Nutrition: Sweet Potato (A Paleo Exception)
Those who adhere strictly to a Paleo style diet can find their recovery or energy levels for activity can be hampered (especially) if they opt for ultra-low carbohydrate intake.
It is important to fuel our bodies for activity, and to support recovery. But it is often confusing as to what options are available to us as paleo or primal dieters who don't want to rely on high glycaemic foods (pasta, potatoes, rice, etc) to perform this task?
Well one alternative includes root vegetables (tubers) - such as yams and sweet potatoes. These are neolithic foods but can be important as a means of achieving healthier calorific density in moderation. Below I consider some benefits of the sweet potato.
The sweet potato is a moderate GI (glycaemic index) carbohydrate and is very high in Vitamin A (a fat-soluble antioxidant). Vitamin A (beta-carotene) is what gives sweet potatoes the rich orange colour (some sweet potatoes are purple in colour).
To maximise absorption of vitamin A ensure you have adequate fat with your meal to ensure the body is better able to utilise this antioxidant.
Interestingly a study several years ago of 10,000 Finnish smokers found that those with higher levels of Vitamin A (beta-carotene) in the blood had a lower incidence of lung cancer. This was only the case with Vitamin A from natural sources though, not that coming from synthetic vitamin supplementation where lung cancer rates where actually found to be higher!  Another reason to stick to natural sources for antioxidants!
In Loren Cordain's book "Paleo Diet For Athletes" the sweet potato is also considered as one of the better options for recovery from extended endurance work. This book goes into great detail of nutrition for pre-, during and post-activity.
The sweet potato also includes Vitamin C, E, B6 - the micronutrients manganese, copper and traces of potassium and iron. Anthocyanin is a colour related pigment which studies have shown to have anti-inflammatory properties another property supporting one's recovery from activity.
Here's a recipe for Sweet Potato Chips (using coconut oil for adequate fat intake).
 Effects of anthocyanin-rich purple potato flakes on antioxidant status in F344 rats fed a cholesterol-rich diet. Br J Nutr. 2007 Nov;98(5):914-21. Han KH, Matsumoto A, Shimada K et al.