poundcake

n.磅蛋糕

if you diet too strongly, it won't be long before you're laying prostrate on the couch, Sara Lee poundcake in one hand and a 20 ounce bottle of Mountain Dew in the other. 作者的意思是，如果节食过了头，就会受不了，然后就会躺倒在沙发上，重新大吃大喝起来。从原文来看，没有虚脱的意思，应该是受不了节食的痛苦和美食的诱惑，而恢复原状。