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If you’ve ever forgotten to defrost the chicken for dinner—and ended up ordering a pepperoni pizza instead—you know that healthy eating often requires planning.

And yet snacking is largely about spontaneity (as in, “It’s 3 p.m.—oh, jeez, I need some chips”). Having a game plan, however, can turn those grab-and-go moments into opportunities to eat well, conquer our worst urges, and pump up our energy, says Jim White, a registered dietitian in Virginia Beach, Va., and the owner of Jim White Fitness and Nutrition. These strategies and guidelines will help.

The New Snacking Rules
When to snack: Just because you always grab a granola bar and coffee at 10 a.m. doesn’t mean you should. Don’t snack because it’s part of your daily routine; do it when you’re a little bit hungry.

“I tell my clients to use a scale of 1 to 10, where 1 is starving and 10 is stuffed,” says Jessica Crandall, a registered dietitian in Denver and a spokesperson for the Academy of Nutrition and Dietetics. “You need a snack when you’re at a 3 or 4.” Many people won’t hit that mark until about three hours after a meal, but some will get there faster. In those cases, experts say, don’t punish your rumbling belly. Go ahead and have a bite. However, if you’re trying to drop a few pounds and are not truly hungry, consider holding out until lunch and having your first snack in the afternoon. A 2011 study conducted by the Fred Hutchinson Cancer Research Center, in Seattle, found that subjects who skipped midmorning snacks lost more weight than did those who had the snacks.
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What to snack on: Keep these general guidelines in mind when choosing a snack: 150 to 250 calories, about 3 grams of fiber, 5 grams of protein, and no more than 12 grams of fat. “Protein and fiber help you feel full and satisfied,” says Crandall. “So you shouldn’t feel the need to grab another snack soon after, and you’ll be less likely to overeat at your next meal.” Realistically, hitting all these markers with every snack is near impossible. So aim for overall balance. If one snack is short on protein, for instance, make sure your next one has a little extra. Find 19 healthy snack ideas.

How to snack: One word: mindfully. Treat each snack as a mini meal by taking one serving and, if possible, putting it on a plate, says Marissa Lippert, a registered dietitian in New York City and the founder of Nourish, a nutrition-counseling company. She recommends keeping a salad plate in your desk drawer at work. Why? We tend to associate a clean plate with satisfaction and a feeling of fullness (something an empty 100-calorie–pack wrapper may not supply).

Also, don’t multitask when you eat; simply enjoy the flavors of the food. Try to apply this strategy at regular meals, too. A 2009 study conducted at the University of Birmingham, in England, showed that when you’re distracted during mealtime (watching old episodes of Mad Men, say), you may be more likely to over-snack later on. “When we eat, we encode information about a meal, including the flavors, the textures, and how satisfied we feel, which is called a meal memory,” says Suzanne Higgs, a professor in the department of psychology at the University of Birmingham and one of the study authors. So Don Draper might be preventing us from forming proper meal memories, says Higgs. That can trick our brains, leading us to pick later, even though we may not be physiologically hungry.

3 Ways to Control Your Cravings
If, despite the best-laid (snack) plans, cupcakes still call your name, there may be something else going on—like stress or fatigue, says Lippert. These tactics may help you calm your emotions and stave off a junk-food binge.

Take a walk. Researchers at the University of Exeter, in England, found that a walk can help derail mindless snacking. In their study, published this year, subjects who took a brisk 15-minute walk before indulging in a chocolaty treat consumed less of it than did those who stayed put. “Stress, boredom, and fatigue are all factors that can cause us to snack when we’re not hungry,” says Hwajung Oh, a researcher in the department of sports and exercise at the University of Exeter and one of the study authors. Exercise may combat these, says Oh, thereby helping you avoid unnecessary nibbles.

Get more sleep. A lack of shut-eye has long been shown to be associated with overeating in general, but new research suggests that it can lead specifically to over-snacking. In a recent study conducted at the Center for Sleep Research, in Adelaide, Australia, people who slept for about four hours a night were more likely to eat excess snacks than were people who got more sleep. “Inadequate sleep can change the body’s levels of the hormones ghrelin and leptin, which regulate feelings of hunger and fullness, respectively,” says Crandall. Getting seven to nine hours of sleep may put those hormones back in balance.

Tweak your environment. If you’re tempted to snack at the same place or time every day (when you hit the couch after dinner, for example), some other cues could be to blame. According to a research review published in the journal Annual Review of Nutrition in 2004, lighting and temperature may affect how much you eat. Keep the thermostat at a warmer temperature (throw on a sweater if you can’t turn down the air-conditioning), since subjects in one study were found to eat more in cold temperatures. And switch on bright overhead lights. Research indicates that dim or soft lighting may prompt people to consume more food.

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