Amphetamines, commonly known as "speed", and adrenaline activate the body in a similar way. Breathing and heart rate speed up, the pupils widen, blood pressure increases, and appetite is suppressed. Overuse of speed (too much at once or too often) can cause heart attacks. I almost don't even need to explain why obesity is bad. Being fat puts incredible strain on the heart and can cause heart attacks. Would it be safe to sell amphetamines to fat people so they can lose weight? An online friend of mine (who uses drugs) said a friend of his lost a good 100 pounds (about 45kg) in about 3 months after he started taking speed specifically to lose weight (since he was about 300 pounds). Obviously speed also causes strain on the heart, but consider which is worse; taking speed for 3 months, or being 100lbs overweight for 30 years. A product used to be sold in the US that was similar to speed, it was called Ephedra or Ma huang. The active ingredient in Ephedra was ephedrine, the chemical which methylamphetamine "meth" is made from. Amphetamines (speed) should not be confused with methylamphetamines (meth) because that extra methyl group makes the drug easier to absorb. Comparing speed to meth is like comparing beer to vodka, they are similar but one is much more powerful. Those weird people at raves are on speed. Those crazy people who would kill for money are on meth (or some other really bad drug). With all that said, should amphetamines (in lower concentrations) be legal so people can lose weight?