As the name implies, chestnuts are nuts, so you can feel free to include them as part of your Paleo lifestyle. As with all nuts, though, chestnuts should be eaten in moderation.
Paleo and the Glycemic Index
Chestnuts are very high in carbs and don’t contain as much fat as other nuts to balance the glycemic load. As a result, even a handful can cause a spike in blood sugar, so people who are sensitive to that kind of thing might want to stay away from chestnuts.
On the other hand, if you’re looking for a Paleo-friendly way to replenish those glycogen stores after a heavy workout, then chestnuts are a great way to go.
Paleo and Phytic Acid
Chestnuts are also relatively low in phytic acid, meaning you can have your chestnuts and eat them too without worrying about any interference with mineral absorption.
Mark Sisson addressed the issue of whether or not chestnuts could be considered part of a Primal-friendly lifestyle on his blog.