But what does "boost sales" mean to shoppers?--- a population of shoppers buys so many chocolate bars one week. The next week there's a promotion and they buy, say 10% more. Where does that extra chocolate go? It's not that it balances out in sales in future weeks, because that wouldn't be "boosting sales", and food companies wouldn't bother if there was no advantage. The extra chocolate gets eaten by the population of shoppers in addition to their normal intake!

This is one way in which people are slowly trained to eat more to the benefit of food companies.

If promotions were removed, the normal price of product should be lower. And because the population is eating 10% less, it might not be much more expensive for them to do without promotions.