I know it's a no to the prawns until the higher plans. 100g of prawns has about 2g of fat in, no carbs though, and 17g of protein, and about 80 calories. Cod for example has about 0.8g of fat, 24g of protein, carbs and 105 calories per 100g. So it may be too much fat and not enough protein maybe, though that's a guess!