Swap out the squeeze of lemon for a handful of ice: Cold drinks prompt your body to expend more energy to maintain its preferred 37-degree temperature. This means downing three 700ml servings of ice water in a day can help your body burn up to 100 extra calories, says Mitzi Dulan, nutritionist for the Kansas City Royals and author of The Pinterest Diet. Do it every day and you could lose up to 4.5 kg over the course of a year.
Not only is green tea gloriously calorie free, it can also help spur fat burn and weight loss. In one study, participants who drank four cups of green tea daily for two months lost 3kg more than those who drank just plain water, according to research published in the Journal of the American College of Nutrition. Another 2013 analysis from the European Journal of Nutrition found that regular green tea drinkers weigh less, have smaller waists, and reap these green tea health benefits. (Scientists speculate green tea's combo of catechin antioxidants and caffeine are behind the effect.) Choose fresh, hot brewed tea with nothing added—store-bought bottled brews tend to have fewer antioxidants and can be loaded with excess sugar. Stay away from unregulated green tea supplements, too: They're a frequent cause of liver damage and may contain unsafe doses of compounds isolated from tea.