Turning to chocolate or a candy bar during stress peaks might seem comforting, but unhealthy food choices can actually exacerbate stress. This is because of how it affects the blood flow to the brain, researchers found.

Comfort fatty food can stress the body

A team from the University of Birmingham gave a group of 21 young healthy adults and gave them two butter croissants for breakfast. The participants were asked to do mental maths faster and faster. They were told when they got an answer wrong. They could also see themselves on the screen while doing the exercise.

The experiment was designed to simulate everyday stress that we may deal with at work or at home, Rosalind Baynham, one of the study authors, said in a news release. “When we get stressed, different things happen in the body, our heart rate and blood pressure go up, our blood vessels dilate and blood flow to the brain increases,” Baynham said.

Eating fatty foods when mentally stressed reduced vascular function by 1.74%, the researchers found. Previous studies have shown that a 1% reduction in vascular function leads to a 13% increase in cardiovascular risk. “This impairment in vascular function persisted for even longer when our participants had eaten the croissants,” Baynham said.

The researchers observed reduced arterial elasticity in participants up to 90 minutes after the stressful event was over. Eating fatty food also reduced brain oxygenation in the pre-frontal cortex, with lower oxygen delivery during stress compared to when participants consumed a low-fat meal. Furthermore, fatty foods had a negative effect on mood.

“We all deal with stress all the time, but especially for those of us in high-stress jobs and at risk of cardiovascular disease, these findings should be taken seriously. This research can help us make decisions that reduce risks rather than make them worse,” Jet Veldhuijzen van Zanten, study author, said in a news release.

Eating healthier food

The researchers suggested that consuming a diet low in fat may mitigate the impact of stress on people’s recovery. Following the intake of a low-fat meal, vascular function still experienced a negative effect during stress. However, this decline returned to baseline levels 90 minutes after the peak of stress.

Further research also showed that by eating “healthier” foods, especially those rich in polyphenols (beneficial plant compounds with antioxidant properties), such as cocoa, berries, grapes, apples and other fruits and vegetables, this reduction in vascular function can be fully prevented.

“Food choices around stressful episodes can exacerbate or protect from the effects of stress on our cardiovascular system. The good news is that this means we can do something about this,” Catarina Rendeiro, study author, said in a news release. “Food choices around stressful episodes can exacerbate or protect from the effects of stress on our cardiovascular system.”

The studies were published in the journals Frontiers in Nutrition and Nutrients.