Like a lot of things chocolate is a mixed bag. It contains beneficial antioxidants but also contains caffeine, which isn't a bad thing in moderation but for some people can be too stimulating. All chocolate we eat in bars has sugar in it, in varying amounts, and sugar isn't good for you, but in moderation isn't terrible, it's only really bad if you eat too much of it. You can buy pure dark chocolate if you want to eat it -- it's quite bitter -- in the form of bakers chocolate, but again, it doesn't taste very good. Traditionally, and this is interesting, native people who lived with chocolate before Europeans turned it into a candy didn't really eat it, they used it mainly as an herbal treatment for stomach problems. I don't really see why anyone would be "craving" magnesium and why chocolate has anything to do with that -- there are many more healthful foods that have plenty of magnesium in it, such as greens, but you don't mention craving greens. You crave chocolate because with sugar added it tastes really really good. In moderation, it's fine. Go overboard, and it's not. As for its benefit to heart health, you wouldn't really want to eat enough of it to do that even if it does that, and we don't know that it does that. There are beneficial antioxidants in many foods, and many foods that are much higher in them than chocolate. Nobody has to eat chocolate to be healthy. Do you actually know you have a magnesium deficiency? Did a professional test you and tell you that? I'm guessing not. But many people do lack magnesium for two reasons: they don't like green leafy vegetables, or they consume too much dairy -- dairy is very high in calcium but deficient in magnesium, and since the two must be in electrical balance in the body, eating too much dairy can and often does throw off magnesium levels.