Here is a link from the website Natural News. Not exactly paleo but a good website.
(NaturalNews) More and more health reasons for eating dark chocolate keep coming in. Many will be pointed out here, then explained further in the sources indicated by numbers in parenthesis. But first, understand that organic dark chocolate brought into the market place under fair trade agreements is best.
Some of the major cheap chocolate producers use child slaves in Africa to pick cacao. The more dark the chocolate with less sugar, milk, and other ingredients, the closer it is to cacao. A range of at least 70% to 90% cacao in dark chocolate is both tasty and healthy.
Milk chocolate contains milk, which negates the health benefits, and sugar, which feeds cancer cells. Avoid it.
According to Dr. Debra Miller's statement in Chemistry Central Journal , "Cacao seeds are a 'Super Fruit' providing nutritive value beyond that of their macronutrient composition." (1)
Interestingly, one doesn't have to gorge lots of chocolate every day to get the health benefits. A little treat, like a square or two daily will support good health.
A study of almost 20,000 participants in Germany concluded that those who ate 7.5 grams of dark chocolate a day received most of the heart protection benefits of chocolate. Organic dark chocolate bars are usually 100 grams. (1)
Benefits of dark chocolate
1) Cardiac and stroke protection : Dark chocolate lowers blood pressure, which lowers risks of heart attacks and strokes. (1)
2) Reduces risk of colon cancer : Cocoa polyphenols from dark chocolate reduce the risk of colorectal cancer. This was determined in a study by the Science and Technology Institute of Food and Nutrition in Spain, which was published in the journal Molecular Nutrition. (2)
3) Healthy fats :The fat in chocolate does little to raise cholesterol. It contains abundant oleic acid, the type of fatty acid found in olive oil, which helps prevent heart disease and promote antioxidant activity. (3)
4) Enhances glucose metabolism : Dark chocolate (70% plus) candy bars inhibit blood sugar issues to help prevent diabetes and obesity. How's that for a surprise! (3)
5) Improves mood : Studies have shown that dark chocolate contains serotonin and increases endorphin production. It's a natural anti-depressant. (4)
6) Improves brain function : Nottingham University professor Ian MacDonald used MRI analysis to determine improved brain activity with people who had just consumed cocoa drinks. (4) Hopefully they didn't have to undergo too many MRI scans that would fry their brains!
7) Eases PMS issues : Here's a hint for husbands and boyfriends to give dark chocolate to your wives and lady friends. (5)
There you have it: many reasons to enjoy organic dark chocolate that is at least 70% cacao. There are brands with 80% to 90% as well. These aren't your kiddy chocolates with lots of sugar or milk or creamy nugget fillings, etc. They are semi-sweet at best.
The more bitter the better. It's not difficult to get used to if you really like chocolate. Enjoy chocolate with the knowledge that it's actually good for you.