Turn X -> Turn X+1: (Food on hand + production - consumption)*0.999 = food on hand next turn (round to nearest integer)

Turn 0 -> Turn 1: (0+30601-1134)*0.999 = 29437 food
Turn 1 -> Turn 2: (29437+30601-1134)*0.999 = 58846 food
Turn 2 -> Turn 3: (58846+30601-1134)*0.999 = 88225 food
Turn 3 -> Turn 4: (88225+30601-1134)*0.999 = 117574 food
Turn 4 -> Turn 5: (117574+30601-1134)*0.999 = 146894 food

Screenshot shows 146894. Don't see a problem?
Consumption doesn't show decay.