One high-fat meal can disrupt brain blood flow, finds study

A greasy takeaway may feel like a harmless Friday night treat, but new research suggests it could have immediate effects on brain health.

A study published in The Journal of Nutritional Physiology has found that eating just one high-fat meal can impair blood flow to the brain, potentially raising the risk of stroke and dementia over time.

Fat is an essential part of the diet, providing energy, transporting vitamins, and protecting organs. However, not all fats act the same way. Saturated fats commonly found in foods like pizza, fried snacks, and creamy desserts are already known to harm heart health. The new research shows their impact may extend to the brain as well.

The brain depends on a constant supply of oxygen and glucose, delivered through stable blood flow. This is normally regulated by a process called dynamic cerebral autoregulation, which acts like a ‘shock absorber to protect the brain during normal blood pressure fluctuations. When this system is impaired, however, the brain is exposed to harmful swings in blood supply, raising long-term risks of stroke and dementia.

To test the effects of a high-fat meal, researchers recruited 41 men, 20 aged 18-35 and 21 aged 60-80. Participants consumed a milkshake nicknamed ‘the brain bomb’, containing 1,362 calories and 130 grams of fat, equivalent to a fast-food takeaway.

Blood vessel health was measured before and four hours after the meal using ultrasound. Participants also performed body-weight squats to test how well their brains could maintain blood flow during changes in blood pressure.

The results showed that, in both younger and older men, blood vessels became less able to expand and regulate flow after the high-fat meal. The effect was stronger in older participants, with their brain’s protective response reduced by around 10%.

Researchers warn that while a single indulgence won’t cause immediate disease, repeated high-fat meals could weaken the brain’s defenses over time, leaving it more vulnerable to serious conditions like stroke and dementia.