing eating patterns can directly influence cognitive health.

Now, a small clinical trial has found that limiting food intake to an 8 to 9-hour daily eating window may provide cognitive benefits for older women with overweight or obesity, beyond those achieved through weight loss alone. However, larger studies are necessary to confirm the results.

The findings come from a pilot clinical trial led by researchers at Rutgers University, presented at NUTRITION 2026, the annual meeting of the American Society for Nutrition. The study has not yet undergone peer review.

The small trial enrolled 47 females aged 50 to 79 years who had overweight or obesity. All participants received counselling to reduce their daily calorie intake by approximately 500 calories.

Participants were then assigned to either a time-restricted eating or a standard eating group.

Those in the time-restricted eating group limited food intake to fewer than 9 hours per day, typically eating between 10:00 a.m. and 6:00 p.m., with an average eating window of 8.2 hours.

The standard eating group continued eating across a more typical 12-hour window, averaging 12.6 hours per day.

After 6 months, both groups lost a similar amount of weight, roughly 15 pounds (lb) or 6.8 kilograms (kg) on average. However, differences emerged when the researchers assessed cognitive performance.

Compared with those following the standard eating schedule, participants in the time-restricted eating group demonstrated significant improvements in spatial planning and problem-solving.

Researchers also observed a trend toward fewer errors on tests measuring memory and learning, although these differences did not reach statistical significance.

No meaningful differences were found between the groups in tests assessing multitasking ability or reaction time.

“The main takeaway is that when people eat may matter for cognitive health, not just how much they eat,” Dung Trinh, MD, Internist MemorialCare Medical Group and Chief Medical Officer of Healthy Brain Clinic in Irvine, CA, who was not involved in the study, told Medical News Today.

“In this study, women who combined calorie restriction with an 8- to 9-hour eating window showed greater improvement in spatial planning and problem-solving than women who followed calorie restriction alone,” Trinh explained.

“At the same time,” he cautioned, “this was a small, 6-month study, so the findings should be viewed as preliminary. We are not saying that time-restricted eating prevents dementia or treats Alzheimer’s disease. Rather, the results suggest that meal timing may be an important and modifiable lifestyle factor that deserves further study.”

“For healthcare professionals, the findings highlight the potential value of looking beyond calories and weight loss alone and considering the timing and consistency of food intake as part of a broader discussion about metabolic and cognitive health,” he suggested.

The researchers suggest that restricting eating to an 8 to 9-hour window may provide modest cognitive benefits that extend beyond those of weight loss alone. They propose that reducing the eating window may lead to improvements in spatial planning, problem-solving, and reducing errors related to memory and learning.

Global cases of Alzheimer’s disease and other forms of dementia are increasing due to aging populations, with age being the strongest known risk factor for dementia.

Research also highlights that obesity and abdominal fat increase the risk of cognitive decline and dementia, with studies highlighting abdominal obesity as a significant, independent risk factor for early-onset dementia in females.

“The results suggest that meal timing may have contributed benefits beyond weight loss, because both groups lost a similar amount of weight, but the group following time-restricted eating showed greater improvement in planning and problem-solving,” Trinh noted.

“However, we cannot yet say that timing matters more than weight loss,” he cautioned. “Weight loss itself can improve metabolic health and may support cognition.”

According to Trinh:

“The more likely explanation is that these factors work together. Shortening the eating window may improve the alignment between food intake and the body’s internal clock, reduce late-day eating, and create longer daily fasting periods, while weight loss may improve insulin sensitivity and other cardiometabolic risk factors.”

“An important next step is to determine whether the benefit comes primarily from eating within a shorter window, eating earlier in the day, fasting longer overnight, or some combination of these factors,” he added.

Interventions that may help preserve cognitive function form an important area of research. While the current study was not designed to explain why the benefits occurred, the researchers believe several biological mechanisms could be involved.

They suggest that time-restricted eating may influence cognitive health through interactions between circadian rhythms, nutrient-sensing pathways, inflammation, and metabolic health. However, they note that further research is necessary.

Previous research has highlighted the possible role of chrononutrition, which describes the timing, frequency, and regularity of food intake in relation to circadian rhythm.

Aligning food intake with the circadian rhythm may support weight regulation and metabolic health, which, in turn, could influence brain health.

However, more evidence is necessary to establish whether these mechanisms explain the improvements seen in this study.

“Circadian alignment is especially promising because meal timing is one of the strongest signals the body uses to coordinate metabolism across the day,” Trinh highlighted. “Eating over a shorter and potentially earlier window may help synchronize glucose regulation, hormone release, sleep-wake patterns, and brain function.”

“That said, circadian biology, inflammation and metabolic health are closely connected. Poor circadian alignment can impair insulin sensitivity and promote inflammatory signaling, while improved metabolic health may support blood flow and energy use in the brain,” he explained.

“The most informative future studies will measure all three pathways together. This could include continuous glucose monitoring, inflammatory biomarkers, sleep and activity tracking, hormone rhythms and, eventually, brain imaging or Alzheimer’s-related biomarkers,” Trinh noted.

Although the results are encouraging, the researchers caution that the findings should be interpreted carefully.

The study involved a relatively small number of participants and only included females with overweight or obesity. Thus, it is unclear whether the findings would apply to males, younger adults, or people with different body weights or health conditions.

Additionally, the results have not yet undergone peer review or been published in a medical journal, so they should be considered preliminary and may change following peer review.

Larger, longer-term clinical trials will be necessary to determine whether time-restricted eating can meaningfully reduce the risk of dementia or help slow age-related cognitive decline.

“For many people, an 8- to 9-hour window may be achievable, but feasibility will vary considerably,” Trinh told us. “Work schedules, family meals, medications, social commitments, and cultural eating patterns can all affect adherence.”

However, he added that:

“One encouraging feature of this study is that participants selected their own eating window rather than being assigned an identical schedule. That flexibility may make the approach more practical. For some people, the most manageable change may simply be reducing late-evening eating and creating a more consistent overnight fasting period.”

“It is also important to recognize that time-restricted eating will not be appropriate for everyone. Older adults who are frail, losing weight unintentionally or struggling to consume enough protein and calories may need a different approach,” Trinh advised.

“I would recommend starting gradually rather than immediately attempting a very short eating window,” said Trinh. “A person who currently eats over 12 or 13 hours might first reduce that to 10 or 11 hours and then assess how they feel.”

“It may be helpful to choose a consistent window that fits daily life and, when practical, avoid concentrating food intake late at night,” he advised. “Nutritional quality remains essential. Time-restricted eating should not mean skipping nutritious meals or reducing protein, fruits, vegetables, fiber or overall nutrient intake.”

“People should also pay attention to energy levels, sleep, hunger, and their ability to meet nutritional needs,” Trinh added.

He cautioned that “anyone taking glucose-lowering medication, or anyone with diabetes, a history of an eating disorder, pregnancy, frailty or unintended weight loss, should speak with a healthcare professional before trying this approach.”

“Most importantly, time-restricted eating should be viewed as one possible tool within a broader healthy lifestyle, not as a substitute for balanced nutrition, physical activity, adequate sleep, or medical care,” concluded Trinh.