text: i want to reduce my thight size and increase my height...what should i do? which diet should i choose?...is it hi-fibre increasing your height is impossible unless you are still a growing child/ young adult. generally, we stop growing around the age of 21, though occasional growth spurts have been reported in older people. but they can't be controled i'm afraid!   how about high heels? they lengthen the legs and make your legs look slimmer!   with regards to thigh size, just eat in moderation, and do leg exercises. a great one is to lie on your back, hold your legs in the air above you (straight, at about 45 degrees from the ground) and open and close them.