A new study suggests that while adopting a healthier diet can improve brain function, it may not fully reverse cognitive damage caused by long term consumption of high sugar and high fat foods, highlighting the importance of maintaining healthy eating habits throughout life.

Researchers found that diets rich in sugar and unhealthy fats can negatively affect memory, learning, and overall cognitive performance. While switching to a healthier diet later in life showed some benefits, the study indicated that certain brain changes linked to prolonged unhealthy eating may persist even after dietary improvements. The findings were based on data obtained from animal models and add to growing evidence connecting nutrition with long term brain health.

Experts say the results reinforce concerns about the increasing consumption of ultra processed foods, sugary beverages, and high fat diets, which have become more common globally. Previous studies have linked poor dietary habits to obesity, diabetes, cardiovascular disease, inflammation, and a higher risk of neurodegenerative disorders such as Alzheimer’s disease.

According to the WHO, dementia affects more than 55 million people worldwide, with nearly 10 million new cases diagnosed each year. Alzheimer’s disease accounts for an estimated 60–70% of all dementia cases globally.
Researchers emphasized that brain health is influenced by lifestyle choices made across the lifespan. Along with a balanced diet, regular physical activity, quality sleep, stress management, smoking cessation, and mental stimulation have all been associated with healthier cognitive ageing.

Healthcare professionals often recommend dietary approaches such as the MIND diet, Mediterranean diet, and other nutrient-rich eating patterns that emphasize fruits, vegetables, whole grains, nuts, fish, and healthy fats. These diets have been associated with slower cognitive decline and reduced risk of age-related neurological disorders.

While further human studies are needed to confirm the findings, experts say the research serves as an important reminder that protecting brain health should begin early. Adopting healthy dietary habits before cognitive decline occurs may offer the greatest benefits in preserving memory, learning ability, and overall brain function later in life.