Your body may burn a few calories heating the cold water to your core temperature, says Madelyn Fernstrom, Ph.D., founder and director of the University of Pittsburgh Medical Center Weight Management Center. Though the extra calories you burn drinking a single glass doesn't amount to much, making it a habit can add up to pounds lost with essentially zero additional effort.

"Stay away from processed, high sugar, junk food, even fruit juice," says Michael Mountain, author of Ultimate Fat Loss Solution. Stick to protein, which increases metabolism by 30 percent for up to 12 hours, whereas carbs and fat increase metabolism by 4 percent for less than one hour. And don't forget fiber—it binds with metabolized fat and removes it from the body.
In one study published in the American Journal of Epidemiology, volunteers who got 22 to 55 percent of their total calories at breakfast gained only 1.7 pounds on average over four years. Those who ate zero to 11 percent of their calories in the morning gained nearly three pounds. In another study published in the same journal, volunteers who reported regularly skipping breakfast had 4.5 times the risk of obesity as those who took the time to eat.
In a study conducted by Swiss and German researchers, lucky participants ate about 1.5 ounces of dark chocolate daily for two weeks. Ultimately, these chocolate nibblers had lower stress-hormone levels and a more regulated metabolism than a control group. Scientists speculate that chemicals in cocoa, such as flavonoids, play a role in regulating metabolism by alleviating stress that can cause your fat-burning engines to go on the fritz. Should you think this is a license to go wild, take heed: We’re talking small amounts of high-quality dark chocolate. Researchers say 1.5 ounces is enough.
Ever wonder why your best friend can go through a pint of Ben & Jerry's without gaining a pound while just one spoonful goes straight to your hips? The answer lies in your metabolism, that little engine in your body that burns calories all day, every day. Because of genetics, some women burn fat faster than others. But age, weight, diet, and exercise habits also play a role.
Spreading your meals throughout the day might keep you from getting too hungry and overeating. If so, it is a good idea. Athletes perform better when they eat more often in smaller amounts. If you are someone who has a hard time stopping once you start eating, 3 meals a day may make it easier for you to stick to an appropriate intake than lots of little snacks.
You might want to think twice before ditching dairy if you’re trying to lose weight—despite what your Paleo-preaching CrossFit friends tell you. Cheese is a satisfying, portable, and inexpensive food that’s packed with calcium, vitamin D, and protein. “Calcium can also promote weight loss because it helps maintain muscle mass, which boosts and helps maintain metabolism, helping you burn calories more efficiently throughout the day,” says Tanya Zuckerbrot, RD, author of The Miracle Carb Diet: Make Calories & Fat Disappear—With Fiber! That doesn’t mean you can help yourself to a cheese-drenched casserole, though. Work cheese into fiber-rich snacks to make them more satiating.
Skimping on sleep can derail your metabolism. In a study at the University of Chicago, people who got four hours of sleep or less a night had more difficulty processing carbohydrates. "When you're exhausted, your body lacks the energy to do its normal day-to-day functions, which include burning calories, so your metabolism is automatically lowered," explains Peeke. 
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