Almost four years sober, I have another theory on this.... as it still happens to me.
The original "gateway drug" for me was sugar. Long before I ever smoked or ate a drug, or had my first taste of alcohol, I was behaving in addictive ways toward sugar.
I binged on it.
I hid it.
I hoarded it.
I lied about it.
Sugar - it has been shown - lights up the same 'pleasure centers' of addiction just like other drugs do.
I no longer do drugs or drink - but that part of my brain which seeks pleasure and the addictive high is still in there, long-conditioned to the rewards of sugar.
I've never really given it much concern but in the past year I've watched more consciously as I've slipped into sugar binges, cravings, and behaviors toward sugar that I can only admit are addictive in nature. I'm concerned about sugar's effect on my long term health and overall wellness and am *trying* to manage it more carefully. But, as with other attempts at moderation, I wonder if I'll have to eliminate it entirely.
Anyway - that's been my experience. I think that the body's need for sugar is one side of it, but in our over-sugared society I believe the addicted brain begins forming around the sugar-high reward from an early age and those of us with addiction issues are likely to be more susceptible to legitimate sugar addiction than others might be.