Eating a single high-fat meal can cause a spike in blood pressure, researchers in Calgary say, a finding that suggests another way fat consumption may lead to heart damage. 

For the study published in the April issue of the Journal of Nutrition, researchers compared the effects of a high-fat breakfast with those of a low-fat breakfast in 30 university students aged 18 to 25 who were in good health.

Both meals contained about 825 calories. Among students who ate the fast-food eggs, sausage and hash browns, blood pressure measurements were up to 1.5 times higher than among those who breakfasted on cereal with skim milk, cereal bars, non-fat yogurt and an orange drink.

"Certainly we would expect to see this in people who eat high-fat meals on a regular basis," the study's senior author, psychology Prof. Tavis Campbell of the University of Calgary, told CBC News.

"However, we were surprised to see that we could measure this effect following a single meal in healthy, young individuals."

Studies show that a high-fat diet leads to artherosclerosis — a leading cause of heart disease, heart attacks and stroke — as well as high blood pressure. Prolonged cardiovascular response to stress is also linked to high blood pressure in the future, the researchers said.

"When we learn that even a single, high-fat meal can make you more reactive to stress, it's cause for concern because it suggests a new and damaging way that a high-fat diet affects cardiovascular function," Campbell said.

Stress tests

Participants fasted for 10 hours before eating. One week later, the experiment was repeated and they ate the opposite meal than before. Those eating the low-fat breakfast also took salt tablets, so the team could focus on the effects of fat rather than salt, which affects arteries.

Two hours after eating, the students were subjected to several standard laboratory stress tests such as holding an arm in ice water or speaking publicly about an emotionally provocative topic while their blood pressure and heart rates were measured.

"I maybe had some doubts at the outset of the study that a single high-fat meal would have any effect on physiological functioning," said Laura van Wielingen, a graduate student who co-authored the study. 

"So I'd say probably the main outcome of the study was quite surprising to me," adding the findings have changed the way she chooses what to eat.

More research is needed to understand how a high-fat diet affects blood vessel function, Campbell said. In the meantime, he said telling people never to eat something is a recipe for failure, but it is important to make informed choices.