No. 10: Take Your Vitamins
You try. You really do. But even on your best day, you're not certain you're getting all your essential nutrients. "Ninety-nine out of 100 Americans don't meet the minimum standards," Somer says. But even small vitamin and mineral deficiencies that you have today can lead to big-time health problems, such as osteoporosis, tomorrow. Worrying about what your body lacks is enough to make you want to exchange that spinach for a Snickers.

Secrets to success: Supplement with supplements, your nutritional insurance policy -- they've got you covered in case you don't get everything you need from food. "If you're female, you probably need calcium and vitamin D," Moore says. "If you're menstruating, you need a multivitamin with iron, and if you're vegetarian, you most definitely need iron." A multivitamin alone often won't cut it because "iron and calcium can't be given in the same pill; they bind to each other, decreasing absorption," Moore says.

How you take a supplement also matters. "You've got to have food in your stomach in order to absorb nutrients," Somer says. But it's not necessarily as easy as tossing back your pills right after breakfast, because the compounds in coffee and tea -- whether it's regular or decaf coffee, black or herbal tea -- will block iron absorption. Don't take a supplement when those are in your stomach," Somer says. Citrus and vitamin C, on the other hand, aid the absorption of vitamins, "so it always helps to take your multivitamin with a little orange or grapefruit juice," Moore says. The smartest suggestion: Line your vitamins up next to your toothbrush, and take them with a small glass of juice before brushing your teeth at bedtime. That way you'll have dinner in your stomach, but no coffee in your system.

No. 11: Stop Scarfing the Bread Basket
Downing a caddy of carbs -- or committing other impulsive acts of noshing -- leads to overeating, weight gain, and all the attendant health problems.

Secrets to success: It's better to eat a little now, when you first feel hungry, than a lot more later, when you're truly starving. "Snacking is the best way to maintain your blood sugar and weight," says nutritionist Keri Glassman, author of "The Snack Factor Diet" ($20, Crown). People think snacking is cheating or ruining your appetite, but I'm all for ruining appetite so you eat in a measured way all the time. Glassman finds that healthy noshing keeps her clients from bingeing on a huge dinner after skimping all day. "Following the appetite-ruining theory," Bloom says, "I always carry a baggie of almonds in my purse. I have a couple while walking to the restaurant for dinner, and it prevents me from dipping into the bread and butter."

The key to smart snacking, says Glassman, is choosing food that combines some protein, a few carbs, and a little fat, so your body digests it slowly, keeping your blood sugar fairly level. A nutrient-bankrupt pretzel, for example, is a quickly broken-down carb that will give you a sugar rush, followed by a dip that makes you sleepy (and, shortly afterward, hungry again). Instead, Glassman likes to spread Laughing Cow low-fat cheese on cucumber slices, eat a cup of edamame, or throw together a little snack mix of Wheat Chex, raw almonds, a few shards of dark chocolate, and sunflower seeds.

Along with skimping on snacks, imbibing booze can also lead to overeating by wearing down your resolve to pass on dessert. (By all means, get the tarte tatin if you have room for it. But if you've already eaten your own appetizer, half your friend's, and an entree, do you really want dessert, or is that the shiraz ordering?) If you do drink, think of it as a substitute for dessert; both tend to be filled with sugar and calories, so indulge in one or the other.

Keep in mind that while one glass a day of any kind of alcohol may help reduce your risk of heart disease, there is a direct link between how much you drink and your breast-cancer risk. "Alcohol increases the amount of estrogen our bodies produce, and estrogen is what really fuels breast cancer," Horner says. "One drink a day increases the risk by 11 percent, two drinks by 22 percent to 40 percent, three by 33 percent to 70 percent." If you're going to indulge, red wine has more healthy polyphenols than white, Somer says. Of course, blueberries and red grapes are also antioxidant-rich (not to mention lower in calories), so don't start overdrinking to your health.