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Forego a Hamburger, Feed a Person

Posted by Andrew McGuire | September 5, 2013
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I eat meat. More specifically, I eat feedlot beef from major supermarket chains and generally enjoy it. Nonetheless, the implications of a recent study have me questioning whether I will eat meat in the future.

In their paper, Redefining agricultural yields: from tonnes to people nourished per hectare, Cassidy et al. present the case that we could feed an additional 4 billion people by growing food for people rather than for livestock. We could do this because feeding crops to livestock is inherently an inefficient way to feed people. In the U.S. (worst case country in this paper), only 1/3 of the calories produced per acre (pre-waste) actually make it to people, mainly due to corn being grown on a large amount of land but being fed to livestock, where most of the calories are lost. The authors estimate that “The US agricultural system alone could feed 1 billion additional people by shifting crop calories to direct human consumption.”

4 billion people! 1 billion from U.S. agriculture alone. Those are numbers that matter. Many experts think we will have 9 billion people to feed by 2050 and many recent conferences, meetings, and efforts are focused on just how to do this. Biotechnology? Increased fertilizer and other inputs? Increased irrigation? Experts say that these will be required to make up the yield gap between current yields and the best-observed yields. However, despite the talk of sustainable intensification, at least some of these strategies, as currently practiced, have negative effects on the environment. And if implemented fully, they would only raise yields by 45-70%, not the 70-100% increase we need to feed all 9 billion people.

Given this sizable problem, and all the money and thinking going towards solving it, I was astonished (although not surprised, I had seen the argument before) at the implications of the Cassidy paper. If we could feed 9 billion with our current land and yields, we would not have to spend lots of time and money trying to continually increase yields AND do it sustainably. We would not have to fully adopt every new technology available.  We could focus on addressing current sustainability problems. This would be a much easier task, especially when facing other large problems such as climate change and adjusting our economies to a stable population.

Is it as simple as saying “I will not eat meat so that others can live?” Perhaps for the individual, but it would require drastic changes in our cropping, farm program, and food distribution systems. We have a huge investment in breeding, production technologies, infrastructure, farm equipment, processing and transport systems, all focused on corn. Not to mention a large number of farmers who know how to raise corn well.

There are also cultural (Beef. It’s what’s for dinner), economic (can those who need food pay for it?) and political (food distribution; corn and ethanol subsidies) challenges to this solution. Ideally, meat would become increasingly expensive, people would reduce its consumption on their own, and farmers would have time to transition to different cropping systems. All this would require leadership to enact policy changes.

Are the numbers in this paper reasonable? I looked over the major assumptions (you can too, the paper is available to anyone) and did not see any glaring problems. Given that these kinds of global studies are always just estimates, I find comfort in the number 4 billion. If, as experts predict, we only need to feed another 2 billion (current population estimate is 7.1 billion), then we have 2 billion in slack. This could potentially make up for resistance to change in Western countries, or for China and other developing economies going on a meat-eating spree for a while.

What this paper points out is that there is a clear solution to the problem of feeding 9 billion people. Given the alternatives, I think this should be a major part of our strategy in feeding the world’s future population. I eat meat, but I would give it up to feed other people. Would you?



Emily S Cassidy, Paul C West, James S Gerber, Jonathan A Foley. Redefining agricultural yields: from tonnes to people nourished per hectare. Environmental Research Letters, 2013; 8 (3): 034015 DOI: 10.1088/1748-9326/8/3/034015

9 thoughts on "Forego a Hamburger, Feed a Person"

  1. Chuck Benbrook says:

    Very interesting paper. I have done some estimates of what I call “human nutrition units” per acre, based on crops grown, yields, and the percent of yield that reaches people. For each food, a nutritional quality score is calculated based on nutrient content per 100 grams or per serving, relative to nutritional needs. The basic metric for one nutrient is, e.g., grams Vitamin C divided by the RDA for Vitamin C. The shares of each of 26 nutrients, relative to daily needs of the nutrients, are added together in a composite score. On a daily basis, people need to consume food such that they get ~100% of each nutrient, relative to their needs. The differences across foods in terms of human nutrition units per acre are amazing. The unchallenged super-star food is sweet potatoes. Several popular fruits and veggies actually score relatively low because they are mostly water and don’t contain many nutrients. But by moving land from low-return uses, e.g. growing alfalfa hay to feed Andy’s beef cow in a feedlot, to high return uses like sweet potatoes, potatoes, carrots, tomatoes, etc, the world could feed many billions more people (likely more than the 4 billion number in this paper). But one huge caveat looms — the amount of ag land and associated resources that gets drawn into renewable fuels production. Shifting land from crops feeding cattle in feedlots to bioenergy is not going to help much in promoting food security.

  2. Tilimsa Yyrevaa says:

    Will you eat only sweet potatoes, potatoes, carrots, tomatoes, etc (whatever etc means in this case)every meal for your whole life? Articles like this sounds great, however unless the authors of the articles and the comments commit and follow thru with their recommendations, including not driving vehicles, etc,…

  3. Andy McGuire says:

    Chuck, a few clarifications about this paper. It did include calculations for crops raised for biofuels, but they were only 6% of global crop production vs. 24% for feed crops, so I focused on the feed crops.

    Regarding alfalfa hay, the paper did not include grass and forage crops because of the lack of available data. So it would be corn and/or soybeans going to the feed lot. Grass/forage-fed (including alfalfa hay) beef and dairy would potentially be guilt-free if the forage was raised on land not deemed suitable for producing people food.

    Finally, the paper focused on calories and protein, so fruits and veggies did not come into play as much as rice and wheat, as they provide us with the majority of our calories, although sweet potatoes did make one chart.

  4. Andy McGuire says:

    Tilimsa, you bring up a good point. We would have to add more than what Chuck mentioned to our diets, crops like beans, lentils, chickpeas and other grain legumes would become more important, especially to replace meat’s high quality protein. We would have to combine plant-based foods to get complete proteins. However, the paper pointed out that, overall, protein availability would double.

  5. Crystal says:

    While a valuable argument for reducing meat consumption, which I fully agree, I think we need to consider a few other factors before we banish animal products. There are millions of hectares of lands unsuitable for tillage crop production. Ruminants can utilize this land to produce food for humans maybe mostly milk as that is more efficient. But even with milk production, there are cull cows and calves to as a byproduct. Hogs and chickens could be great food recyclers. What if most homes had some chickens outside the back door to eat the nearly 50% of food that wasted in this country. They could convert it to eggs and then again we’d have some meat from roosters and cull hens, plus some great fertilizer for the home garden. We do likely need far less meat than we eat here in the U.S. but their is a valuable place for livestock in our ag systems we just need to reinvent what it looks like.

  6. Andy McGuire says:

    A bit more on livestock raised on grasslands instead of cropland. We cannot just shift meat production from cropland to grassland as recent research on the Mongolian Steppe shows.

    For this to work, we need to consume less meat.

  7. Lynne Carpenter-Boggs says:

    Well said Andy, and many other good points in the conversation here. As Andy said, the argument is not new but warrants repeating and detailing.

    Simon Fairlie wrote an outstanding book “Meat: A benign extravagance” on the subject of meat production and environmental impacts. It agrees with statements above from Andy, Chuck, and Crystal. Feeding high-quality food to animals, to make less high-quality food, is a losing venture calorically and environmentally. But using low-quality foods, food waste, and less productive lands (under good management) for livestock and their products is highly efficient and environmentally beneficial. Every spot on the earth simply is not the same and should not be used the same. In some places the most efficient production of “nutrition units” will be from animals.

    Besides, if no one ate chickens or eggs they probably wouldn’t exist. I believe my chickens are glad to exist.

  8. Joanne Cannon says:

    The problem on feeding the population has been a around for quite some time. Athough the numbers are not going well for us in projecting the future but we have always managed to survive and come up with a way to solve the current problems. I say that we cross the bridge when we get there. For sure there is always a way.

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