To see how stress might affect dietary fat, Kiecolt-Glaser and her colleagues recruited 58 healthy women to eat two separate but nearly identical breakfasts on two different days in their clinic. Their average age was 53 years.
Both breakfasts consisted of biscuits and gravy, and each contained 930 calories and 60 grams of fat, almost identical to the composition of a Big Mac and medium fries or a Burger King Double Whopper with cheese, the study authors said.
YOU MAY ALSO LIKE: Eat More Fiber, Lose More Weight
“They were modeled after fast-food meals,” Kiecolt-Glaser said.
There was one important difference. One breakfast was made mostly with saturated fat, while the other primarily contained a monounsaturated sunflower oil, the study said.
The women also completed a standardized interview about events that had stressed them out the previous day. “It’s an interview that separates out minor frustrations from events that are more meaningful and more likely to produce physiological changes related to stress,” Kiecolt-Glaser said.
Women free from stress tended to have better blood test results after they ate the monounsaturated fat biscuits and gravy, compared with when they ate the saturated fat-laden alternative, the research showed.
These women had lower levels of inflammatory markers, and they also tested lower for cell adhesion molecules — a substance that increases the likelihood of plaques forming on blood vessel walls, causing hardening of the arteries, the study reported.
But when women in the study had a stressful event before the breakfast test, the hardships of the previous day appeared to erase any benefits linked to the healthy fat choice.
“If they were stressed, it wiped out all the good stuff,” Kiecolt-Glaser said.
Even though the study focused on women, Kiecolt-Glaser said there’s no reason to think men would react differently to stress.
These findings jibe with others regarding the link between stress and diet, said Penny Kris-Etherton, a distinguished professor of nutrition at Penn State College of Health and Human Development.
“There is a growing literature that stress blunts good diet responses,” Kris-Etherton said.
It could be that a bad reaction to stress overwhelms the potential benefits of a healthy meal, or it could be that the stress itself alters the body’s processing of the meal, she said.
Interestingly, Kiecolt-Glaser and her colleagues found that stress did not make the body’s response to a high-saturated fat breakfast even worse, as they had anticipated.
“We expected we might see even greater adverse responses to the saturated fat meal, but we may have already maxed out,” she said. “It may be when you overload the system that much, you may have a hard time seeing the real effects of stress.”
In short, people who follow a heart-healthy diet also need to manage their stress, Kiecolt-Glaser and Kris-Etherton said.
That could mean sharing your problems with a friend or family member, exercising regularly, getting lots of good sleep, trying meditation or yoga, or simply doing something pleasurable like taking a warm bath or lighting a scented candle, they suggested.
This doesn’t mean that you get a free pass to eat an unhealthy meal following a rotten day, however, another expert noted.
“As a registered dietitian, this study would not change my recommendations in regards to a healthy diet or one rich in monounsaturated fat compared to saturated fats,” said Jennifer Kartashevsky. She is a certified diabetes educator with the Diabetes Alliance Program at the Mount Sinai Health System in New York City.
“We do know that both stress and diet can have an effect on inflammation in our bodies,” Kartashevsky continued. “The take away is to continuing to follow a diet rich in non-starchy vegetables, lean proteins, fresh fruits, whole grains and monounsaturated [fats] to give yourself a better base if stress does come your way.”
The research was published Sept. 20 in the journal Molecular Psychiatry.
For more on a healthy diet, visit the American Heart Association.