Some things science get wrong. Does observing the effects of "a particle" prove the existence of "a particle"? The answer may be know at first, but with what degree of certainty, or perhaps it just suggests existence. That too may depend on how we define existence.
Religion, on the other hand, says seeing the effect of the belief of god proves the existence of god, while what it proves is the effect of believing, not existence and that cannot be disputed.
So is food addicting, or do people just act like sugar is addicting to some? The best test for this one is to take the sugar away and watch the discomfort for the first while. If that is not withdrawal, I do not know what is.
So does existence apply to all, or the real, or just the physical world? So to get back to the ultimate question, if god is just a concept, residing beyond space and time, but the belief has an effect on those that believe, does god exist or does he only exist in the mind of the believer? For sure there is no physical existence, so it all depends on the definition of existence. So god does not exist in the real world, nor does mathematics! That does not seem right. So gods do not exist in the physical world, yet he or they exist in the conceptual world. What could be simpler or clearer? God does not exist in the physical world, and only in the conceptual world.
I am an easy to fatten person, a little bit of food is all I need, that is to say that my personal Attwater factors are high. We have high efficiency livestock so why not humans in the human genetic mix? Consumption of any sugar is over-consumption for me. Sugar addiction is real. Emotional eating is real. Obsessive compulsive behavior in eating occurs in me. What other food/overeating/ drivers are there?
SO if there is no god, how does OA help some people? It gives them something to obsess over, and that take them directly to Schwartz step three, which is one solution to the obsession without understanding the problem.