[ChrisV]

Well, OK, but when people talk about an "obesity epidemic" in the Western world, what they mean is people eating too much and not exercising enough. Of course you can be obese without that, but any classification of obesity as a disease would effectively classify being a lazy overeater as a disease.

The difference between that and, say, cirrhosis of the liver, another disease secondary to an addiction, is that you can't cure cirrhosis of the liver by not drinking anymore, whereas you can (in many cases) cure obesity by eating a good diet and getting your fat ass off the couch.