Plans for working out and eating well often go awry, and the reasons for those lapses are not always obvious. Three new papers highlight unconscious influences that affect our choices.

Watch Out for Uncertainty

A job search or medical testing can breed doubts about the future, which in turn can interfere with our food choices. In one recent paper, being made to feel uncertain led people to select brownies over fruit. “Uncertainty appears to affect people by sapping the same kind of attention resources required to exert self-control,” says Katherine L. Milkman of the University of Pennsylvania and an author of the study in Organizational Behavior and Human Decision Processes. To counteract this effect, be mindful of situations that cause uncertainty and be aware that uncertainty can feel like fear, worry or anxiety. Accepting a lack of insight into the future as a part of life can help you spend less energy thinking about it, saving up self-control for decision making.

Think of Your Mind and Body as One

In several related studies published last fall in Psychological Science, researchers at the University of Cologne in Germany investigated the link between health behaviors and the belief in mind-body dualism—the concept that mind and body are two separate entities. Participants who were primed to embrace dualism made less healthy choices than participants encouraged to think of the mind and body as interrelated. The link goes both ways: when participants were primed with health-related concepts, they were less likely to subscribe to dualism. Study author Matthias Forstmann says people with a dualistic view may be more likely to neglect the body's health because they see the body as “a mere vessel for the mind.” This view is contradicted by research showing that thoughts can influence physiological markers such as heart rate and hormones [see “Healing the Body with the Mind,” on page 10] and that exercise has a significant effect on mood and cognitive abilities.

Beware Weak Temptations

It is easy to overestimate the healthiness of foods you find less tempting than your top vices, a paper in Appetite finds. Subjects judged the healthiness of different foods without realizing their nutritional profiles were identical. They were more likely to judge the less tasty and less attractive foods as healthier, and they also indicated they were more likely to consume those foods. Researchers say less desirable foods may not trigger our self-regulatory defenses the way our favorites do. If chocolate is your vice, don't underestimate that cookie just because you like it less. Look up nutritional information or just go ahead and have a reasonable portion of what you really want.