Drinking green tea helped overweight and obese adults reduce their abdominal fat as they undertook an exercise program. The reason might be the action of the catechins which are the active ingredient of green tea and not found in black tea.

Summary

Green tea has long been promoted for its health benefits. Now a study shows that it can help reduce abdominal fat. Participants given green tea, which contains an active ingredient called catechin, lost more fat and a little more weight than those given black tea.

Introduction

Black and green tea come from the same tea plant but are processed differently, Green tea is taken and steamed straightaway after harvest, while black tea is left to mature. The result is that an enzyme converts an active ingredient called catechin into an inactive product when tea is matured. The catechin in green tea is said to help prevent cancer and people who drink a lot of green tea also seem to have a lower rate of heart attack and stroke. There is also interest in whether green tea can even help to 'burn off' fat - a subject which the current study addresses.

What was done

One hundred and seven overweight and obese participants were enrolled by researchers in the US and Japan. They did around three hours a day of moderate intensity exercise per week as part of a weight loss program. Half of the group received a green tea-like beverage with 625 milligrams catechin and 39 milligrams of caffeine. The rest drank a black tea-like beverage with just 39 milligrams of caffeine and no catechin.

What was found

After 12 weeks, the green tea drinkers had lost about two kilograms while the black tea drinkers lost half of that amount. Body fat composition was measured and the green tea drinkers were found to have lost significantly more abdominal fat. This kind of fat is a known health risk.

What this study means

Although the amount of weight lost in this study was small, over a period of time it could have significant health benefit in terms of reduced blood pressure and risk of heart disease and stroke. Green tea may be an acquired taste for some but you can get used to it by adding a little honey and brewing for only a minute or so. There are also mixes that have added ingredients like lemon, ginger and pomegranate.

Source

Green tea catechin consumption enhances exercise-induced abdominal fat loss in overweight and obese adults KC. Maki, MS. Reeves,  et al, Journal of Nutrition, February 2009, vol. 139, pp. 264--270