Rice (specially white rice), potatoes and sweet potatoes are some of the better best accepted carb sources, though they are not strictly paleo. Lentils are often better tolerated than other legumes, and you should try to have your lentils, or any other legume soaked for 24 hours to reduce toxin content. Socially the best reason to provide is that this improves your digestion. Whether you should choose rice or lentils, I think it comes down to which food you tolerate better, individually.

Rice (specially white rice), potatoes and sweet potatoes are some of the better accepted carb sources, though they are not strictly paleo. Lentils are often better tolerated than other legumes, and you should try to have your lentils, or any other legume soaked for 24 hours to reduce toxin content. Socially the best reason to provide is that this improves your digestion. Whether you should choose rice or lentils, I think it comes down to which food you tolerate better, individually.