According to this meta questionthis meta question, "general weight loss questions" are considered on-topic, provided, of course, that they follow the general SE rules. This makes for the scope of the site rather confusing, especially given the title of "Fitness and Nutrition" (which, to me, and, evidently, many others, means that nutrition questions are fair game, even if they don't relate to fitness), when nutrition questions are marked as off-topic. To further confuse things, there are also blog entries like this one that cover "general nutrition" and not just "nutrition as it relates to fitness."
That said, fitness and nutrition typically go hand in hand, even if a given person is not immediately concerned with one while focusing on the other.
I think the FAQ/scope of the site should be tweaked to allow for more general nutrition questions would provide more consistency, recognize that both complement each other well enough, and be more prudent, overall.
