Sweat suits are common for athletes trying to make weight for their event.  In no way does a sweat suit help you burn more calories.  What you are really losing is water and the minute you start drinking again you will put those pounds back on.  If you goal is to lose weight and body fat remember this to lose 1 pound of fat you must burn 3500 calories.  So skip the suit and just balance your food intake and calorie burn so you are in a deficit of 500 calories per day and you will lose the weight safely each week.

No it does not.  You are only losing water, which you must soon replace anyway, or you will do harm to your body. Dehydration is dangerous.  Wear clothing that is comfortable for you. Don't force yourself to sweat more than is natural for your body. Dress in layers if you are training outdoors in colder weather, so you can subtract or later add back the layers to stay at a comfortable temperature. I often see people who are beginning an exercise program outside in winter with way too much clothing on.  Walking your dog on a cold winter morning reqires alot of warm clothing, but training in the same weather conditions does not, as long as you can get back inside where it is warm at the end of your workout.

Many people workout in rubber or plastic suits with the intention of dropping pounds fast. You may actually lose weight, but the weight loss is due mostly to perspiration and will be replaced as soon as you drink a few glasses of water. Some professional athletes who have to meet certain weight restrictions, such as boxers, may use these types of suits to help them shed water weight quickly. But, the suits do not increase the number of calories burned; they simply just make you sweat a ton. Dropping water weight does not have anything to do with dropping the amount of actual fat on the body and, in fact, can be dangerous. According to the American Heart Association, cardiovascular risk increases when the relative humidity rises above 70%, and the humidity in those suits hover around 100%. Other risks associated with the use of these suits are dehydration and overheating. Losing weight depends on the amount of calories burned compared to the amount of calories consumed. A suit while temporarily reducing the weight showing on the scale will not help you burn more calories which is key to true weight loss.