Ending World Hunger: Sources of Protein

What most people do not understand about world hunger is that most hungry persons have some food. A famine occurs when a population does not have enough food to survive. Hunger is chronic undernourishment, which includes populations with enough food to survive, but not enough total calories or macronutrients (protein, fat, and carbohydrates) for good health. According to the World Food Programme, situations “which starve a population of food … account for less than eight percent of hunger’s victims” [WFP: What Is Hunger?].

More specifically, most of the hungry of the world have sufficient or nearly sufficient carbohydrate intake, but they lack protein and dietary fat. This conclusion is based on data from the FAO World Hunger Report 2008 [Technical Annex, Table 2]. The majority of undernourished persons in the world have some staple food, such as rice or maize, for survival. Their staple food is high in carbs, with a modest amount of protein, but very little fat. So they need dietary fat and additional protein, much more than they need additional carbs.

In my book Hunger Math: world hunger by the numbers, I analyzed over 120 crops to find the most productive sources of each macronutrient: protein, fat, and carbohydrate. In other posts on this blog, I’ve discussed the need for dietary fat and the most productive fat crops. Here I’d like to deal with the issue of protein crops.

My analysis of protein crops includes common and uncommon grains, legumes, nuts, and seeds — all of which offer substantial amounts of protein. But I also considered non-traditional protein crops, such as root and leaf vegetables. Some of these crops have only a modest amount of protein, as a percent of total food weight. But they offer high yields, on a per month per hectare basis, resulting in a high total production of protein. If the protein were extracted from these crops as protein concentrate (PC), they might be competitive with traditional protein crops for the amount of protein produced per crop or per year.

The surprise result of this analysis was that the top 15 most productive sources of protein (normalized to a per hectare per year basis) includes 11 PC (protein concentrate) crops and 2 traditional protein crops (soybeans, peas). Pumpkin with hulless seeds is a productive source of protein only if PC from the flesh is added to the protein in the hulless seeds. Duckweed (also called water lentils) is on the list twice, at both high and low estimated yields. Even at low yields, water lentils are one of the most productive sources of protein.

So 80% of the top crops for production of protein (12/15 including pumpkin) are PC crops. Here is the chart of protein crops in PDF and image formats:

Image format (.png)
Adobe Acrobat format (.pdf)

Duckweed (water lentils), at a high estimate of yield (30 t/ha), far out produces other crops for kg of protein per hectare per year. At a low estimate of yield (10 t/ha), the crop still makes the top ten list of most productive protein crops. The yields listed as high and low are on a dry matter basis (DM), i.e. calculated after neglecting the weight of water content.


The U.N.’s Food and Agricultural Organization (FAO) cites a paper from the Centre for Duckweed Research & Development at a University in Australia: “When effectively managed in this way duckweeds yield 10-30 ton DM/ha/year containing up to 43% crude protein, 5% lipids and a highly digestible dry matter.” [Duckweed – a potential high-protein feed resource for domestic animals and fish; Leng et al.]

Mushroom PC comes it at number two on the list of top protein crops, based on the typical high yields in the U.S. However, these high yields require much manual labor, and the land area used for production is indoors, adding to the expense. Also, mushrooms have an essential amino acid profile that is far from ideal [Mushrooms essential amino acids]. As a result, PC from mushrooms is not practical.

Broccoli Raab has a good essential amino acid profile and is a productive crop. It’s yearly productivity is mainly due to its short season: 2.5 months from planting to harvest. If it were used as a PC crops, it would be productive. But broccoli raab may have anti-nutritional factors that make it less than ideal for large-scale use. A similar analysis applies to green tomato. A short 2.5 month season results in a high productivity. However, green tomato has a less than desirable essential amino acid profile.

Several other crops might be good candidates for production of protein concentrate (PC). But this approach to agriculture and food production is relatively new, and my analysis is largely theoretical. Particular crops might be more difficult to use for PC due to anti-nutritional factors, difficulty in processing the crop, or a requirement for excess manual labor. Right now, duckweed (water lentils) is the most promising PC crop.


Recently, I came across a fairly new company, Parabel USA Inc., whose research and products are based on a particular variety of duckweed called Lemnoideae. They call the crop “water lentils”, a common term for duckweed since at least the early 1800’s [according to this Google books search].

Currently, they have two food products, LENTEIN, which is a protein concentrate, and Water Lentil Flour, which has less protein than the concentrate, but more fiber and other nutrients. The flour is 16 to 20% protein, with an excellent essential amino acid profile. It is a complete protein. The LENTEIN protein concentrate is 65 to 70% protein, with less fiber and other nutrients. LENTEIN is suitable for adding to commercial food products, such as chips or baked goods, to increase their protein content. Water lentil flour is suitable for use as a food ingredient for commercial or home cooking.

One strong advantage that water lentils have over other protein crops is the ability to recycle the water. Parabel states that “LENTEIN TM is produced in an aqua farm where 98% of the required water gets recycled and has been described as carbon neutral.” In many nations today, water has become a limiting factor in agriculture. Water in underground aquifers is being pumped out faster than nature can replace the water. A severe drought has struck California and surrounding States, as well as other regions of the world. The ability to recycle the water in an essentially closed system, when producing protein from water lentils meets a dire need in food production.


Without more protein, we cannot end world hunger. Animal source foods are high in protein, but they are inefficient in their use of agricultural resources. It takes too many hectares of land for the amount of protein those foods provide. And it is not practical to increase the arable land and agricultural resources to meet the world’s need for additional protein with inefficient crops. The continued growth in the world population has not been matched with a proportionate increase in arable land.

More research is needed into PC crops. The world is in dire need of protein. Currently, the most productive protein crop is soybeans at 3.2 tonnes of protein per ha per year, and just over 1 t/ha per crop. But most of the soy grown in the world is used for animal feed (along with maize). Duckweed PC has the potential to triple the protein yield of soybeans. Most of the other top crops for protein are also PC crops.


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