Well the food addiction or sedentariness addiction diagnosis are a lot more controversial than a heroin addiction diagnosis, though I can see how they have some things in common. I think labelling any observable manifestation of poor impulse control as a medical addiction is more of a social trend than a legitimate scientific discovery.

The bigger difference though is that we all eat food, and for most of us includes at least some absolutely delicious food that would be incredibly unhealthy to eat in large quantities. We’re all (more or less) exposed to the “addictive substance”, it’s just some people have the ability to deprive ourselves constantly indulging that impulse, while others don’t. We don’t however, need to take small doses of heroin every day to survive.