Apparel made of neoprene, the material that scuba suits are made of, increases body temperature locally. So neoprene pants make you sweat more when working out. While this can cause an immediate loss of water weight, rehydrating or eating a meal brings that weight right back.
Safety in Question
The National Athletic Trainers Association discourages the use of plastic suits for weight loss because it increases the risk of heat illnesses including muscle cramps, heat stroke, heat exhaustion and heat syncope, or fainting. The association recommends that athletes work out in loose-fitting, absorbent clothing that allows for the body to cool properly. And an article in the "Postgraduate Medical Journal" by researchers at the Department of Medicine at Pembrokeshire Health Trust in Wales found neoprene pants to be linked to a risk of gastrointestinal problems, contact dermatitis and deep vein thrombosis.
The only safe way to weight loss entails a healthy, balanced diet blended with strength training and cardio. The American College of Sports Medicine recommends at least 250 to 300 minutes of cardiovascular exercise a week and two days of resistance exercise to lose weight.