How to Eliminate Household Food Waste

I bought a bag of salad last week. Today I will discard most of it. I really meant to eat that salad. Why do I do these things?

Experts have researched the reasons why we buy products we never use. My bag of salad is not the usual problem. Professor Brian Wansink and two graduate students at the University of Illinois studied 412 homemakers and concluded that most unused products are purchased for a specific recipe or occasion. If not used immediately, products gravitate toward the back of the cupboard, where they will likely die a slow death. In an article published in 2000 in the Journal of Family and Consumer Sciences, they noted that up to 12 percent of purchased products are unused and eventually discarded.

Professor Wansink and his students found little evidence that advertising drove purchases of unused products. People tend to buy products with the intent to use them. They asked their subjects to find an item purchased at least six months ago and had not used. Most common were recipe ingredients, canned goods, household goods and entrees and hot side dishes. Each of these categories comprised from 15 to 18 percent of the products identified, and on average they were 2.7 years old.

Three reasons for buying a product—recipe, specific purpose and special occasion—accounted for 63 percent of the unused products. People abandoned products primarily because the reason for using them hadn't arisen. In one-third of cases a person didn't like the product. This seems perplexing, but it occurred often when a person bought a large size or a multi-pack, tried the product and abandoned the rest.

The salad incident illustrates just one problem associated with shopping. I thought about buying mouthwash on a trip to the grocery store last week, but decided we had enough. My wife disagreed. I didn't buy mouthwash. An hour later I learned that she was right. I wasn't the only one to make this mistake. People tend to overestimate low levels of household inventory and underestimate high levels, explained Pierre Chandon and Brian Wansink in an October 2006 in the Journal of Marketing.

A study conducted in 2003 estimated that families waste 14 percent of the meat, grain, fruit and vegetables they buy due to overstocking. Families could spend 12 percent less on these items by not overstocking. (It's not 14 percent. Trust me.)

The tricky part is learning how to better estimate what you have on hand. I didn't check how much mouthwash was on hand before shopping. I should have. Another solution is to order nonperishable products online. For example, Amazon's Subscribe & Save program is a great way to keep a constant supply of household products on hand.

Stores often price an item in multiples, such as 8 oranges for $4. People probably buy more when prices are expressed this way, according to a December 1998 paper by Wansink, Kent and Hoch in the Journal of Marketing Research. Purchase limits can similarly drive higher sales.

The flip side of letting something sit unused is using more than you need. A 1996 study by the Cornell University Food and Brand Lab showed that people tend to use more of a product when they get a large package, possibly at a lower unit price. You might use more mayonnaise if you have a large jar, whereas you might use less from a smaller container.

Now that you understand why we buy products and then abandon them, you can devise a strategy to decrease the likelihood of your doing this.

Try to buy substitutable products. For example, buy the more versatile product when given a choice.

Buy products for specific use as close as possible to the date when you plan to use them.

Buy multi-packs only if you will completely use them in a short time.

Think about your purchase when an item is priced by multiple units. If soup is on sale at 5 for $4, do you need five, or will three be enough? It's not a deal if you don't use all the product.

Everyone knows that you shouldn't shop when you're hungry. You may have to change your schedule if your habit is to shop on the way home from work.

Consider buying whole, fresh vegetables instead of precut, as the latter will spoil faster. For example, it's easy and cheap to buy a whole head of romaine lettuce and tear off a few leaves at a time.

Go ahead and buy a large container of a product if the price is right and you're sure you will use it. After you bring it home, avoid waste by taking care to use the recommended amount.

Serve leftovers as soon as possible, or freeze them if possible.

Keep an orderly refrigerator. This minimizes the chances of something hiding out, only to turn into a science project that you have to toss down the disposal.

Be aware of what's on hand, and plan to use it. If you're a baker, you can turn old bananas into banana bread. If you're not, then keep an eye on them and eat them before they turn brown.

Use cookbooks with food indexes. This allows you to look for uses of specific ingredients you have on hand.

Rotate products from the back to the front of shelves.

Actively plan uses for your abandoned products.

Make a quick decision after you've identified an abandoned product. Use it soon or give it away so that someone can use it.

Dispose of items more than two years old, as they are probably past their use date.