i would suggest genuine wild rice, not the store bought pretendo wild rice, but the real deal. this rice is grown by mother nature in lakes in minnesota, and harvested sustainably by native american tribes. be sure to soak it in good water for about 20 - 24 hours before cooking. you can then cook it, or you can allow it to sprout for a few days if you like. once sprouted you can still cook it on low heat, its really a wonderfully nutritious treat, the healthiest carbs around as far as i am concerned.
sweet potatoes are fine too, but they are high in sugar. the real wild rice has complex, slow release carbs, the kind you want. you can also make rice milk with this rice by adding some water, rice, Sea Salt , vanilla, cinnamon, and your favorite sweetener (i like agave nectar) in a blender and blending away, its really wonderful.
your recipe with the chia, astragalus, rhodiola and maca sounds really wonderful, great idea!