Oil up

Tip the scales with a dose of fish. Researchers at Laboratoire de Biologie de la Nutrition in France found men who replaced six grams of fat in their diets with two grams of fish oil boosted their metabolisms and lost an average of two pounds in 12 weeks. Use it as mouthwash and lose unwanted friends, too.

Use the afterburn

Smashing out a session of intense exercise triggers afterburn: when your body cools off and repairs muscle micro-trauma. Afterburn alone, says Dr John Berardi, author of The Metabolism Advantage (Rodale), can dissolve 100 to 200 calories. More than carpet burn, according to our tests.

Max your protein

"Protein burns hotter than other food sources," says Dr Mark Hyman, author of Ultrametabolism (Scribner Book Company). In fact, protein-based calories will be torched roughly twice as quickly. Jump-start your metabolism early with two scrambled eggs for breakfast. Smokin'.

Sizzle snacks

Spicy food, spiky metabolism. A study from Université Laval in Quebec found that men who ate red pepper-packed snacks and meals, washed down with coffee, burnt nearly 1000 more calories a day than those eating cooler food. Go steady, mind, unless you want a fire-engine complexion.

C the light

Sitting around eating green peppers, tomatoes and other foods rich in vitamin C fans the flames of your fat-burning furnace. A University of Colorado study found that vitamin C can juice up your resting metabolism by almost 100 calories per day. Easier than weights, but unlikely to give you big arms.