Just started doing this and I love it. Just brew 1-2 bags of green tea in a little bit of really hot water. wait 10+ mins, then dump it into a larger glass bottle (sobe bottles work well). then add some kind of sugar free juice (lemonade, orangeade etc) or just add 3-4 packets of splenda. then fill the rest with water and refrigerate. each bottle should now contain approximately: 100mg caffeine 1-2g carbs, 10 or less calories 300-400mg antioxidants vit C or anything else that was in the added juice i drink these things all day long. definitely great for cutting. very cheap too. and great-tasting.