How does this vest works and make you sweat like crazy, burn more fat, produce heat and weight loss: Firstly by raising your core body temperature, so your body has to work far harder to cool down and maintain a healthy temp. (this is called to thermo regulate). This process causes the body to burn off at least 50% more fat because of the extra energy (increased energy expenditure) your body uses to cool down and maintain a healthy core temperature. Secondly they cause the body to produce a heavy profuse sweat. To create sweat your body uses up massive amounts of fat and energy and burns 0.7 calories for every gram you produce. Scientific testing shows an extra 300-800kcals can be used in a workout wearing a Sweatz Quick Weight Loss Vest. This actually burns off at least twice the amount of calories and fat, accelerating your quick weight loss to a tremendous level. Thirdly they put you straight into the fat burning zone which usually takes over 30mins. So your actually burning fat for your full workout instead of just the average 20mins of a 1hr session. This makes fat burning 3 times more effiecient. Fourthly When wearing the vest your metabolic rate is increased by roughly 30% giving you an extra 30% more fat burn whilst working out. Altogether they burn off at least twice the amount of fat and make you lose weight weight twice as fast