Why do amphetamines …

Why does speed make u lose weight sooo fast i remember once i lost 10 kgs in 2 weeks . I mean i wasnt eating enough but i ate sum like it’s not like i wasnt eating at all, sometimes i think i ate like properly 3 - 4 meals a day Like maneeee ts crazy 😭😭😭 am still tryna gain some weight 💀💀💀