The granddaddy of weight-loss brews is green tea—it's filled with antioxidants called catechins, including a substance called epigallocatechin gallate (EGCG), which is believed to increase metabolism and help burn fat. "Researchers have found that green tea extract causes changes in the expression of fat metabolism genes, especially when it’s consumed consistently for longer periods of time," says Dr. Axe. One Chinese study found that when subjects drank tea that was super-rich in catechins twice a day, after 90 days they saw a decrease in belly fat, losing an average of 1.9 cm in waist circumference and 2.6 pounds of body weight, and another large review of studies concluded that green tea’s mix of EGCG and caffeine has a positive effect on weight loss and weight management.

Though green tea has long been thought of as the go-to variety for weight-loss, some researchers believe that oolong–a Chinese tea that falls somewhere between green and black—may be even more powerful. "Oolong tea promotes thermogenesis (so the body produces heat from energy, thereby burning more calories), and suppresses the production of new fat cells." says Dr. Axe. One small Japanese study found that for two hours after drinking oolong tea, women found their resting energy expenditure increase 10 percent, whereas the metabolism bump was only 4% after they drank green tea.

Black tea is actually made from the same plant as green tea—the difference is that the leaves are exposed to the air to trigger fermentation. One study found that over three months, those who drank three cups of black tea per day had less weight gain and reduced waist circumference compared with those who drank a caffeinated beverage that was devoid of the flavonoids in tea. Try any tasty black variety, such as English breakfast or Earl Grey.

Though some people swear sipping a cup of mint tea can stave off food cravings, there is little evidence behind the claim. One thing we know for sure, though? If you’re jonesing for a minty sip, a cup of unsweetened peppermint tea has far fewer calories than a sugary peppermint mocha.

Rooibos is an herb grown in South Africa that can be brewed into a delicious, caffeine-free cup of tea. Animal studies have suggested that rooibos tea may help with fat burning, though more research is needed to confirm the effect on humans. Either way, it makes for a colorful and tasty addition to your tea caddy.

White tea is one of the least-processed varieties—the leaves of the tea plant are picked before they're fully opened and then quickly dried, preventing them from oxidizing. This process gives the tea an exceptionally delicate flavor that is still packed with fat-busting polyphenols. "White tea is rich in antioxidants, boosts metabolism and helps to breakdown fat cells," says Dr. Axe.

Pu-erh is a black tea that comes from the Yunnan province of China; it's aged and fermented and can be purchased either pressed into cakes or as loose leaves. One study with overweight men suggested that drinking a daily cup of pu-erh tea can lead to a small weight loss.

Pu-erh is a black tea that comes from the Yunnan province of China; it's aged and fermented and can be purchased either pressed into cakes or as loose leaves. One study with overweight men suggested that drinking a daily cup of pu-erh tea can lead to a small weight loss.