Flavor does not matter, presentation does not matter but the food shouldn’t make you sick, and should ideally have enough calories per day for the average person to survive (2000 kcal min).
Edit: I am not in any danger of starving or malnutrition, nor am I insolvent. I’m mainly asking this question out of curiosity on how people would approach a solution :)
For my government mandated starvation month I picked potatoes and rice, just 2 cups of rice and a potato or two a day helps me… enough… rice for a 50lbs bag is around 40 bucks and potatoes for 10 pounds is around 5 bucks.