Couch Potato

Based on Wiktionary, potato couch is a person who spends a lot of time sitting or lying down, often watching television, eating snacks or drinking alcohol.

Based on Wikipedia, potato couch is a person who lives a sedentary lifestyle which found in both developed and developing world. Sedentary activities include sitting, reading, watching television, playing games and computer use for much of the day with little or no vigorous physical exercise.