You should not insult the weight of others.
Kate is at the gym working out with a friend of her's who wants to lose weight.
Kate wants to motivate her friend to push harder.
Kate focuses on health related goals in order to motivate her friend.
Kate brings up how heavy her friend is in order to get her pumped up.
Kate's friend is reminded of why she wants to lose the weight and tries harder.
Kate's friend feels even more insecure about the extra weight.