Longitudinal study of the effects of price and promotion incentives on purchases of unhealthy foods: evidence for restricting food promotions.

For all product categories analysed (biscuits, crisps and savoury snacks), household purchasing is most responsive to any volume promotion. Therefore, assuming the response of consumers to incentives remains constant following legislation, the most effective policy instrument to reduce the calorie intake from these products may be a ban on volume promotions.