So how does green tea help you to lose weight? First let's be clear that all weight loss aids must be used in conjunction with a healthy eating plan and/or an exercise program. To lose weight, a person must either eat less or exercise more. Nothing can help a person to lose weight if they keep on adding more and more fats and sugars to their diet and become less and less active.
Most weight loss aids work either by reducing the appetite, so that a person eats less, or by increasing the calorific output so that they burn more calories. Research studies have shown that green tea has the second effect: it is believed to help you to burn more calories by increasing the metabolic rate.
It does this by stimulating the body's thermogenesis process, which turns fat into energy. So using green tea for weight loss is believed to help your body burn fat. It works a little like the drug ephidrine but is not considered to have the same risks for heart health. Nevertheless, you should consult with a doctor before taking green tea for weight loss, especially if you have heart problems or other heath issues.
In theory, green tea can have a weight loss effect even if you do not change your diet. However, in practice, this effect would be slow, and there is a risk that a person who was not paying attention to their diet would simply eat more to compensate for the energy that is burned. So it is important to exercise some control around food and at least be sure that your calorie consumption has not increased.
You might also want to apply that extra energy by starting an exercise program. Regular exercise can assist with weight loss in two ways: first by burning calories while you exercise, and second by increasing the metabolic rate so that there is a slight increase in calories burned even when the body is at rest.
A good time to take green tea for weight loss is around 30-60 minutes before a meal. It does contain caffeine so it is best to reduce your consumption of coffee or regular tea by replacing those drinks with green tea. If you don't usually consume any caffeine, it is better not to drink green tea after midday so that it does not affect your sleep. Decaffeinated green tea is available but studies suggest that the fat-burning catechin is often removed along with the caffeine so using decaffeinated green tea for weight loss is not so effective.