Big Stores, Big Bellies?

How supermarkets and warehouse clubs make healthy shopping tricky

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Due to their convenience and often cheaper prices, big-box stores, warehouse clubs, and standard supermarket chains have become popular alternatives to specialty chains like Trader Joe's and Whole Foods, and small, local markets. Many of the grocery goliaths even offer natural, fresh, and organic options for the health-conscious shopper.

Chelsea Bush
Chelsea Bush
But there could be downsides to getting your groceries at stores like Costco, Wal-Mart, and Target. Your grocery store can influence how much you buy, how much you eat, and whether you choose the baked pita chips or the Doritos. Here are some healthy-eating saboteurs you might not have bargained for.

Doubling Up at Wholesale Clubs

Membership stores are the grocery equivalent of a buffet: We buy more to justify our membership fee and to feel like we're getting a good deal; then we eat more so as to not waste the surplus.

While there may be nothing wrong with stocking up on milk and poultry, a trip to Sam's Club or Costco usually invites more than healthy staples into our carts. When shopping to get our money's worth, we're more likely to buy foods we don't need or wouldn't ordinarily purchase, Cornell University professor Brian Wansink writes in his book Mindless Eating. Frozen pot stickers, a jumbo bag of Chex Mix, a 100-pack of granola bars—a few last-minute grabs will help solidify the "savings." (Or in my case, I indulge because, what the heck, it's a good price.)

After the shopping spree to recoup a membership fee, there's the burden of having to eat all that food. People eat stockpiled foods at almost twice the normal rate, Wansink's studies have found. For one, there's a race to eat it before it spoils. Next, we're dealing with jumbo-size quantities, which, just like jumbo-size restaurant servings, tend to skew our portion sense.

We also have an odd compulsion to preserve the "norm," Wansink discovered. If we're used to seeing one box of cereal in the cupboard, and suddenly we have three, we'll eat more in order to whittle our stock back to the baseline. The pattern of stockpiling and gorging is most common among new club members, he notes.

The 10 for $10 Scheme

Thanks to clever pricing strategies, you don't have to shop at warehouse stores to come home with piles of food. A group of studies published in the Journal of Marketing Research found that a suggestion to buy in multiples—whether a "10 for $10" price label or a "limit 10 per customer" tag—leads the average consumer to buy more. In four studies across 89 stores, sales rose by 30 percent when multi-unit pricing was used.

With pricing in multiples, it's possible that some consumers are under the impression that they must buy the listed quantity in order to get the sale price. But, said the researchers, it's unlikely that this is always the case. Rather, it seems that even if we know we can buy one for $1, we unconsciously stock up on the suggested amount, or at least grab a couple of extras in order to take full advantage of the bargain.

While health-focused stores use quantity limits and multi-unit pricing, too, these "sales" seem less prevalent. I rarely see rows of neon tags at the local and organic markets in my area.

Store Layouts and "Dwell Time"

Marketing research (of the hidden-camera variety) has found that the longer we spend in a store, the more we buy. Thus, displays and signage, even food samples, are strategically placed to increase "product exposure" and "shopper engagement"—in other words, to keep us wandering around until we forget we ever had a shopping plan.

Granted, every grocery store is designed to prolong customer "dwell time," but we'll spend much more time in a big store than a small one. We have to travel farther to get to the necessities, which are typically located in the back of the store. Big-box stores and supermarkets also seem to create more distractions of the junk-food kind; towers of chips, cookies, and 12-packs of soda seem to abound in the impulse-buy spots.

Is it also possible that the long lines, crowded aisles, and option-overload of a typical megastore shopping experience have a negative effect on our food choice? Chaos and stress have been shown to dull our ability to make good decisions, not to mention trigger cravings, so it would certainly seem so. In which case, even if we escape the siren call of Super Bowl snack displays and point-of-purchase candy at a Costco or Wal-Mart, store exits are flanked by fast-food joints to catch us on the way out.

Tips for Healthy Shopping at Any Store

With a firm shopping list and a strategic navigation plan, you can cut your dwell time in any grocery store and stick to the items and quantities you need. If you do buy in bulk, Wansink suggests hiding the extras when you get home. Another tip: Even if you're only buying a few items, use a shopping cart instead of a hand basket. A recent study found that people tend to make indulgent purchases when selection involves bringing an item toward the body, whereas we make healthier choices when extending the item away from us to place it in a cart. Though shopping with a flatbed might be another story.

Hungry for more? Write to eatandrun@usnews.com with your questions, concerns, and feedback.

Chelsea Bush is a Utah-based journalist on a mission to tap the secrets of psychology to end laziness, cheeseburger addictions, and other annoying habits that keep us flabby. Join the cause here in the comments and at @chelseawriting.