The yolks of eggs specifically are a good source of Zinc. The whites, not so much, which is why you’re missing out on a lot if you only opt for egg whites. Egg yolks contain all of the vitamins that are in an egg as well, so by eating the yolk you may be getting more fat but you’re also getting Vitamins A, E, D and K, as well as additional amounts of minerals, which more than make up for any potential drawbacks.
As if you needed any additional reasons to eat chocolate, here’s one more. You’re getting quite a bit of Zinc in chocolate, but of course it’s also pretty high in calories so you don’t want to overdo it. There are antioxidants in dark chocolate that you don’t get with milk chocolate, and you end up avoiding a lot of the sugar and added fat if you stick to dark chocolate.