It's well known that some foods take more energy, land, or resources to produce than others. Unfortunately, there are many myths about sustainable crops, and fewer discussions based on statistics. Perhaps the most pervasive myth about sustainable food is that no animal foods are sustainable, so to save the planet all humans have to eat a vegan diet based on grains and legumes. (I do not agree, and will explain why in the body of this post.)
On the other side we have Robb Wolf, who in his post on the subject questioned the existence of global warming and the need to live a sustainable lifestyle. He dodged the issue of whether we have enough resources to supply everyone in the world with a pound of grass-fed steak a day without destroying the planet, preferring to dwell instead on the fact that sweet potatoes, corn, and cassava have higher yields per area of land than grains like wheat and rice. This is indeed true, but it misses the point, because Robb Wolf does not actually support the consumption of sweet potatoes, corn, cassava, or other starches.
Other Paleo or ancestral health websites recommend local vegetable gardens and pastured animal products, which is an important start, but may not be enough to save our planet.
It behooves us to find a middle path and examine the actual evidence. To this end, I am in the process of writing a series of posts on the subject. This one is about the highest yield calorie sources:
On the other side we have Robb Wolf, who in his post on the subject questioned the existence of global warming and the need to live a sustainable lifestyle. He dodged the issue of whether we have enough resources to supply everyone in the world with a pound of grass-fed steak a day without destroying the planet, preferring to dwell instead on the fact that sweet potatoes, corn, and cassava have higher yields per area of land than grains like wheat and rice. This is indeed true, but it misses the point, because Robb Wolf does not actually support the consumption of sweet potatoes, corn, cassava, or other starches.
Other Paleo or ancestral health websites recommend local vegetable gardens and pastured animal products, which is an important start, but may not be enough to save our planet.
It behooves us to find a middle path and examine the actual evidence. To this end, I am in the process of writing a series of posts on the subject. This one is about the highest yield calorie sources:
Starches Corn White potatoes Sweet potatoes Yams Taro Cassava Squash Rice Wheat Sorghum Oilseeds Palm oil Almonds Peanuts Hazelnuts Copra (dried coconut meat) Sunflower seeds Sesame seeds Flaxseeds Pumpkin/squash seeds | Calories/100 sq ft 30,000 27,500 21,000 16,500 (1) 15,500 (2) 15,000 (3) 10,000 9,800 (4) 9,000 6,400 (5) -- 37,500 (6) 18,400 18,000 (7) 17,100 15,300 (9) 9,300 7,800 3,100 2,000 |
Obviously, the above is a gross oversimplification. It does not take into account the type of soil, amount of water, amount of fertilizer, and so on needed for the above yields. However, it does cast serious doubt on the notion that a high-grain diet is the most sustainable option. I would also like to note that white potatoes and cassava are known for their hardiness and ability to thrive on marginal environments, and that tuber crops are much easier to grow on rocky soil than grain crops. Sweet potatoes, cassava, and taro all have edible leaves which could serve as micronutrient sources, and squash seeds not reserved for the next planting could provide some nutrition as well. The coconut tree also produces coir fibers, which make excellent fertilizer.
It's interesting that the most efficient foods to grow are not necessarily the cheapest. In particular, tubers, almonds, and hazelnuts are more expensive than one would expect, and wheat and rice cheaper. There are a few possible reasons for this: 1) higher labor costs due to less automation of non-grain crops; 2) economies of scale for grain crops, due to high consumption; and 3) greater difficulty in transportation and storage for non-grain crops. I am not familiar enough with agriculture to say which is driving the price differentials.
The next post will discuss the most efficient protein and micronutrient sources.
It's interesting that the most efficient foods to grow are not necessarily the cheapest. In particular, tubers, almonds, and hazelnuts are more expensive than one would expect, and wheat and rice cheaper. There are a few possible reasons for this: 1) higher labor costs due to less automation of non-grain crops; 2) economies of scale for grain crops, due to high consumption; and 3) greater difficulty in transportation and storage for non-grain crops. I am not familiar enough with agriculture to say which is driving the price differentials.
The next post will discuss the most efficient protein and micronutrient sources.
(1) I assume a yield of 15 tonnes/ha and 1.18 cal/g.
(2) I assume a yield of 15 tonnes/ha and 506 cal/lb.
(3) I assume a yield of 10.2 tonnes/ha and 726 cal/lb. This is the average African yield and would probably be higher with Western farming methods.
(4) Dry yield 3 tonnes/ha and 1600 cal/lb. I'm not sure if this figure takes into account multiple harvests. (In many regions, two or three harvests of rice per year are common.)
(5) Yield 80 bu/acre; 56 bu/lb; 3.39 cal/lb dry.
(6) Oil yield of 4.5 tonnes/ha, mostly palm oil with some palm kernel oil; at 9.0 cal/g. If the fruit were eaten, the calorie yield would probably be higher because oil presses do not extract all the calories from the fruit. However, defatted palm fruit could be used as animal feed.
All starchy foods not explicitly cited above refer to source (7).
All oilseeds except peanuts and coconut are from source (8). All of these figures are for whole nuts, not oil.
(9) Assuming calorie density of 6.6cal/g and yield of 2.5 tonnes/ha.
(2) I assume a yield of 15 tonnes/ha and 506 cal/lb.
(3) I assume a yield of 10.2 tonnes/ha and 726 cal/lb. This is the average African yield and would probably be higher with Western farming methods.
(4) Dry yield 3 tonnes/ha and 1600 cal/lb. I'm not sure if this figure takes into account multiple harvests. (In many regions, two or three harvests of rice per year are common.)
(5) Yield 80 bu/acre; 56 bu/lb; 3.39 cal/lb dry.
(6) Oil yield of 4.5 tonnes/ha, mostly palm oil with some palm kernel oil; at 9.0 cal/g. If the fruit were eaten, the calorie yield would probably be higher because oil presses do not extract all the calories from the fruit. However, defatted palm fruit could be used as animal feed.
All starchy foods not explicitly cited above refer to source (7).
All oilseeds except peanuts and coconut are from source (8). All of these figures are for whole nuts, not oil.
(9) Assuming calorie density of 6.6cal/g and yield of 2.5 tonnes/ha.