What is a possible sign of Couvade syndrome in a pregnant man's behavior?

Couvade syndrome, often referred to as "sympathy pregnancy," involves a partner experiencing physical or psychological symptoms similar to those of a pregnant person. In the context of this question, weight gain is a notable sign of Couvade syndrome among expectant partners.

This phenomenon can be attributed to several factors, including changes in lifestyle, emotional stressors, and the psychological impact of the pregnancy on the partner. These individuals may begin to mimic their pregnant partner's behaviors, including eating habits, which can lead to weight gain. It reflects a deep emotional connection and empathy towards their partner experiencing the physical changes of pregnancy.

While the other options might reflect various lifestyle changes or emotional responses, weight gain specifically resonates with the physical manifestations of sympathizing with a partner's pregnancy, thus making it a prominent sign of Couvade syndrome.