I will grant that the US Constitution gives no such authority. But I do not think the state of New York derives any authority at all from it, since it is an enumeration of Federal powers only. As far as I know there might be something in New York's constitution that the law may violate, and I hope there is. As for the 14th Amendment's equal protection clause, I can't see that it applies.
As for equal protection, this applies in this case also because the law didn't apply to all sugary(I hate that expression, actually)drinks equally, therefore the manufacturers of certain drinks were not afforded equal protection, or should I say some manufacturers were held above the law, which amounts to the same thing.