How about different hormones which drives hunger and outside of your conscious control, because you have a genetic predisposition to produce more of those?
I genuinely don't understand some people who talk like they have full conscious control over every minute of their day and their whole life.
Hormone signalling isn't control, if it were then society would cease to function and among many other terrible things you'd lose bodily autonomy as anyone who wanted to sleep with you and was strong enough to subdue you would do so every time they had the urge.
Actual daily levels of hormones or genetic predisposition have a huge effect on self-control or conscious control.
A relative of mine had a stroke which resulted in the loss of part of the brain. Most people don't have such a drastic stroke, but it's enough if you're born with a different gene and you have a slightly different connectivity in your cortex to not have as much self-control as the next person.