The Expected Marginal Benefits of Drinking: in moderation, can it help keep you slim?

Can drinking help keep you slim? From the Daily Mail (h/t to BenS):

People who drink moderately every day are significantly less likely to become obese in later life than teetotallers, researchers found.

However, the image of the potbellied ten-pint-a-night man still holds true - those who indulge in binge or heavy drinking are 46 per cent more likely to become obese than those who don't touch a drop.

So, it is drinking in moderation (not to excess) that might be associated with a lower probability of obesity. And it is far from clear that there is a direct causal link.

If there is a causal link between drinking and weight control, though, it appears that the expected marginal benefit is positive for the first drink or so, but then turns negative.

In my own case, I know that the causal relationship does not work this way. Once I have even one drink, my inhibitions are greatly impaired, and I start eating any junk food I can get my hands on. But if there is nothing of interest in the house, I'm happy to run to the variety store (a half block away) in my bathrobe and slippers for some junk food.

Even in the winter.