The straight-up truth. As for other much-hyped metabolism boosters like green tea, caffeine, and hot peppers, it seems you’re better off focusing your weight loss efforts elsewhere. A compound in green tea called ECGC has been shown to elevate metabolism by a small amount, Clark tells WebMD, but it’s not enough to make a difference in weight. Capsaicin, the chemical in hot peppers that gives them their heat, boosts metabolism, too, but again, it’s not a significant enough change to have a weight loss benefit. Caffeine may or may not aid in weight loss -- as a central nervous system stimulant, it absolutely does increase metabolism, she says, but studies on its weight effects have had mixed results.
Go fish. EPA and DHA, the omega-3 fatty acids found only in fish oil, may have the power to dramatically boost your metabolism -- by about 400 calories per day, researchers from the University of Western Ontario report. Fish oil increases levels of fat-burning enzymes and decreases levels of fat-storage enzymes in your body. For the best metabolism boosting benefit, choose capsules containing at least 300 milligrams of EPA and DHA total.
Keep your cool. According to DavidAllison, PhD, professor of biostatistics and director of the clinical nutrition center at the University of Alabama, in Birmingham, our reliance on modern appliances like cozy heaters and chilly air conditioners may play a part in the size of our waists. Keeping ourselves too comfortable reduces the energy we expend to stay warm in the winter and cool in the summer, Allison says. Plus, both animals and people consume more food when temperatures are neutral, and eat less when they feel too hot or cold. You don't need to trash your modern conveniences, of course, but it won't hurt to turn them down a little -- especially if it means you'll burn calories without lifting a finger.
Let’s get physical. Never sit when you can stand, or stand still when you can walk. Thanks to desk jobs, family commitments, and a great lineup of must-see TV shows, most of us move less at ages 30, 40, and beyond than we did during our teens and twenties, Berardi says. Regular periods of movement -- whether it’s a trip to the office water cooler or a stroll around the block after lunch -- nudges a sluggish metabolism into gear, lifting your spirits and obliterating excess fat.
SOURCES: John Berardi, PhD, CSCS, president, Precision Nutrition; author, The Metabolism Advantage. Berardi, J. The Metabolism Advantage, Rodale Press, 2006. Sanjay Patel, MD, assistant professor of medicine, Case Western Reserve University, Cleveland, Ohio. DavidAllison, PhD, professor of biostatistics and director of the clinical nutrition center at the University of Alabama, Birmingham, Ala.Noreen, E. Medicine & Science in Sports & Exercise, May 1, 2003; vol 35, supplement 1: p S248. Kristine Clark, PhD, RD, FACSM, assistant professor and director of sports nutrition at Pennsylvania State University.