Would you like to cut your grocery bill by 15 percent? Stop wasting food.

It sounds simple don't throw away food that you've bought with hard-earned dollars.

But Americans do just that every day. A study by the University of Arizona estimates that we throw away nearly 15 percent of our grocery purchases every week, unopened and unused. (If you spend $400 a month on food, that's about $60 going into the landfill each month. Wouldn't you like an extra $60 in your wallet?) Many of these products are within their expiration date and perfectly safe to eat. The remainder are items that have spoiled on our pantry or refrigerator shelves.

Waste not, want not

The first rule to curbing food waste: If you won't eat it, preserve it, or give it away, don't buy it.

You have lots of options when it comes to saving or disposing of excess food. You could eat it, of course. We're in peak tomato season right now, which means that we're eating tomatoes often in soup, sandwiches, salads, on burgers, and plain with a dash of salt.

You could also preserve excess food. Nearly all meats or vegetables freeze well we often buy 5-pound containers of beef or chicken to divide into meal-sized portions and freeze. We also buy bread on sale and stick it in the freezer for later.

If you're feeling ambitious, try canning or drying foods. This requires an investment of time and equipment, but you'll get better long-term results.

Finally, you could give food away. If you pick up a large quantity of items on sale, but later realize you will never eat all of it before it expires, donate it to a food pantry or ask your friends or neighbors if they'd like it. Cereal, tuna, soup, and other shelf-stable foods are great to share, as are in-season vegetables like tomatoes.

Get creative

I've expressed my enthusiasm for leftovers before. Using leftovers is a great time- and money-saver. But if leftovers tend to linger in your refrigerator well past their prime, you've got two options: prepare less food at mealtime, or make a better effort to utilize leftovers in your meal plans.

The first step to utilizing leftovers is to label them! You'll want to eat leftover food within a few days of preparing it, so write the date and contents ("Meatloaf, Tuesday") on a piece of masking tape and start labeling containers. Place the freshest leftovers to the back of the refrigerator, and encourage picky eaters to choose from the foods near the front first.

Can't use leftovers for lunch? Start "using up" foods during dinner. That leftover roast chicken would make a great sandwich a few nights later, or could be the start of a wonderful soup. You can also refrigerate foods for two-three nights in a row and then declare "leftover night" anything in the fridge is fair game, but the chef is stepping out of the kitchen. Fire up the microwave, heat up leftovers on a plate, and use up foods before they go to waste.

It's a guaranteed timesaver, and think of your lowered food bill!