In addition to making your meals taste more pungent, garlic has anti-diabetic, blood-pressure-lowering and cholesterol-lowering properties. Large doses of garlic or related vegetables, such as leeks and onions, may also help protect against gastric and colon cancer. More research is needed to solidly connect garlic and garlic supplements to the treatment of these conditions, however. Garlic has not been associated with increased metabolism in humans, and extra intake is unlikely to help you directly lose weight.
About Your Metabolism
Speeding up your metabolism means you burn more calories all day long, making weight loss easier. Your body's metabolism consists of three basic parts. First is your basal metabolism, referring to the calories you use to perform basic functions, such as pumping blood and operating internal organs. Second is the calories you burn during activity, such as washing the dishes, showering or jogging. And third is the thermic effect of food -- calories you burn during digestion to break down and deliver nutrients throughout your body.
Garlic is sometimes touted as having a high thermic effect -- meaning it takes more calories to burn than other foods. Evidence of this is lacking. Even if garlic did have a high thermic effect -- this aspect of metabolism makes up, at most, 10 percent of your daily calorie burn, and an increase from a food you eat in such small quantities wouldn't be substantial.
Garlic's Nutritional Value
Garlic can't notably change your metabolism, but it does offer nutritional benefits. An ounce of garlic, which is almost 10 cloves, provides 23 percent of the daily value for manganese, 17 percent for vitamin B-6, 15 percent for vitamin C and 6 percent for selenium. Garlic also has almost 1 gram of fiber per ounce. Other nutrients, including copper, calcium, potassium and iron, are present in garlic, too.
Antioxidant Benefits of Garlic
A sulfur compound called allicin gives garlic its flavor and odor and has powerful antioxidant properties. Antioxidants fight free radicals, compounds that can cause disease and aging. Allicin in garlic is particularly powerful in fighting inflammation, which explains its seemingly positive effects in terms of diabetes, blood pressure, cholesterol and cancer. You'll get the most allicin from garlic when it releases allicin upon being chopped or crushed. The compounds take several minutes to form, however. So, prep your garlic and then let it sit 10 to 15 minutes before heating. Allicin doesn't have a known effect on your metabolism, however.
Boosting the Flavor of Food
Garlic may help your diet most by being a powerful flavoring agent with minimal calories. Use it roasted, spread on bread, in lieu of butter or mixed into roasted vegetables. With just 4 calories per clove, compared to 100 calories in a tablespoon of butter, it can help you save notable calories. Make a marinade for chicken with chopped garlic, lemon juice and a splash of olive oil. This option has more healthy fats and antioxidant properties than a tablespoon of barbecue sauce, which boasts 1 1/2 teaspoons of sugar and few nutrients.