The next time you have a deadline or need to concentrate, skip the drive-thru fast food restaurant. Foods high in saturated fats associated with fast food restaurants – like hamburgers and fries – are not only linked to health problems like heart disease and high cholesterol, but they may also tank your concentration and focus.

Researchers at The Ohio State University compared test results from 51 women who ate meals high in saturated fat with 930 calories and 60 grams of fat (designed to mimic the contents of various fast foods, such as a Double Whopper with cheese or a Big Mac and medium fries). They found that participants performed worse after eating a meal high in saturated fat (turkey sausage, biscuits, eggs and gravy with added palmitate-based oils high in saturated fat) compared to the same meal made with sunflower oil, which is lower in saturated fat. The results illustrate the link between diet and cognitive health, said study co-author Annelise Madison, a doctoral student at The Ohio State University.

The data examined the effect on attention up to five hours after eating a meal high in saturated fat, but Madison said the effect may take effect more quickly and have a longer-lasting effect – and may be more pronounced when comparing a high-fat meal to a low-fat meal.

“There have been a number of longer-term dietary studies that have found associations between diet and outcomes related to dementia and cognitive decline over time, and we’re interested in finding out if the effects are seen after a meal,” says Madison.

In high-fat diets, it seems that the type of fat you consume matters, she adds. While heart-healthy fats like omega-3s have been linked to brain health, your body may have a different metabolic and inflammatory response to a meal high in saturated fat.

The study is part of a growing body of research linking high-fat diets to impaired attention and an increased risk of poor decision-making and cognitive decline. Similarly, the study shows that those with high levels of trans fats in their blood may be up to 75 percent more likely to develop Alzheimer’s disease.

Dr. Nicolas Cherbuin, a professor at the Australian National University, believes that eating meals high in fat is accelerating the decline in brain health. His research has found that diets high in saturated fat are associated with neurodegeneration, or the loss and function of neurons, leading to a higher risk of brain health and cognitive decline, and a higher risk of developing dementia later in life.
“Our study shows that within the normal range, those with higher blood sugar have more neurodegeneration, and their brains shrink more than those with lower [blood sugar] levels,” explains Cherbuin.” When we’re young, we don’t see these differences…. But as the damage builds up, the repair mechanisms stop working quite well and cause the brain to age.”

Eating meals high in saturated fat seems to increase inflammation and trigger oxidative stress, a process that causes cellular molecules to damage cell walls and DNA, impair attention and focus, and create progressive problems in the brain.

“If a person eats highly processed junk food, some of the effects on the brain can happen very quickly,” says Cherbuin.” If people reduce their exposure to risk, they have better cognitive outcomes.”

Diets high in saturated fats should be avoided until activities that require focus and concentration, but long-term effects are also important.” You might think, ‘I’ll deal with my diet tomorrow,’ especially during COVID-19, and you might turn to some [unhealthy] foods to deal with everything,” says Madison.” If you really want to have full cognitive capacity and work on all cylinders, it’s important to even consider the short-term effects of what you’re consuming.” Aim for a balanced diet that combines complex carbohydrates, healthy fats, and high-quality protein.