Drinking water can help you lose weight, whether you're restricting your calories or not. Consuming 2 cups of water before a meal helped a group of obese adults lose 2 pounds over a 12-week period without making any other changes to their usual intake, according to a 2015 clinical study published in Obesity.
How many tea bags should you use to make a half gallon of iced tea? One gallon is about 128 ounces, so if one tea bag is good for 10 oz  of water, then about 10 teabags is good for a gallon. Start with 10  and adjust accordingly with water.
Given that 4 quarts is equal to a gallon, you'd need 16 tea bags for their tea bags. Their instructions recommend you boil a lesser amount of water (one quart for example in 16 tea bags), then after the steeping time, you would add water to the required one gallon.