It doesn't work. I tried it myself. In summer, I tie my arms and legs and do exercises. I'm sweating all over. But I think all the water has been drained. I'll come back after eating a little. You are right. If it is pricked, the pores of the skin will not breathe or metabolize. Losing weight like this for a long time is definitely bad for metabolism. In fact, the best way to lose weight is to exercise more, eat less sweets and eat more light ones. Eat more fruits.