You are likely gaining a tolerance to the Niacin. I wouldn't recommend taking more than 250mg daily, though. I would instead take it longer after the meal or not with a meal at all. For me personally, I don't get the flush if I take Niacin with food at all. You could probably get away with cutting the 250mg tablets in half and taking them at a different time of day, or wait to flush before you eat your meal.