I'm doing MWL, not Mary's Mini, and I eat both rice and potatoes. But something Autumn said just hit me. Rice, especially brown rice, is acid producing (white rice less acid producing) and potatoes are alkaline producing. So it makes sense that potatoes are better for inflammation-related issues and would make the joints feel better. Thanks, Autumn, for raising that issue.
Lately, I've been on a smashed potato kick. I do a 50/50 blend of sweet potatoes (Not Yams!) and Yukon Golds. It's become a breakfast staple during the work week with green beans added.