Craving chocolate. Chocolate contains neurotransmitters like phenylethylamine. This is the neurotransmitter that is very high when we are madly in love. Depression due to rejection( not correspondence from our love wishes) drops this levels causing depression. Unconsciously rejected lovers crave for chocolate. Also substances like theobromine and caffeine in chocolate are stimulants. Copders are not the only ones.
Caffeine, steroids. I do not believe that the premise of your question is correct. People with COPD taking steroids have a huge appetite. Some have mentioned caffeine in chocolate as a natural bronchodilator. This is a cute guess, but mostly unscientific. If it was the case, they would be drinking coffee all day long.