A new study from the journal Molecular Psychiatry found evidence that daily stress can negate the effects of healthy eating. Does that mean that a frustrating morning commute or a difficult day at work really tricks the body into thinking that kale Caesar salad is a cheesesteak?
Well, not exactly. The double-blind study recruited 58 healthy women to test the impact of daily stressors on inflammatory responses to high-fat meals. The experiment looked at two types of fat: saturated fats, like the ones found in meat and dairy, which can be pro-inflammatory and lead to tissue damage in vital organs; and oleic acid, a monounsaturated fat, found in olive and other vegetable oils and in poultry fat, which has the opposite effect, and can actually reduce internal inflammation.
To determine whether stress made the body react to monounsaturated fat as if it were saturated fat, the experiment required that each woman eat two almost identical meals of eggs, turkey sausage, and biscuits and gravy, on two separate occasions, over the span of one to four weeks. The only difference between the two meals was the ratio of saturated fat to monounsaturated oleic acid. The researchers used a standardized, in-person interview called the Daily Inventory of Stressful Events, to quantify the participant’s level of prior day stress, and also took blood samples before and after each meal to measure complicated indicators of inflammation such as C-reactive protein, serum amyloid A, and vascular cell adhesion molecule-1.
The results of the blood tests showed that the bodies of the unstressed women reacted differently to both meals, with indicators of inflammation rising after eating the meal higher in saturated fat (as was expected), but the blood tests of the “stressed” women showed that their bodies reacted similarly to both meals, suggesting that their high levels of stress negated the anti-inflammatory properties of the oleic acid. Although this study used only a small sample size, its findings demonstrate the possibility that stress can negatively impact a seemingly healthy diet.