What Could Cause Unintended Weight Loss Without Dieting?

I am a 55 year old overweight female. On Aug 29 I saw mt doctor for a annual check up and I was 221 pounds. Today I am 205 pounds. I am not dieting, but have had a loss of appetite and I am drinking a lot of water. I have cut out caffeine and alcohol with exception of 1-2 glasses of red wine a week. While I like the weight loss, I am concerned it may be an indication of something else wrong