A Canadian university study proves that eating just one high fat meal can cause a spike in blood pressure. Researchers at the University of Calgary recently recruited 30 healthy undergraduate students to test their theory about the relationship between foods that are high in saturated fat and the body’s physical reaction during stress. The study was published in the Journal of Nutrition.

The students all fasted the night before the test. The next morning they were given two separate breakfasts with equal numbers of calories but vastly different fat contents. Half the group received a McDonald’s breakfast that consisted of an Egg McMuffin, Sausage McMuffin and two hash brown patties, which contained 42 grams of fat. The second half of the group was given a bowl of Kellogg’s Frosted Flakes with skim milk, a Kellogg’s Fruit Loops cereal bar, a Source fat-free yogurt cup and Sunny Delight orange juice. This meal contained just one gram of fat.

Two hours later the students were subjected to a series of stress tests, including a math test and a public speaking assignment. They also had blood pressure cuff wrapped around one arm that caused slight pain and had to stick one arm into freezing cold water. Individuals who had eaten the high-fat breakfast experienced a 25 percent increase in blood pressure compared to those who had eaten the low-fat meal. They also experienced an increase in heart rate and resistance of blood vessels. This cardiovascular reactivity can lead to the development of hypertension, which is a major risk factor for cardiovascular disease. Two weeks later the groups reversed roles, but the results remained the same.

Researchers believe that this study may shed some light on why so many young people are experiencing high blood pressure, particularly considering that just one high-fat meal had such an impact on healthy individuals. This study may also provide evidence that the average American diet, high in fast food, may be a major contributor to the increasing rate of heart disease.