Americans waste almost half of their food, according to a new report.

Food waste is becoming a major American problem. Americans waste an astounding 40 percent of their food, a statistic that has doubled since 1974, according to research published in the journal PLoS ONE found. And it's not just trashed food that gets wasted, but also tons of the food and water used to grow, harvest, process, and transport the food, the study authors say. "Food waste in America has become a very large problem that significantly drains national resources," explains study coauthor Kevin Hall, PhD, of the National Institute of Diabetes and Digestive and Kidney Diseases. For example, about one quarter of the total consumption of fresh water in the United States is used to produce food that is not eaten, the study authors found. Furthermore, more than 300 million barrels of oil, or about 4 percent of the nation's oil consumption, is used to produce wasted food—and that figure doesn't even include the costs for processing and transporting food.

Researchers calculated the food waste of the nation as a whole over the last three decades, and then expressed the food waste on a per-capita basis to come up with the calculation that every person wastes about 1,400 calories of food per day. To arrive at that number, researchers found how much food was eaten by the population over the past several decades (data that had been compiled to explain the observed increase of body weight corresponding to increasing prevalence of obesity), then subtracted the amount of food eaten from the food available in the national food supply, and adjusted for imports and exports. This difference between the available food supply and the food eaten was defined as food waste. The numbers correspond with a 50 percent increase in food waste since the mid-1970s.

The study does have limitation, however. "The waste could have occurred at any point along the food supply chain, and our methods give us no information about where the waste is occurring," explains Hall. "Much of it could be due to household food waste, but waste also occurs in restaurants, supermarkets, food-processing facilities, and farms," explains Hall.

Individuals probably aren't to blame for all of the food waste. But it's a safe bet that even as obesity rates continue to climb, so does the amount of food we throw out—probably because it's a consequence of the easy availability of calorie-dense food that makes us fat. The pattern of doubling food waste during the last three decades is bad news for the environment as well as our waistlines. "We use so many resources to grow food. Shipping, tractors, and [chemical] farming practices are pretty damaging to the earth in terms of emissions and petroleum usage," Bloom says. "If we're going to do all that, we might as well eat the food. It makes no sense to grow twice the amount of calories we need and then throw out what we don't need."

While this waste occurs in all parts of the food chain, there is a lot you can do on the consumer end. And the best part? It'll help save you money, too.