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:
Copra (dried coconut meat)
Calories/100 sq ft
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.
(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.