I know that green tea is very beneficial. What's better when it comes to weight loss, high grade or low grade? Which kinds of green tea are the best for weight loss?

The healthiest green tea contains the most catechins and theanine.
Catechins contain most of the antioxidants. Theanine is mainly known for calming your mind but has other health benefits.
High grade loose-leaf has the most catechins and theanine. Read the link below for the study behind this.
Incidentally they also have the highest caffeine, so don't drink too much. Caffeine, in combination with catechins and theanine, is highly effective for losing weight.
A high grade of 2 to 3 grams should brew you 3 cups, and that is equivalent to at least 6 teabags.
Because you can infuse 3 times, it probably works out cheaper, and taste MUCH better.
The second link contains two studies that show that combing green tea and an endurance exercise is high effective for burning fat.
Hope it helps
Julian

read tips on green tea and weight loss and much more on this site

It's called exercise.

Theres no evidence that green tea helps with weight loss. The reported health benefits comes from the antioxidants in it. With that, the high grade would be best. As for weight loss, diet and exercise are the best bets.

try herbal concentrate from www.myhealthabcmall.com, its by shapeworks and is the best green tea on the market. The inch loss is incredible with it.