Question about additives to drinks to help boost weight loss?

are the crystal light metabolism+ green tea peach mango affective, with exercise, to help lose weight, or are they just packets of sugar that are useless? I used them two or three summers ago, and it dropped me from 220lbs to 170lbs, and I was only 5'5", and 12 Now, i have muscle, am 5'9", 15, and 205lbs caused by my huge and heavy frame. I intend to lose weight, by swimming a hour- hour 1/2 a day, but want to add a touch to burn more fat by using crystal light to boost my metabolism, but want to know that if they actually work and will work for me?