smile

I would say that a smile can give someone, moral strength, moral support, better disposition, better outlook, encouragement and simnilar positive effects on someone to whom a smile is given but I don't think it gives physical strength like what you get from eating, exercise,etc. to the one who smiles. Maybe it could have apsychological effect which makes the one you smiled at feel strong as a bull or an elephant but it does notactually give physical strength.

smiling only strengthens you soul, your spirit. it boost your confidence, attitude, self-worth. in that note, i think foods and exercise can't give you that. although exercise can boost your confidence also by having a well-built body. so, i am going to agree with you here.