You are confusing social pressure with environmental changes. marcus_holmes correctly points out that in some cultures men are under more pressure to fit into

You are confusing social pressure with environmental changes. marcus_holmes correctly points out that in some cultures men are under more pressure to fit into a gender stereotype around being really muscular. (And it's well known that women receive even more pressure to be slim and so on) This is true regardless of the worsening food quality and availability making people fat. Or environmental factors reducing sperm count and so on.