There's the true God and false gods. Your stomach can be a god. If you are a big, fat, greedy pig that could be the name of your religion rather than a description of yourself.
(Philippians 3:19) . . .and their finish is destruction, and their god is their belly. . .
You may identify as 'atheist' but you'd still believe your stomach existed.
If I remember correctly, in America Christianity is not defined as a religion. I think it is described as a way of life. Another term for 'way of life' is 'diet'. So Christians are all on a diet.