Who grows the most? Who eats the most? The impact of global caloric staples by Andrew Ormerod

Interactive talk for Eden Food Week 2005 – event organised by Andrew Ormerod

Theme – “Global Agriculture – food and nutrition issues

A modern quest for food
In the 1950’s supporters of Malthus ideas foresaw the growing world population outstripping food supply.

Late 1950’s Quest for protein
At the end of the 1950’s protein was considered to be key to staving off famine. Based on studies of cases of kwashiorkor in Africa. Further studies by nutritionist Roger Whitehead suggested that, original conclusion from Cicely Williams that condition was mainly due to protein malnutrition was incorrect. His findings suggested that it was due to worms, incipient pellagra and calorie and protein shortages.

1960’s Quest for calories
So the emphasis swung to increasing sources of calories in the 1960’s and accelerated the development of the high yielding cereals that formed part of the ‘Green Revolution’. .

21st century – Quest for dietary diversity and micronutrients
Post the Green Revolution – as we move into the 21st century there is increasing awareness about the need for dietary diversification and the role of micronutrients in our diet.

Micronutrients of note
A, Iron
B, Zinc
C, Carotenoids (Vitamin A precursors – and anti oxidants)

D, Selenium – Via soil improvement and species that accumulate more selenium.
E, Iodine – mentioned by Roger Whitehead – need to check dietary sources of iodine.

Millennium development goals
There are millennium development goals and the first aims to eradicating extreme hunger and poverty by 2015.

Population growth – predicting future food needs
World population is predicted to stabilise by 2050 and will hopefully remain at this level for about a 1,000 years.  Experts believe that crop outputs need to double by 2050 to keep pace with population growth.  Urbanisation is increasing, but the rapid growth in population in the 60’s and 70’s isn’t expected again.  World population is likely to be ageing as people live longer.  This has consequences on the calculations of the amount of food energy required as food energy is affected by size, gender and age of people. Older people generally don’t have the same appetite or energy requirement as younger people. If ageing populations are taken into account this may reduce the predicted future food requirement.  On the other hand increased affluence in the developing is strongly linked to increasing demand for meat – which will mean increasing demand for crops such as maize and wheat as animal food.

Plants for food – caloric staples

There are around 270-400,000 species of plants on the planet of which humans use 7,000, but only 30 provide 90% of the calories, while 3 species wheat, rice and maize provide around 68% of the worlds calories.  Sugar, millet and sorghum and soybean oil are also important global sources of calories as are potatoes and sweet potatoes.

Maize, Wheat, Rice and Potatoes

Maize, wheat and rice alone are staple foods for around three-quarter of the world’s population.  Back in the 1960’s there was great concern – would there be enough food to feed the burgeoning world population?  

Green Revolution

At this stage new high-yielding semi-dwarf wheat and rice varieties were introduced, contributing to the ‘Green Revolution’ along with improvements in irrigation, fertilisers and chemical controls to improve food supplies and prevented the predicted mass starvation.  The ‘Green Revolution’ helped developing countries like India to become self-sufficient in rice and wheat. The increase in wheat, rice and maize production has roughly kept track with world population over about forty years.  However incremental yield increases to keep track of population growth have become more difficult to achieve in more recent years.  In this period the area planted didn’t changed dramatically, indicating that increased production was linked to yield increases.

Although there is enough food currently to feed the world, many people do not have access to it due to poverty and uneven distribution of food, storage losses are an additional problem. Some predict crop output needs to double by 2050 to keep pace with world population growth.

Maize, wheat and rice together with potatoes, represent the most important starchy staples in terms of tonnes harvested a year.


Rice is the world’s most important human food feeding over half the world’s population. Around 90% is consumed in Asia, where 70% of the world’s poor live and many eat rice two or three times a day. The ‘Green Revolution’ increased yields at a faster rate than population growth, making rice cheaper for the poor, but future demand for rice is likely to grow, particularly in Western Asia.  About an extra billion rice consumers in Asia are predicted by 2020. Demand is also likely to grow substantially in sub Saharan Africa. The challenge for the future in Asia is to produce more rice economically from less land and less inputs like water. By contrast rice consumption has declined to some degree in more affluent countries in Asia, for example, Japan and South Korea; where demand for wheat has been increasing associated with wider consumption of a more Western diet.


Wheat, once a temperate crop, is now the most widely cultivated geographically, having adapted to different climatic conditions in the last 30 years. It is the staple food for 35% of the world’s population. The presence of elastic gluten protein in the seeds, has increased its popularity due to its versatility and the range of products that can be made from it. Demand for wheat will carry on increasing, especially for animal feed. In the developing world demand has increased by 5% per annum and about 50% of the world’s wheat was consumed their, demand is predicted to rise to around 70% by 2020.


A greater global tonnage of Maize is harvested every year than wheat or rice but over 70% of maize seeds are used for animal feed. This market for predominantly yellow seeded maize has increased in the developing world, particularly in Asia and China especially as increasing affluence has stimulated demand for meat. Demand for maize will continue to grow faster than wheat and rice by 2020, mainly for animal feed. White-seeded maize is traditionally preferred as human food, in Latin America (particularly Mexico) and South and East Africa, where demand is likely to remain strong in the next 20 years. Maize is a staple used to make tortillas and other maize dishes in Meso America – its centre of origin.

Nixtamalisation – The Aztecs innovation to improve nutrition in maize seeds.

Alkaline treatments of maize seeds with lime water or ash were originally developed to make grinding easier. It has a fortuitous nutritional benefits, only understood in more recent years as it unlocks niacin – an important vitamin for human health. Maize spread around the world, after the arrival of Europeans in Latin America and has become an important staple in Africa. The importance of the lime treatment, however, was overlooked resulting in deficiency diseases such as pellagra occurring in communities that are over reliant on maize for food.

Modern methods to improve maize nutrition

In an effort to improve maize nutritional value Quality Protein Maize (QPM) was developed at The International Maize and Wheat Improvement Centre (CIMMYT) with improved amino acid balance in the seed (levels of lysine and tryptophan have been notably improved). The work on QPM won the World Food Prize for its developers in 2000. The improved nutritional balance has been developed to contribute to human nutrition and health, particularly in young children and also has advantages as an animal feed compared to conventional maize. Maize provides over 1,000 calories (of a recommended daily intake of around 2,500) in Malawi, Lesotho and South Africa.


Potatoes originated in the Andes. Once introduced to Europe they became an important staple, providing cheap forms of energy protein and vitamins for the population involved in Europe’s ‘industrial revolution’. They played an important role in feeding Ireland’s rapidly growing population in the early 19th century, until potato blight played havoc with the crop – resulting in starvation and migration.  Potatoes are still major sources of calories in Slavic countries such as Belarus, Poland and Estonia and Benelux countries (Belgium, Luxemburg and Holland). Interestingly, the French fry, now a global phenomenon, probably originated in Belgium.

Potatoes production, though significant, has been declining in the developed world over the last forty years. On the other hand demand has increased in the developing world since the 1960’s and is still increasing in Asia (particularly China), Africa and Latin America.

Bananas and Plantains

These are example of food crops in the ‘top twenty’ in terms of tonnes produced globally and they are the fourth most important crop in the tropics by nominal value. In Britain we think of bananas as a dessert fruit, but starchy bananas and plantains are important sources of daily energy. In East Africa countries such as Uganda, Rwanda and Burundi people eat up to 250 kg of Matooke bananas a year (compared with around 12 kg of bananas in the UK). The word ‘matooke’ is synonymous with food in East Africa. Here, bananas are also brewed to make a low-alcohol beer, which is rich in vitamin B due to its yeast content. Bananas are also important sources of carbohydrate in other parts of tropical Africa, in Asia and Latin America.

Improving nutritional value in world crops

There has been a change in emphasis towards nutritional requirements for the world’s growing population. Instead of pure yield increases there is now more emphasis on improving human nutrition through dietary diversification and through enhancing micronutrients in existing crops such as wheat, rice and maize. Trace amounts of iron and zinc play an important role in the human diet. Anaemia, caused by iron deficiency, is the most common nutritional disorder in the world; between 66 and 80 per cent of the world’s population may be iron-deficient – the majority in the developing world – the consequences can be serious for children and pregnant women during their potential reproductive years. In the case of rice, for example, it has been possible to increase iron levels in wheat by searching through genetic resource centres for appropriate strains – one of the challenges has been to get enhanced levels of iron bred into wheat plants expressed in the seeds.

Efforts are underway to enhance levels of carotene, which have dietary antioxidants properties, in a range of crops. Beta carotene, for example is the precursor of vitamin A which prevents blindness. Types of bananas and potatoes and sweet potatoes with yellow and orange flesh already exist are being investigated but work on vitamin A rich ‘golden rice’ has so far required the use of GM technology.


About cornucopiaalchemy

Dr. Andrew Ormerod has 14 years experience working as the Economic Botanist at the Eden Project - researching topical stories, artefacts, ethnobotanical inks, catering and retail links to exhibits. Previously I was involved with plant breeding and plant tissue culture working on a range of crops including winter cauliflowers, agricultural lupins, vining peas, wheat and barley and coconuts. I am now freelance and am interested in opportunities for lecturing; writing articles; consultancy linked to development of botanic gardens for crops based exhibits; supply chain work for unusual food or non-food crops with interesting stories about plants and people attached to them.
This entry was posted in About Andrew Ormerod Eden Project Economic Botanist, Eden Project - historic horticultural developments, Food week/month activities, Global food crops, Maize, Nutrition, Potatoes, Rice, Wheat. Bookmark the permalink.

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