Wednesday, March 7, 2012

Wasted. (Part II)

Extra body weight becomes a problem any time energy intake is greater than energy expenditure. We know that Americans eat out more (see Because My Baby Likes It) and move less, and we have a wider variety and quantity of snack products available than ever before.  Besides a reduction of exercise (energy expenditure), can we blame a large portion of America’s weight problem on an increase of energy intake driven by overabundant energy production? In other words, are we producing too much food in this country, and an empty plate is the only STOP sign we give ourselves? We will discuss the findings of studies about Eating Wastefully, Producing Wastefully, and Consuming Wastefully.

Eating Wastefully
Body weights have increased from the 1970s to the 2000s (Swinburn et al., Estimating the changes in ‘energy flux’ which characterizethe rise in obesity prevalence. Am J Clin Nutr 2009). Likewise, per capita US food supply has increased, even when corrected for food waste (USDA ERS). Energy intake increased in adults from 2398 calories per day to 2895 / d from ‘70s to the ‘00s (+500 calories). Energy intake increased about 350 more calories in children from 1690 to 2043 per day.

Known: Increased per capita food supply and increased body weights have followed similar trends from the 1970s to the 2000s.

Unknown: Direct correlation between increased per capita food supply and increased body weights.

For now, the choices seem to be 1) turn down extra helpings of food to see them get thrown out, or 2) waste extra food on your own body as extra weight. Please eat responsibly...and try to donate food you don't need. Google food donations in your hometown. Some organizations will even take uneaten perishable food that is still packaged.

Producing Wastefully
U.S. food waste was quantified by Hall et al., 2009 as being 1400 calories per person, having increased 50% since 1974. This food waste represents the waste of ¼ of our freshwater usage and about 300 million barrels of oil (4% of total US oil use). Americans have wasted more food per capita over a 30 year progression, starting from 1974 when 900 calories per person were wasted.

Approximately 40% of the food produced in the U.S. gets wasted (up from 30% in 1974). However, the percentage of available food wasted per capita has been the same (about 30%). For some reason, more food is rotting and spoiling today per capita than in the 70s. Of whatever is left over, that percentage of waste has not changed…i.e., 30% of perfectly good food has continued to get thrown out from the 70s to the 00s.
Thirty (30) percent of food waste can be found in the trash and in landfills (EPA data), most likely meaning that about 30% of total food waste is because of consumers and retailers (grocery store waste, restaurant waste, home waste, etc.). There has been a 50% increase of total landfill food waste per capita since the 70s. Perhaps this means that a shift in wastage culprits has occurred since the 70s, being towards consumers and away from production and distribution. By the way, the USDA acknowledges that this estimate of consumer waste is an underestimate, since this has been particularly difficult to quantify.
Composting is a great way to conserve nitrogen (somewhat, remember from Determined To Succeed that it's elusive), minerals, organic matter, and landfill space. However, it is not an efficient way to recapture the energy that food contains, since much of it ferments into methane as it rots (if not well aerated), a greenhouse gas 25x more potent than CO2.
The paper makes the suggestion that increased food availability and continued waste (in America, there’s been more than enough to go around from the 70s until now) means that the oversupply of food still can’t be matched by our intake. We simply can’t eat more, and because of our weight problem, we shouldn’t eat more, we should be eating less. If we ate less (the right amount), there’d be even more food waste. So…why not address the food waste issue? 

Consuming Wastefully
A UK study performed by Parfitt et al., 2010 summarized production food losses as primarily occurring from a lack of thorough harvesting (crops left in the field), pest damage, crop damages during harvesting, spillage, rot, and contamination. Industrialized countries are less likely than developing countries to lose food in this way. Furthermore, byproducts of food processing are swiftly utilized for animal feed (i.e., cottonseed meal, soybean meal, distiller’s grains from ethanol…etc.)  
Consumption food losses mainly happen by products spoiling (not being bought or consumed in time), plate scrapings (not finishing a meal), or poor food preparation techniques (too much edible vegetable or animal parts are thrown away). This is typical of industrialized countries more than developing countries. 

What I found to be very, very surprising is that, in the UK, the vast majority of food waste was not in manufacturing, not in distribution and retail, but in HOUSEHOLDS, followed by half as much waste occurring in the hospitality sector (restaurants, hospitals, hotels, etc.). 

While this is shocking to me, it makes sense for a restaurant to maximize their food resources to turn a profit. The average household cook, however, won’t always continue eating a whole turkey or chicken if the breast is finished. The average person eating homemade meals doesn’t want leftovers more than once. Frankly, leftover fish can just be nasty. Fresh vegetables and salads don’t stay fresh for long (and they make up the majority of throwaways, over drinks, fruit, breads, meat, and dairy/eggs, in that order). You’d think that with refrigerators in every home, we’d have a lot less waste, but we might have a lot more complacency and food taken for granted instead. When visiting China, I found out that the majority of Chinese people don’t have refrigerators, and they visit the markets every morning to buy exactly what they need for just the day. Also interesting, single-person households throw away more than larger households, which makes sense since it’s hard to cook for one unless you can love, love, love leftovers. The two most common reasons for food wastage in households were “food not used in time” and “too much food is served”.

Here’s what the Parfitt study suggests:

1)      Take a home food inventory and make a shopping list before going to the store. Refrigerators crammed with food become cold trash cans!
2)      Don’t impulse-buy, stick to the list.
3)      Read the food labels. ‘Sell by’ does not mean ‘Best before’ which does not mean ‘Use By’.
4)      Plan meals.
5)      Recombine leftovers into new meals. 

Don’t take food for granted. Right now, we may be producing a little more than enough total calories for everyone, but after 40 more years and 2 billion more people, expect that to change. 

Since the main culprit is on the consumption end, how do you Think we can reduce food waste?

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