Eating high-fat meals can leave you more prone to stress and its damaging effects on the heart, according to a new Canadian study.
In fact, a single fatty meal like eggs, sausages and hash browns can drive up blood pressure and damage blood vessels, even compared to a sugary meal of cereal, juice and yogurt, researchers found.
"You can see the impact with just one high-fat meal," said Tavis Campbell, a professor in the department of psychology at the University of Calgary.
"So you can imagine the long-term effects. ... There is going to be a lot of extra wear and tear on the body."
Dr. Campbell, a specialist in behavioural medicine and senior author of the study, said it is noteworthy that people often turn to high-fat meals such as fast foods when they are already stressed, so there is probably a compounding effect.
"When people are stressed, they pay very little attention to their diet, but what they eat can exacerbate their stress response," he said.
To conduct the research, published in today's edition of The Journal of Nutrition, scientists enlisted the help of 30 healthy university students aged 18 to 25.
After a 10-hour fast, the students were fed either a high-fat or a low-fat breakfast. One week later, the process was repeated, with each student receiving the meal they had not been fed previously.
The high-fat version was a McDonald's breakfast - Egg McMuffin, Sausage McMuffin and two hash brown patties - featuring a whopping 42 grams of fat. The low-fat breakfast consisted of a bowl of Frosted Flakes with skim milk, a Froot Loops bar, a fat-free yogurt and a Sunny Delight orange drink.
The meals each contained about 830 calories, and students eating the low-fat foods were given salt tablets to balance the salt content. (Excess salt intake drives up blood pressure, so researchers wanted to ensure it was the fat, not the salt, affecting blood vessels.)
After each session, the subjects underwent a series of standard laboratory stress tests such as holding an arm in ice water, speaking publicly about an emotionally provocative topic, doing a math test, and having a blood-pressure cuff inflated on their arm to the point where it was uncomfortable.
"Regardless of the task, when students consumed the high-fat meal, they showed greater reactivity in several cardiovascular measures, including blood pressure, heart rate and resistance of blood vessels," said Fabijana Jakulj, a graduate student who used the research as the basis for her honours thesis.
Beth Abramson, a Toronto cardiologist and spokeswoman for the Heart and Stroke Foundation of Canada, said the study adds important details to the body of knowledge about cardiovascular disease.
"This kind of study is mechanistic. It helps us understand the whys of what we see in clinical practice," Dr. Abramson said.
"In this case, the research lends credibility to the notion that we are what we eat."
She said the study is intriguing because it is among the first to examine the impact of fat consumption on blood-vessel function in healthy young people.
While the results of eating a single high-fat meal are probably transient, she said, the research "may help explain why, with a diet of repetitive intake of high-fat foods, we see a much higher risk of heart disease and stroke.
Cardiovascular disease is the leading cause of death in Canada, according to Statistics Canada. In 2003, the most recent year for which figures are available, 73,825 Canadians died of heart disease.
The high-fat/low-fat menus
Both meals contain roughly the same number of calories, but one has substantially more fat. Lead researcher Tavis Campbell said the low-fat meal isn't healthy either. But for the purpose of the study, the low-fat meal had to contain lots of sugar in order to bring its calorie count up to the level of the high-fat meal.
