Make the Most of Your Metabolism
From supermodels who douse their food with red pepper, to movie stars who swear by green tea, there's no shortage of claims for foods that are said to increase metabolism. But do any of them work?
"Actually, any food will increase your metabolism, mostly in the first hour after you eat -- that's when your system is most revved," says Kimball.
Further, she says, protein generally requires about 25% more energy to digest. So -- at least theoretically - a high-protein snack might rev metabolism a little more than a carb-heavy food with the same number of calories. That said, it's not clear that any food has special powers to boost metabolism significantly.
"Some studies have shown hot pepper and very spicy foods can increase metabolism by about 20% for about 30 minutes, but no one really knows if the extra burn lasts any longer than that, " says Kimball.
In a small study on Japanese women published in the British Journal of Nutrition, researchers found red pepper caused the body to heat up and revved the metabolism following a meal. But the most effects were seen primarily when the red pepper was eaten with high-fat foods (which are also higher in calories).
Another small study, published in the journal Medicine & Science in Sports & Exercise, reported that male athletes who added red pepper to high-carbohydrate meals boosted both their resting and active metabolic rates 30 minutes after the meal. But there was no evidence this burn power was lasting.
The same appears true for green tea, which contains a substance called EGCG (epigallocatechin gallate), a powerful antioxidant that some believe can bring about the same kind of calorie-burning effect as hot pepper.
In a study of 10 men published in the American Journal of Clinical Nutrition, researchers found that 90 milligrams of EGCG and 50 milligrams of caffeine taken with meals boosted 24-hour energy expenditure by 4% (caffeine alone did not show a similar effect).
But it's not clear whether this effect would be enough to boost weight loss. And that, says Radbill, is precisely the point.
"Essentially, you would have to drink so much of it in order to see even a small effect, that I don't think it's really worth it," says Radbill. "Drink green tea for other health-giving properties, but not to lose weight."
The bottom line, she says, is this: "All these foods may have a slight impact on metabolism, but the increase is still insignificant compared to what you need in order to lose weight."
Your best bet for keeping metabolism revved: Build muscles, snack on low-calorie, high-protein foods, and keep moving!