Actress Jennifer Aniston, 51, is known for her disciplined exercise regimen and a diet filled with nutrient-dense foods. She has often touted green tea as one of her go-to favorites to help maintain her seemingly boundless energy and slim, strong physique.

And she's not the only one.

A metastudy of 26 randomized, controlled trials involving 1,344 people found that folks who regularly consume green tea extract had a lower body weight and body mass index.

The results, published in Phytotherapy Research, showed that taking in less than 500 mg of extract a day for 12 weeks produced the greatest weight loss. (Studies use green tea extract instead of the liquid for easier dosing control.)

But that's not all green tea can do for you.

Other studies suggest that even one cup a day can reduce your risk of stroke and heart disease. Several have reported that green tea lowers your level of bad LDL cholesterol and reduces your risk for cardiovascular disease, diabetes, and some cancers. 

How does it work this magic? A serving of green tea contains 25-86 mg of epigallocatechin gallate (ECG), a phytonutrient that protects the body from the effects of toxins and inflammatory, artery- and organ-damaging free radicals.

Our advice: Stick with fresh-brewed green tea, not extracts (they're unregulated). Aim for one to four cups daily, with no sugar added.

Wondering about green tea's caffeine content? An 8-ounce cup delivers around 30-50 mg; a cup of coffee contains 70-140 mg.