There are much worse things than beans and rice. Feel free to indulge in those until you have greater control over your meals.
You can improve these by soaking or sprouting ala Weston A Price Foundation recommendations. Perhaps suggest to your gaolers that they buy Nourishing Traditions by Sally Fallon
Four years Primal with influences from Jaminet & Shanahan and a focus on being anti-inflammatory. Using Primal to treat CVD and prevent stents from blocking free of drugs.
Eat creatures nose-to-tail (animal, fowl, fish, crustacea, molluscs), a large variety of vegetables (raw, cooked and fermented, including safe starches), dairy (cheese & yoghurt), occasional fruit, cocoa, turmeric & red wine