Boverty was defined in the previous post as the human impact of too many bovines overwhelming the local biosphere’s ability to feed them … the bovines are usually cattle and more than a few African countries have boverty induced poverty. Their livestock is a millstone around their necks and helping to keep them poor.
Western aid organisations, particularly those run by BBQ obsessed Australians, seem dominated by people haven’t woken up to the simple fact that the foods they grew up on when the planet had half its present population haven’t been sustainable globally for a very long time. Even in Australia, with its vast landmass and small human population, the production of these foods has driven and continues to drive water shortages, environmental degradation and biodiversity loss. Advocacy of such foods in Africa will benefit few and damage prospects of long term food security.
As outlined in the Part I, many grasslands on the planet are not the product of natural forces, but were cleared by people and kept as grasslands for livestock grazing by annual or occasional conflagrations. This is global burning on a massive scale as shown in the NASA firemaps presented in Part I. The continent with the most deliberate human burning is Africa. Over 200 million hectares and 2 billion tonnes of dry matter are burned annually in deliberately lit fires. Almost all of these fires are set by livestock herders to stop grasslands becoming forests. By comparison, burning by shifting cultivators for crops covered an area about 10 percent of this size. A recent study in Nature gives an idea of what could happen if the burning stopped. The reforestation potential is massive.
Consider the above image from the Nature article. The vertically hatched area has an average rainfall over 780mm and would, according to Sankaran and the large number of other authors, revert to some kind of forest if given half a chance. Its status as savanna is anthropogenic and not a product of natural attributes like soil type and climate.
How long can such regrowth go on adding carbon in the form of forests? Most additional carbon would be added during the first 3 decades but forests can go on adding smaller amounts for centuries. It’s worth noting that fire is probably always a suppressor of biomass production. The frequent claim that fire helps regeneration, making it some kind of friend of biodiversity, can be true but is highly misleading. I intend to do a post on this sometime in the future. But despite some plants benefitting from fire, the general impact is to reduce biomass production. Measurements under 2 rainfall regimes and 4 soil types in Africa always recorded higher biomass production in areas not burned.
One way of measuring a country’s fire intensity is to consider the ratio of biomass burned to biomass appropriated. We saw in Part I that Australia burns about 40 percent of what it appropriates. This ratio is the same as in South East Asia, but much higher than the 1 percent of Western Europe.
Both burn ratios pale beside the staggering 150 percent of sub-Saharan Africa where far more is burned than is otherwise appropriated. This is a stunning number. Corey Bradshaw recently wrote a piece on his blog where he summarised a recent paper on Australia’s mammal extinction crisis. His bottom line summary was that we should “Stop burning the shit out of our forests“. In sub-Saharan Africa, they are burning 12 times more biomass from an area 6 times bigger than the 37 million hectares we burn each year. If we are doing as Corey says, then what are the Africans doing? And for what? They reap far less than they burn.
How will global warming compound or alleviate Africa’s problems? The most critical impacts will be changes in rainfall regimes.
A warmer world is a wetter world but it is the timing and distribution of water that matters more than the absolute amount. This is as true for Africa as anywhere else. Perhaps the Sahara will gain water in a changing climate and return to its rather wetter state of 5000 years ago. Perhaps rainfall will be less regular but more intense, leading to more topsoil erosion and magnifying cattle impacts.
In any event, regional predictions are rather less certain than global ones. The good news is that for a substantial part of the potential reafforestation region we identified earlier, the predictions are for increased rain. It could also be viewed as good news that the rainfall predictions for the Sahel … that transition band of Africa that runs along the bottom of the Sahara desert, are uncertain. Uncertainty being rather better than a certainty of drying!
Africa is about 4 times the size of Australia but has 260 million cattle compared to our 28 million. On average the cattle are smaller with an average carcase weight of 150kg compared to 250kg in Australia. By now you may have predicted what so astonished me and drove the preparation of this post. The areas doing so much of the burning are precisely the ones with the most cattle and the most chronically hungry people. For example, Ethiopia and Sudan have 43 million and 41 million cattle respectively. In Ethiopia 80 million people eat 11 million tonnes of food while those 43 million cattle and assorted other livestock graze 80 million tonnes and are fed a further 20 million tonnes as feed. All these figures are DM (dry matter) numbers. Sudan burns over 30 percent of its entire annual vegetation growth … and this is 30 percent averaged over the entire country. Consider what this means. Australia burns huge areas, but averaged over the entire country the burn rate is less than 5 percent.
Cattle don’t bring food security
Proving that cattle cause starvation is tough, but demonstrating that cattle don’t protect people from food insecurity is trivially easy. It’s in the numbers.
This plot of per capita cattle ratios and undernourishment proportions shows pretty clearly that livestock are not effective in protecting people from hunger. Compare the food security of Nigeria, famously the happiest country on the planet which feeds 154 million people, with an undernourishment rate of 8 percent with Ethiopia, Sudan, Chad and Botswana. The latter have some of the worst poverty and chronic undernourishment on the planet while swimming in cattle and burning the shit out of their country every year. All the countries to the right of the 0.3 cattle per capita vertical line have more cattle per head of human population than the US. Allowing for the difference in cattle size we should really shift this line to about the 0.5 point. So Niger, Chad, Sudan and such have more cattle than the famously obese hamburger munching US. But still they starve. Does it look like more cattle will fix anything?
Nigeria’s submission to the IPCC states “Much of the savanna is a by-product of centuries of devastation by man and fire“. The author has a clear understanding of the problem and it looks as if some pretty effective steps have been taken because Nigeria’s biomass burning level is now just a tenth of Sudan’s. If you look at a high resolution version of the fire map from Part I of this post, you can see that Nigeria’s fires are fewer than those in the rest of that burning band. Nigeria feeds a population half the size of the population of the US but has only 10 percent of the land. Nigeria isn’t quite self sufficient in food, importing about 5 million tonnes of cereals to supplement the 25 million tonnes of cereals and 85 million tonnes of root vegetables it produces annually.
Root vegetables are probably the most efficient food crop per hectare of any on the planet. During some of the BNC discussion of Part I of this post, the subject of Polyface farm came up. Michael Pollan and Tim Flannery have both written flatteringly about this US farm. It is, to their minds, organic eco-friendly livestock production at its best. I did an analysis of Flannery’s vision for Quarterly Essay and will post a version of it on BNC at some time, but let me digress briefly on the production figures from Polyface which so astonished Tim Flannery in Now or Never, his Quarterly Essay. Polyface produces an annual combined total of 45 tonnes of various meats, plus some eggs from 60 hectares. The figures are probably carcase figures, so will be somewhat higher than the amount actually consumed.
An average Australian potato farmer would get some 2160 tonnes from 60 hectares, and the global average cereal productivity is well over 2 tonnes per hectare with many countries getting 3 or more times this yield. Most rice growers would get 400 to 600 tonnes from 60 hectares. Grow almonds on 60 hectares and you would get double the amount of protein without the pain and suffering of slaughter days at Polyface or the subsequent bowel cancer cases due to the red meat. And just to forestall the usual claims from US readers about grass fed meat being healthy and that all the many meat health issues are really just a result of grain feeding, I need to point out that most locally consumed red meat in Australia is grass fed, but we are generally top of the global table in bowel cancer rates. The causal chain from red meat to bowel cancer is now pretty well nailed down and has nothing to do with what the animals eat.
But returning to Nigeria. The Nigerians know about root vegetables, so next time you watch those brilliant Nigerian track athletes, the ones with the huge shoulders, just think of them as children … the odds are that they grew up on yams and other root vegetables!
Animal products provide less than 3 percent of Nigeria’s food calories. That 3 percent of animal products will more than likely be largely appropriated by the wealthy, the overseas oil consultants, and the tourists. Make no mistake, Nigeria is a desperately poor country with many serious public health issues, but its food production successes are remarkable given its tiny land area, its massive population, its history of burning, and the dominance of ignorant meat centric dietary advice from all manner of international agencies.
Growing food in a basket(case)
Do a little googling and you will find plenty of news stories over the past few years about China (and others) investing in Africa to grow food. At home, China is losing land to desertification and running out of water. It has also developed a taste for beef and now has over 80 million cattle (plus 20 million buffaloes) to feed on top of its half a billion pigs. What is the cause of so much of its desertification? Grazing, of course, with sheep being as effective as cattle.
But why Africa? How do you produce food in Africa? This is the continent with the worst food insecurity on the planet. A New York Times article relates the astonishment of a botanist who was flabbergasted at Saudi plans to grow food in Africa, thinking that if Africa can’t feed itself, how can it feed foreign markets? Easy. With some exceptions the problems of food in Africa are cultural and financial, they are not technical. Africa is 3 times bigger than China with 300 million less people. Yes, it has some rather large desert regions (40 percentof the land area), and some poor soils, but also large areas of current and potential forest. In simple terms, if mother nature can produce a forest somewhere then a good farmer can grow food.
More rigorous study of African soils, carried out a decade ago by the US Department of Agriculture, estimated that the 11 percent of Africa with good soils could support a doubling of the population while noting the desperate risks of rampant desertification due to low input agriculture and rapidly increasing livestock populations.
Foreign investors are demonstrating this in many countries in Africa. The Guinea Savannah mentioned in the NYT article above matches the vertically hatched area of the Nature paper quite well. This is land that can grow vast amounts of food but is currently set on fire in a massive cattle conflagration each year that produces nothing but ongoing boverty.
To be specific, Ethiopia, for example, claims (see above IPCC submission) about 73 million hectares of land suitable for farming but is using just 7 million. It has 3.7 million hectares suitable for irrigation and with adequate river water resources but has only 160,000 under irrigation.
Africa’s undernutrition problem, put simply, is that more than a few countries have a culture which prefers cattle and burning the shit out of the country to growing food.
Aid agencies … anyone for desert(ification)?
What is the role of aid agencies? Before proceeding, let me say that for many years I’ve been, and will continue to be, a regular donor to Oxfam. But the criticisms in this post must be addressed. Supporting disfunctional food cultures and policies isn’t aid, it is, at best, assisted suicide.
Part of the problem in dealing with Australian aid agencies is nutritional ignorance fanned by decades of meat industry lies couple with a deeply ingrained Australian BBQ culture. The irony of seeing the McGrath Foundation promoting the biggest source of bowel cancer in Australia, red meat, with BBQs outside supermarkets to raise funds to assist breast cancer victims is probably not uniquely Australian, but does illustrate the extent of the problem. Belief in the superiority of meat as the only real source of all the nutrients which matter is a myth that runs deeper in the Australian psyche than the Pope’s belief in God.
To illustrate, here is a 2010 ad from the Australia Day Council. It couldn’t have been more blatantly an ad for Meat and Livestock Australia if the latter had commissioned it from their ad agency. Note in particular the three meats: steak, sausages and lamb chops. There is no chicken … MLA is locked in a mortal battle with the chicken industry. Either I’m right about the ingrained nature of BBQ myths in Australia, particular among the those in positions of cultural influence, or there is serious corruption at the Australia Day Council.
But the king in the international spread of Boverty is not Australian, it is a US based group, Heifer International. This group runs, among other things, irrigated dairy projects in Ethiopia. A dairy industry, especially an irrigated dairy industry, is a brilliant way to fritter away scarce water resources and create a water crisis. New Scientist journalist Fred Pearce, in his book When the rivers run dry, wrote about the dairy driven plight of Gujarat in India. Pearce sketches the Gujarat irrigation treadmill nightmare as wells are driven ever deeper into a dropping water table to flood irrigate fodder fields for cattle. Again, the farmers involved may well profit, it is future food security that is being traded away. Where irrigation is river, rather than groundwater based, it is the opportunity for more productive use of water which is lost.
First world countries are not immune from dairy’s water hungry ways. In Australia, the dairy industry has been the biggest culprit in the over-allocation of Murray Darling Basin water. It is far and away the biggest user of irrigation water in Australia. At its peak in 2000/1 it dominated water use in the Murray Darling Basin using more than double the water of rice and 9 times more than fruit and vegetables combined. For all that water, the dairy industry in 2000/1 produced just 20 percent more calories than rice … with many of those calories being saturated fat which, in the developed world, is removed before sale … because it kills people. Some may argue that this is not an issue in parts of the world where diseases of poverty kill people before they get heart disease, but this isn’t accurate. The toll of ischemic heart disease is often high in developing countries. For example, the disability adjusted life years (DALY) lost rate due to heart disease in Sudan is four time higher than in Australia. Sudan can’t do the 40,000 major heart operations that Australia does annually to subsidise our livestock and junk food industries.
The revenue per million litres of that Murray Darling Basin dairy water was about 1/9 of that of water used to grow fruit, but with so much water being funnelled through the paddocks, it was still profitable … until the inevitable drought spoiled the party. Similarly, those Ethiopians involved in irrigated dairy production may be well be making good money, but regardless of the financial success of livestock aid projects in Africa, the long term impact of anything which serves to increase in the ratio of livestock to human biomass can only be to decrease food security for both humans and wildlife.
Of course it is true that understanding the root causes of a problem does not automatically provide solutions. Mapping realistic pathways to change a culture is tough and western countries have shown their own inadequacies in this regard by their inability to tackle the much simpler problem of obesity. We have been incapable of taking strong action against ingrained false and dysfunctional beliefs and against organisations who are perfectly happy to make people fat and unhealthy for a living (e.g., Hungry Jacks).
So let’s look at how Oxfam, Heifer International, World Vision, and other agencies who run livestock projects, directly contribute to African poverty.
Turning soil into dirt
Cattle without careful management are wonderful degraders of land. Their huge bulk pressing through small hard hooves compacts soil and kills much of what doesn’t go in their mouths. Consider the following grazing practices from an area of Kenya. They are no doubt replicated in villages across Africa and elsewhere. The idiocies should be obvious, but go unremarked by the author writing for the International Food Policy Research Institute (IFPRI).
None of the cattle owners in the study had enough land to meet the grazing requirements of their cattle, but local custom allows them to graze on anybody’s crop residues … without permission.
Residue grazing has many impacts.
It removes nutrients in the residues and uncovers the soil which maximises the further loss of topsoil and nutrients to wind and rain while the trampling ruins the soil structure. Yes indeed, soil has a structure and the physical structure effects everything from water flow and erosion rates to how nutrients find their way into roots.
The best you can hope for is that some of the nutrients may be returned as fertiliser. The key word here is some and may. Cattle dung from residue grazing can’t add nutrients to the soil that weren’t already in the residue and where dung is removed for fuel, the loss of nutrients is large.
All but the best and deepest soils will soon degrade under the abuse of being trampled and uncovered. Livestock advocates frequently write as if grazing crop residues was doing the world a favour … cleaning up the unsightly mess and turning waste into protein (see digression on protein). But these grazing practices are effectively trading the long term food security of good soil management for a little milk and an even tinier amount of meat. Nigerian studies compared leaving residues in place with removal and showed that residue removal halved crop yields over a period of 13 years and had a range of bad impacts on soil parameters.
It is taking farmers everywhere, not just in the developing world, quite some time to realise that bare fields are a recipe for long term agricultural decline, with ploughed bare fields being even worse.
Continuing with the Kenya grazing practices, … and again, the same will be true in many places. When cattle are grazing in and around crops and fences are largely non-existent, cattle need to be shepherded to stop them eating and trampling crops, this requires people power. An alternative control method when labour is short is to tether the cattle. This is perfect for concentrating and maximising the damage from cattle.
The low productivity of the soils was mentioned by the IFPRI author without apparently realising that she had described many of the processes that had produced that low productivity. The productivity of soils isn’t a given, it is a product of many things with more than a few being under our influence.
But cattle aren’t perfect. They will browse bushes but are more naturally grazers. If you want perfection in land degradation, you need to add an animal who can clean up any young shrubs and trees which the cattle hooves miss. You don’t want any vegetation to impede the winds in their efforts to blow away your topsoil. Goats are pretty well perfect for the job. The dynamic duo of cattle and goats will maximise the area left bare so that the wind and rain can strip topsoil to uncropped areas. Better still, if you have a local stream or river, the drifting soil from ground left bare by goats and cattle can silt it up for you. This is an added bonus in the raft of eco-system disservices provided by livestock.
Goat feeding for beginners
Goats are remarkable creatures, but frequently misunderstood. Their role as Oxfam gifts singles them out for particular attention. The capacity of goats to survive in harsh environments is achieved by pretty much the opposite of what most people believe. Goats don’t have low nutrient needs which can be met by any old plant matter. Assuming that you want a goat for milk and not just companionship and decoration, the standard veterinary advice on the minimal protein intake required for a 50 kilogram milk producing goat is 174 grams of protein per day. That’s enough protein to feed about 220 kilograms worth of people.
Goats survive in harsh landscapes not by having low nutritional requirements, but by an astonishing ability to fastidiously select and process the optimal available food for their needs. They will pick the newest leaves, shoots, twigs, stems, flowers or grasses, the ones with peak digestability and protein content. Where a sheep will make suboptimal choices when times are tough, the goat will find the best food.
To get the required feed to enable lactation, assuming you aren’t buying any feed, that 50 kilogram milking goat needs to eat about 2 kilograms of dry matter per day. This is the average NPP (remember NPP from Part I? Net Primary Productivity, a fancy word for plant growth) of 5 square meters of Africa over an entire year. This means a single milking goat will consume the entire plant growth of 1825 square meters of land during a year. But goats have no interest in NPP maximisation. Confine a goat to exactly 1825 square meters (about 2 empty suburban blocks) and you won’t find it in the same state at the end of the year, with the goat having nicely harvested the annual growth. No. A goat won’t feed to maximise the area’s productivity, it will start with the new growing shoots, stems and leaves. This depresses NPP. In a sense, the goat will gradually eat its way down the food quality chain and a dust bowl will be the result.
African goat breeds will have parameters somewhat different from those I’ve cited, and averages must always be taken for what they are, but the picture is clear. If you want to establish a belt of trees to shelter your fields and possibly for harvest when mature, then a free roaming goat is your worst nightmare.
Many aid agencies offer donors the chance to donate animals to a poor African family and goats feature prominently. Oxfam and World Vision are just examples. There are now some 290 million goats in Africa along with a similar number of sheep. To the extent that aid agencies encourage livestock acquisition, they are damaging long term prospects for food security.
Miscellaneous Boverty impacts
This last section looks at a few issues that are boverty related in varying degrees.
Cooking the planet
Globally we use almost as much biomass (as wood) for for heating and cooking as we eat. It amounts to about 10 percent of the 12.1 billion tonnes harvested or grazed. Remember we eat about 12 percent.
Many of the world’s poor have no choice but to cook and heat with biomass. Some not-so-poor people do it by choice. Typically the biomass is wood, but for poor people it can also be dung or crop residues. Burning biomass produces smoke. Smoke is an all-natural product containing a dazzling array of all-natural harmful chemicals. A US EPA approved wood stove generates very little smoke, but the stoves of the developing world generate plenty and have a death toll of about 1.4 million people each year. The main victims are women and children who spend more time near cooking stoves. Many of the smoke related respiratory infections wouldn’t be deadly with basic antibiotics and reasonable medical care.
Burning dung or crop residues out of desperate need or ignorance is tragic. The best use for dung is as fertiliser, and the best use for crop residues is to leave them to protect the soil. Biochar technologies are unlikely to change this in the short to medium term. Biocharing residues extracts and binds more carbon, but the cost is leaving soil uncovered.
One of the components of smoke is black carbon and which is a potent climate forcing as well as a serious health risk. Household biomass burning causes as much black carbon production as the world’s global wildfires, both natural and anthropogenic. Together they are responsible for about 40 percent of black carbon production. The warming impact of black carbon is tough to measure and was probably underestimated in early work, but may well be up there with methane and carbon dioxide as one of the big climate change culprits. The long term health impacts of black carbon are many but include cardiovascular disease. So if you wonder why they get heart disease in Nigeria despite low intake of animal products, look no further than burning biomass.
There have been a variety of recent initiatives to design and distribute more efficient biomass cookers, but the low energy density of dung makes complete combustion to minimise harmful emissions a particularly difficult design problem under the strict cost constraints (Prof. Kirk Smith, by email). The 3 billion people who cook with biomass desperately need better energy sources. They shouldn’t be burning animal dung or crop residues. Burning biomass of any kind in primitive stoves is thus both a significant health and greenhouse issue.
Ozone’s jekyll and hyde show
As the largest source of anthropogenic methane, livestock are partly responsible for another all-natural dangerous pollutant: ozone.
The global increase in atmospheric methane to more than double pre-industrial levels in recent decades is the main cause of the increase in the background level of tropospheric ozone.
Ozone is a good guy up in the stratosphere where it protects us from UV radiation, but a bad guy at ground level. Spikes in ozone levels occur in polluted areas thanks to sunlight acting on chemicals called VOC (volatile organic compounds). VOCs are a broad class of chemicals, encompassing things as diverse as petrochemical pollution fumes and the most delicious of cooking smells. Unhappily modern living seems to create more VOCs like the former than the latter. The resulting ozone spikes cause increases in asthma, bronchitis and heart attacks … to name but a few.
Wildlife or cattle, choose one
In July 2009 a major study confirmed what some African wildlife experts had long suspected. Key species in Kenya had declined by some 40 percent over the past 30 years, both inside and adjacent to national parks. The causes: poaching, bush meat, habitat destruction and human encroachment.
Kenyan rangers recently ejected 10,000 cattle from Tsavo West park. Massive cattle tracks visible from the air also show that herders have been illegally driving their cattle into the heart of the Masai Mara National reserve.
The story in Africa has direct parallels with the history of livestock expansion in the US, Australia and Brazil. Australian pastoralists have long seen deforestation as a legitimate farming practice.
In semi-arid areas of Africa and elsewhere grazing can accelerate desertification in various ways. Cattle eat a patch bare and trample it hard. This decreases the amount of water that enters the soil, instead it runs on to vegetated areas which increase in growth because of additional water. This focuses grazing on the patches of vegetation which remain. This creates a postive feedback and patchiness results. More generally, grazing changes surface reflectivity (albedo) which can act as a further positive feedback on a large scale. This has been found to change soil temperatures and rainfall in the African Sahel as well as India. Smaller impacts have been found in comparisons between areas differentially grazed along the US/Mexico border.
Cattle, goats and V8 utes
I began the first part of this post with an analogy about SUVs and their societal impacts. There is a related automotive analogy that probably has more explanatory value, particularly for Australian audiences. Visit any country town in Australia and you will see an impressive collection of utes, often with huge V8 engines. A ute is the Australian equivalent of a “pickup” in the US. A V8 ute earns its owner considerable prestige within their circle of peers, but absorbs petrol like a parched flood plain. Dollars which could go into education and high quality food for a family ends up vanishing into the ute for a tiny transportation payback.
So it is with livestock in Africa, sometimes aided and abetted by aid organisations trying to satisfy the dangerously dysfunctional aspirations of people with strong cultural bonds to cattle. This week’s Lancet editorial was too polite (or scared of legal consequences) to name the aid organisations it attacked, but it certainly spread plenty of shame. The various “Livestock for Africa” begging campaigns are excellent examples of what happens when aid agencies lose the plot.
Terminology: Grasslands and Savannas
In this article, I’ve used the terms grassland and savanna without paying any attention to the technical differences. Savannas are sprinkled with trees. The timing and amount of rainfall tends to be different also. Scientist have various sub-categories, some of which occur naturally. Elephants seem to be the only other species besides us which can make savannas. In some circumstances, cattle can destroy grasslands. Their preference for grasses allows woody vegetation to gain a hold … this is the start of reforestation. Without people or lightening to burn this, or enough active browsing, some kind of forest will probably reassert itself.
Digression on Protein
Livestock producers and advocates generally have such a profound ignorance of nutritional issues that they often talk as if meat and protein are synonomous while vegetable protein is an oxy-moron. A cursory check of the WHO Food Balance Database tells a different story. Meat in all its forms provides just 17 percent of global protein. Animal products in total, provide just 40 percent. Increasingly, the weapon of choice against life-threatening undernourishment in children is plumpy’nut. This is pretty much a vitamin and mineral fortified peanut butter which outperforms the older vitamin and mineral fortified milk-powder based F100 formula. A newer wheat based solid product, BP100, is also available.
Plumpy’nut is often described as a high protein high energy spread. It is described this way because the nutritionists involved know what they are talking about. They know that the protein requirements of people are very low, about 7 percent of calories. Plumpy’nut has about 10 percent of its calories as protein … which makes it high. But vague words like high and low can change meanings depending on the context. In the advertising jargon world of popular nutrition hype, this is a low protein food. For comparison, the CSIRO Total Wellbeing Diet recommends 30 percent of calories from protein and is based around a food, lean red meat, which typically has 80 percent of calories as protein. So in a typical western context it is quite misleading to call this food high protein. In common parlance, plumpy’nut should be described as a low protein, plant based, high energy, life saving food.
One notable advantage of both Plumpy’nut and BP100 over F100 is that F100 looks like milk formula. This can undermine efforts to have mothers breast feed instead of using infant formula.
Yams is pretty much a generic term in western countries, often meaning sweet potato (which aren’t really yams), but the various Dioscorea, true yams, typically have very low nutrient density, but a high ratio of nutrients to calories, particularly minerals like iron and zinc and protein. For example, some have more than half their calories as protein.
Digression on Fish
For those who have swallowed, hook line and sinker, the fish industry propaganda that fish is brain food or a vital global source of protein … both are excellent examples of the old maxim, if you must lie, tell a whopper and tell it often.
Globally, fish and seafood is about 1 percent of calories and included in the 17 percent provided from animal sources in part 1 of this post. We are, in effect, trashing the oceans for an entirely superfluous food. The campaign to persuade people to eat fish as brain food is simply junk science gone crazy. The Japanese have a per-capita fish consumption 5 times that of the Australians, Germans, Chinese or Americans. Has all that fish made them smarter? The whole notion of brain food is based on deeply flawed reasoning. One of the world’s foremost experts on IQ, James Flynn recently wrote an article Requiem for nutrition as the cause of IQ gains. The name says it all.
Industrial fishing hauls vast amounts of sea life out of the ocean and extracts the small amount which is valuable. The rest is called bycatch. Jonathan Saffran Foer’s interesting new book Eating Animals paints an accurate picture of the mind numbing (usually ignorant) destructiveness of almost all people who eat fish: If a plate of sushi was served with all the bycatch associated with its production, then the plate could be around 5 feet wide. In some cases, seafood bycatch also includes people. Many of the 146,000 people killed by cyclone Nargis in Burma in 2008 died because the mangroves which used to protect the coastline had been cleared for prawn farms.