Green tea seems to enhance the benefits of exercise.
Four scientists at the Human Performance Laboratory at the University of Birmingham in England gave green tea extract (3 capsules containing a total of 890 mg of green tea polyphenols and 365 mg of ECGC) or a placebo to healthy men 24 hours before they did workouts at maximum velocity on a stationary bike.
The men who took the green tea supplement showed:
- 17 per cent faster fat burning,
- approximately 17 per cent more fat burning, and
- improved sensitivity to insulin, helping muscles take up both glucose and amino acids to repair themselves and grow after exercise.
But that's taking green tea supplement and then getting out and exercising just as hard as you can for 30 minutes. What about green tea and moderate exercise or no exercise at all?
Green tea has lesser benefits for people who do not exercise.
A different group of scientists at a different institution investigated using a much smaller dosage of green tea catechins and ECGCs to stimulate fat burning at rest. Giving volunteers about 1/3 as much green tea extract as was used in the University of Birmingham study, scientists at the University of Geneva in Nice, France found that using green tea supplements resulted in:
- 4 per cent faster fat burning even at rest, with
- no loss of muscle mass
even when volunteers did not exercise. The French scientists found that antioxidants in green tea only stimulate weight loss if they are combined with caffeine at low doses. The English research team found that green tea supplements stimulate fat burning and weight loss even without caffeine if the polyphenols and ECGCs are given in a higher dose (about 900 and 300 mg a day, respectively). So, to restate:
A low-dose green tea diet aid needs to be combined with caffeine to help you lose weight. But a higher-dose green tea capsule or diet aid works even without caffeine.
There are over 250 other studies in the medical literature on the role of green tea in weight loss, and, as a former formulator of natural health products, I've read them all. But here's what you need to know about any green tea diet plan:
- If you're getting a low dose of green tea extract (less than 890 mg of green tea catechins/polyphenols and less than 365 mg of ECGC's per day, however many capsules or green tea diet pills you have to take), your supplement probably won't help you lose weight unless it contains caffeine.
- If you're getting a full dose of green tea extract (at least 890 mg of green tea catechins/polyphenols and at least 365 mg of ECGCs per day), your supplement doesn't need caffeine to be effective.
- Green tea weight loss products work much better when you exercise, and the harder your exercise, the greater their added benefit in fat loss, and
- The benefits of green tea for weight loss and fat burning don't start for at least 24 hours after you take the first dose.
Also, unfortunately, you can drink green tea all day and still not get enough of the green tea antioxidants to affect weight loss.
Green tea ice cream, on the other hand, delivers a significant dose of green tea polyphenols and ECGCs--but you'll find the fat burning effect of the green tea in green tea ice cream is not quite enough to cover the extra calories and fat. For best results, use a green tea diet, cut back on calories, and exercise, the harder, the better.
You may also be interested in:When Green Tea Diets Don't Work
Abdul G Dulloo, Claudette Duret, Dorothée Rohrer, Lucien Girardier, Nouri Mensi, Marc Fathi, Philippe Chantre, and Jacques Vandermander.Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans. Am. J. Clinical Nutrition, Dec 1999; 70: 1040 - 1045.
Venables MC, Hulston CJ, Cox HR, Jeukendrup AE. Green tea extract ingestion, fat oxidation, and glucose tolerance in healthy humans. Am J Clin Nutr. 2008 Mar;87(3):778-84.