Whenever discussion is under way about how best to attain the large increase in global food production required in the next three or four decades to meet the needs of a growing population, almost as a footnote the belief is voiced that this problem may be most easily addressed if food waste and loss could be reduced. Sensitivity to this assertion is magnified by realizing that no one has any solid proof as to how much food actually is lost or wasted. Indeed, it is to the credit of the food manufacturing industry that its processes are no longer singled out as a focal point of waste. If any progress has been made in reducing these losses, the food industry belongs in the forefront. But the savings in processing or distribution, as compared to what occurred in earlier times, are insignificant in responding to this important, but too often neglected, aspect of measuring food availability.

At a recent conference in Stockholm dedicated to addressing the “looming global food crisis,” the head of the International Water Institute, which sponsored the event, declared that “up to half” of world food production is not eaten. Cited were two very different types of losses to underscore the differences between developed and developing nations. For example, in India, the claim was made that up to 40% of food production rots before it reaches markets. That contrasts with the United States, where it was asserted that Americans “bin” 40% of the food they buy to eat.

These horrific estimates exceed the loss estimates made by the Food and Agriculture Organization of the United Nations. The F.A.O. estimates that one-third of food produced for human consumption is lost or wasted. Defining that loss as 1.3 billion tonnes per year, the F.A.O. divides the total between post-harvest losses before the food even exits the farm gate and food wasted or lost along the food chain in developed nations. While acknowledging differences between nations depending on economies, the F.A.O. emphasizes that most food is wasted on a per capita basis in developed countries. It says that the average annual per capita waste in Europe and North America approaches 95 to 115 kilograms, while in Sub-Saharan Africa and South/Southeast Asia it is 6 to 11 kilograms.

One of the most intense efforts aimed at having accurate data is being pursued by the Economic Research Service of the U.S. Department of Agriculture. The basic goal is to know the amount of food — mainly calories and nutrients — actually consumed across a broad range of families. The resulting product, named the E.R.S. Loss-Adjusted Food Availability Data, has included studies of household food consumption by independent organizations. Food availability figures are adjusted, which means reduced, by estimated losses in both the home and marketing system. The three sectors initially studied are retail stores, food service establishments and the home. Losses have been estimated for more than 250 individual foods.

Several examples underscore what this research has found about food loss. In the case of all grain foods, annual per capita availability is placed at 194.8 pounds, which becomes 171.5 pounds at the consumer level and ends up being 134.1 pounds eaten. Converted to a daily basis, what is eaten is 7.532 servings of grain foods, 610 calories and 5.9 ounces. In the case of wheat flour alone, availability, which is often erroneously cited as per capita consumption, is 134.7 pounds. That becomes 118.5 pounds at the consumer level and ends up being 94.8 pounds consumed.

In presenting these numbers, indicating a loss and waste share near 30%, the E.R.S. urgently requests recommendations for refining figures that do have the appearance of exactitude. Yes, it is important to be able to assure the reliability of data that rank equally in their impact with production statistics. Yet, even without total accuracy, the data affirm that these losses are of huge importance.