Unhealthy impact

Supermarkets can have an impact on your health, through the shopping choices they prompt you to make.

Unhealthy price promotion

Fruit and vegetables make up too small a proportion of price promotions and advertising.

According to a 2005 Ministry of Health report, the total advertising spend by the food industry on chocolate, confectionery and soft drinks was over nine times the amount spent on advertising fruit and vegetables.

Price promotions encourage you to buy more. A US study from the University of Illinois found that people buy more of an item if the sign uses multiple pricing such as "two for $1", rather than "50 cents each". Quantity limits like "four per customer" also promote multiple purchases.

A New Zealand study published in 2006 reported the effect on shoppers of different price discount styles.

One finding was that for goods like tinned spaghetti, which are relatively cheap and easy to stockpile, volume discounting was more attractive than a monetary discount. If using a volume promotion, "buy one get one free" promotions are likely to be more effective than "two for the price of one" promotions.

Supermarkets always have some fruit and vegetables on special, but they rarely have specials encouraging us to buy extra fruit and vegetables.

Big sellers

High-sugar and high-fat big sellers are often priced to encourage you to buy bigger sizes of a product. This encourages you to make financial savings, but these may come at the cost of your and your family's waistline and health.

Take Coca-Cola – there's often a large financial disincentive to buy the smaller bottle of Coke. The same goes for chocolate. It's a lot cheaper for each 50g of chocolate, if you buy the king-size bar.

Gondola ends

The ends of aisles are often the most profitable spots in the store - filled with specials and impulse buys. You'll often see junk food like soft drink, chocolate and chippies on offer.

Supermarkets also entice you to stock up on beer and wine specials.

Unhealthy check-outs

How many times have you given in to your kids at the check-out and bought them a chocolate bar?

An Australian survey showed that 80 percent of responding parents said they were always or sometimes pestered by their children to buy junk food at the check-out.

In UK supermarkets, Waitrose and Tesco, all the checkouts are completely snack- and confectionery-free.

Unfortunately, that's not the case in New Zealand. We'd like to see more confectionery-free check-outs in New Zealand so parents can avoid the pester power.

Loss leaders

Supermarkets, especially those with strong local competition, offer "loss leaders". These are heavily discounted products, advertised to get you in the door. They're sold at or below cost - and the cunning plan is for you to pick up a few extra items while you're buying your bargains.