Wednesday, October 16, 2013

AHS13: A caveman's guide to world hunger.

In August, I had the privilege of speaking at the third annual Ancestral Health Symposium, which focused on an evolutionary approach to nutrition and health. The title of my talk, “Give them grains? Analyzing approached to world hunger”, was intentionally provocative as this group has pretty negative views of the role of grains in human nutrition. I wanted to get people’s attention because, quite often, the response I get from this community is that they care about making healthy choices for themselves, whether or not those choices are sustainable or widely accessible. While I understand this view, opting out of the conversation about our global food future means that we are less likely to develop a food system that meets the demands of health-conscious people. As it happens, I also care about the accessibility of food, especially for the poor. What follows is the content of my presentation at AHS13.   


According to the UN’s Food & Agriculture Organization, there are more than 850 million starving people in the world. Moreover, there are a staggering 2 billion malnourished people. In fact, malnutrition kills 2.6 million children each year, and 1 in 4 children experience irreversible stunted growth. Vitamin A deficiency alone affects 250 million preschool-aged children; many become blind as a result, and half of the children who become blind die within a year.

Clearly, when we think about how to feed the world, we need to be considering the nutritional value of food as well as its caloric yield. Calories may keep a starving person alive for a day or a week, but to have someone survive for months, years, or decades, nutrition is key.

The most common proposed solution to world hunger is based on the premise that we can use grains to increase the total number of available calories, worldwide. We can do this by growing more grains, increasing grain productivity, and eating more of the grains we currently grow rather than using them for animal feed or fuel. This last point is especially relevant for industrial corn. Several studies have analyzed precisely how many more calories could be consumed if they were eaten “directly” rather than eating animals fed with corn.

To really determine whether eating more corn can help feed the world, we need to consider the type of food produced in this system and the trade-offs between corn and other crops.
In 2011, the US harvested 83 million acres of industrial corn, which does not include sweet corn that you would eat on the cob or out of a can. The same amount of land comprises the entire National Parks system. According to the USDA, 52% of the 2011 corn crop was used for fuel and exports, thereby contributing zero calories to the US food supply. Another 37% of the corn was used as animal feed, leaving only 11% of the crop for food. It seems pretty clear that using more corn for food would produce more calories, but how much more? 
The above chart shows my estimate of the caloric yield of the corn crop based on the current usage distribution. If 37% of the corn crop was eaten indirectly through corn-fed animals and 11% was eaten directly as “food”, I estimate a yield of 1.8 million calories from the 2011 corn harvest. If, however, we had eaten the animal feed ourselves (for a total of 48% in the food category), it could have delivered 2.5 million calories. And, if the entire crop were used for food, it would yield 5.3 million calories. That means we could just about triple the number of corn calories in the food system simply by devoting it all to food. Let’s take this one step further, though. What kind of food do we actually produce from industrial corn?
Before humans can consume industrial corn, it has to be heavily processed. Again, based on USDA statistics, the 2011 corn calories were delivered in the form of high fructose corn syrup, glucose and dextrose, corn starch, alcohol, and corn oil (which makes up the majority of the "Cereals, other" category). Despite the calories, no one can survive on a diet made of these foods. More importantly, consuming calories in these forms does little to reduce the total number of calories a person needs. For example, studies have shown that drinking a soda, which delivers a few hundred calories, will not cause someone to eat fewer calories throughout the day. That means, regardless of how many additional corn syrup calories we can deliver to the food system, we will still need to produce the same number of calories from other foods to meet everyone’s caloric needs. To borrow a term from economics, corn-based calories have diminishing marginal utility.

But let’s forget about calories for a moment. Given that billions of people in the world are malnourished, what are the relative amount of micronutrients that corn would deliver in each of these systems? I chose two micronutrients, vitamin A and folate, for this analysis because deficiencies are known to cause serious, life-threatening health problems.
It turns out that the best source of corn-based micronutrients (based on efficiency and content) actually comes from chicken liver. A back-of-the-envelope calculation reveals that, based on our current corn usage, an acre of industrial corn could provide 141 people with their recommended daily amount of vitamin A and 66 people their RDA of folate through the consumption of corn-fed chicken livers. On the other hand, if we stopped feeding corn to animals, and used it instead to make corn syrup, corn oil, and the like, we would produce zero RDAs of these micronutrients. Finally, if we used all of our corn in such a way as to maximize vitamin A and folate production, we would feed all of our corn to chickens, which would enable us to feed 385 people their RDA of vitamin A and 180 people their RDA of folate with one acre of corn.
Eating our corn directly would provide an increase in available calories, but it would also reduce the already minimal micronutrients delivered by corn. The standard American diet is already rich in the types of food that corn can produce. As a nation, we already generate 3770 calories per person per day, and 70% of the average American’s calories come from refined grain, added sugar, and refined vegetable oil. We also have a nation of very sick people. Over 35% of adults are obese, more than 23 million have Type 2 diabetes, and another 79 million have pre-diabetes. Is this really the diet we want to use to end world hunger?
Given that corn is such an abysmal source of vital micronutrients, it’s worth asking if there is anything better we could grow. Organic produce is more sustainable than conventional agriculture and typically more diverse. The USDA’s organic production survey compiled statistics for the 22 highest yielding fruits and vegetables, which were grow on a tiny 118,000 acres – that’s 0.14% of the land devoted to industrial corn.
Using nutrition data from self.nutritiondata.com, I calculated that the 22 highest yielding organic crops generated 3 million calories per acre. That’s more than corn delivers even if we stopped feeding corn to animals but less than if we devoted the entire crop to food. Nutritionally, however, the organic crops clearly dominate.
To simplify the calculations, I selected two organic crops and used the USDA data to determine the per acre yield of each one. I then calculated the RDAs of both vitamin A and folate. If we grew an acre of organic carrots, we could deliver ¾ of a million people their RDA of vitamin A and more than 1600 people their RDA of folate. From an acre of organic spinach, we would supply almost 61,000 people their RDA of vitamin A and 14,000 people their RDA of folate. 
To summarize, we could produce more calories by eating more corn products, but it would reduce the amount of available micronutrients and not do much to reduce the caloric needs of our population. Sustaining a healthy population is even more problematic as corn provides either micronutrients or calories, but not both. Corn agriculture also requires a great deal of inputs with many negative outputs. In contrast, organic agriculture can provide about 50% of the maximum caloric yield of corn, while also providing prodigious micronutrients. In marginal environments, which are more common in the developing world, organic agriculture can actually produce more calories than conventional, input-intensive agriculture. However, developing truly sustainable agricultural systems, worldwide, will require dedication, creativity, and investments in research and labor.
Overall, growing nutritious crops will likely produce fewer calories. However, globally, we already grow more than 2700 calories per person per day. Even in the countries with the highest rates of hunger, only two actually have too few calories available, and even those are within 100 calories of their daily per capita needs. Chronic hunger and malnutrition are caused by poverty, political instability, and lack of infrastructure. Simply producing more calories, in any form, is unlikely to end world hunger if issues of access are not addressed. Hence, the lower caloric yield of organic crops seems worth the trade-off given their delivery of vital micronutrients, promising yields in places where the poor actually live, and the potential for sustainability.
I think I have made the case that eating more corn products, rather than eating corn-fed animals, is not a good solution to world hunger. In fact, eating corn-fed animal products is the only way to get micronutrients from corn. However, I do not, in any way, support feeding corn to ruminants or raising animals in confinement. Rather, I think we should stop growing industrial corn and go back to raising animals in traditional pasture-based systems. This would likely reduce the amount of meat available in the food system, although I have yet to see a detailed study of the potential yields of polyculture, pasture-based farming systems. Regardless, limiting our consumption of animal products to the level that can be produced sustainably seems like the right approach. 
Overall, this analysis has revealed the importance of considering nutrition, in addition to caloric yield, when making decisions about what we should grow and eat. This above slide lists several ways we can support real solutions to world hunger and organizations who appear, to me, to be taking the right approach. Whether you base your eating habits on what is healthy for you or healthy for the world, I encourage you to get involved and make the food system work for everyone.

I want to thank Eric Huff and Tess McEnulty for their assistance with this project and the Ancestral Health Society for creating a forum for this type of work. Additional citations and background for the calculation of the caloric yield of corn can be found in my previous post. Supporting materials for the hunger assessment by country and specific inputs and outputs of the conventional food system can be found in my 2012 AHS talk, which is described in detail here.

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