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The Best Time to Start a Diet

Elise Solé
Senior Writer
July 22, 2014

Photo: Donna Trope/Trunk Archive

Whether it’s vowing to join a spin class and never quite making it there or putting a cap on weekly wine consumption and sneaking nightly sips, it’s easy to fail at maintaining fitness and diet goals. But before beating yourself up for lacking restraint, know this: People posses a limited amount of willpower, according to a small study published in the Journal of Consumer Research. “We found that when people exert too much self-control, they’ll run out of it in the long term,” lead study author William Hedgcock, PhD, professor of marketing at the University of Iowa, tells Yahoo Heath. “So, for example, if you direct all your mental energy toward eating a healthy dinner, you’re more likely to eat dessert — later.”

Rather than putting all that internal pressure on yourself, then, why not refocus your efforts outward? Various studies show that environment plays a major role in our ability to resist temptation. So here are five times — moments, situations, days of the week — to take advantage of, all in the name of jumpstarting healthy habits.

Friday morning: Almost everyone drops a few pounds during the week and gains weight on weekends, with most people weighing their lowest on Friday morning when the results of their efforts accumulate on the scale, says recent research out of Cornell University. Chalk it up to the regimented nature of the workweek (which limits time for splurging) and the lazy allure of weekends, when people adopt carefree attitudes. Even if you never weigh yourself, knowing you’re slimmest on Friday might just be enough motivation to decline those happy hour margaritas.

Sunny days: Longer, brighter days and blue skies are a dieter’s best friend, says classic research conducted by the University of Georgia, which found that subjects eat 200 more calories per day starting in the fall and continuing through winter. The reason could be evolutionary — darker, shorter days may prompt us to overindulge due to subconscious fear of scarce resources in winter. Or, people may eat more in the colder months due to an abundance of nostalgic, holiday comfort food and less opportunities to exercise outside. And of course, there’s less pressure to look good in a swimsuit. Whatever the reason, use the summer months to take up an outside sport and eat lighter foods.

On the fourth day of your menstrual cycle (for women-only, natch): Coupled with bloat and mood swings, your impending period evokes salt, grease, and carb lust. But four days after its arrival, you’ll have a better handle on your hunger pangs, says Gabrielle Lichterman, author of “28 Days: What Your Cycle Reveals about Your Love Life, Moods and Potential.” “During the first half of your cycle, you experience a dip in progesterone, a hormone that revs fatty food cravings,” she tells Yahoo Health. “A rise in dopamine, a mood-boosting neurotransmitter, also helps you say no to second helpings.” 

When you’re exhausted: People actually make better decisions about their health when they’re tired, according to a two-part study published earlier this year in the Journal of Consumer Research. In one experiment, subjects completed a survey, either before or after they exercised, about their health routines. As compensation, they could select either a tube of sunblock or moisturizer; the post-exercise people more often chose the sunblock. In the second study, both tired and energetic subjects were asked to read pamphlets about kidney disease, then decide whether or not to be tested; those who felt depleted were the ones more likely to agree to the test. “When people are tired, they rely more on their survival instincts and allocate their remaining resources to protect their health,” study coauthor Angela Y. Lee, a professor of marketing at Northwestern University, tells Yahoo Health. That’s not to say you should decide to hit the gym when you’re really dragging. But opting for a light homemade meal over caloric takeout food after a long workday is more the right idea.

The day you join a gym: Starting both a diet and exercise routine on the same day may seem overwhelming, but new research from Stanford University says the most effective dieters tackle both goals at once. In fact, people who do so most often meet government guidelines for exercise — 150 minutes per week — and nutrition, consuming five to nine servings of fruit and vegetables daily. Still, if the idea of making two major changes at once seems unrealistic, start with exercise, often considered the most challenging feat.