As the years go on, the percentage of Americans and other first world countries' citizens who have unhealthy lifestyles is rising. One-third of the world is overweight or worse and is usually self-inflicted.
Once people are obese they are used to eating unhealthily and don't want to stop. While a lot of energy is used to move a heavier body, obese people are used to large quantities of food and continue to live an unhealthy lifestyle due to their own decisions. Obesity is not a disease, as it is self-inflicted.
When someone smokes regularly and gets cancer, is their cancer not a disease simply because it was self-inflicted? Just because the person's lifestyle was the reason that they are struck with a condition doesn't make it any less of a disease.
[P1] Obesity is due to individuals' overeating, not a disease.
Rejecting the premises
[Rejecting P1] Diseases inflicted by oneself are just as valid as those naturally occurring. Obesity is a disease.