Set an overarching goal and bring it to mind when your self-control slips.

Tempted to overindulge? Remind yourself why you want to stay healthy.

RODALE NEWS, EMMAUS, PA—So it’s 5 o’clock and time to go to the gym, but you’re tired and tell yourself you’ll work out tomorrow. Sound familiar? According to a new study published in the Journal of Consumer Research, if you simply remind yourself of the benefits of sticking to your exercise plan, you may have better luck talking yourself into putting on those running shoes.

THE DETAILS: Researchers put their volunteers through a series of challenging activities, like reading complex articles about health, playing word games, and doing writing assignments. In a subsequent test, they were then asked to floss their teeth, not knowing they were being monitored by the researchers to see how long they actually flossed. In another test, the subjects performed a second task while a tempting plate of cookies lay within reach, and the scientists observed how many cookies they couldn’t resist eating.

The researchers found that activities that make people feel tired or stressed-out can prevent them from engaging in healthier behaviors later on. Study participants who had been exhausted by reading a complex article about hepatitis were less inclined to floss at the end of the experiment. “If you’ve just read something that’s unpleasant and it’s stressing you out, you’re already feeling tired and when approaching another task, you think, ‘Oh, I want to skip this,” says lead author Nidhi Agrawal, Ph.D., assistant professor of marketing at Northwestern University’s Kellogg School of Management. “People are overruled by immediate feelings,” she explains. People who’d been mentally fatigued also tended to eat more cookies, showing how self-control can plunge when the going gets tough.

But here’s the good news: The study also suggests a way to fight back. In both scenarios, people who were able to find in the articles they read information that was beneficial to their long-term health were then able to overcome their feelings of stress and exhaustion. They were more likely to floss for longer periods of time or to eat fewer cookies. Keeping the long-term goal of better health in mind seems to help motivate people to make healthy choices even when their energy level is low and temptation is high.