> you could easily survive on chocolate alone for years

Seems like quite an extreme claim. I'm not disagreeing, I simply don't know, but is this surviving with no ill effects (rickets for example) or surviving in the sense of just being alive?

Do you have any references?

I suspect it would be "just being alive" because I imagine eating chocolate alone would come with a whole host of other problems over a long period of time (including scurvy). I'm not sure vitamin D deficiency would be an issue if you were stranded on an island with limited shelter.

However, there is something to be said for chocolate's nutritional value in special circumstances. Most modern military rations include chocolate or chocolate-flavored items in some form as a significant part of their caloric value (predominantly fats and carbohydrates, even for the flavored items, as your OP mentioned). Aside from its propensity to melt, its size and weight make it somewhat convenient to carry on patrol and for lightweight rations, calorie-dense items are important.

I'm sure there's probably some literature on its use in rations that may be a good starting point, but as far as I remember from watching far too much Steve1989 on YT [1], most of the historic survival rations--think plane crashes--tended to rely on candy, malted milk tablets, or compressed oatmeal/cornflake bars rather than chocolate.

I've linked his channel below because I think you might find it fascinating.

[1] https://www.youtube.com/channel/UC2I6Et1JkidnnbWgJFiMeHA/vid...

One of my friends found a whole carton of chocolate eggs while dumpster diving at college, and spent his break living off of the eggs.

Bathroom time must be interesting.