Sustainability Q&A


Professor Harry Aiking is specialized in food security and sustainability. In nine questions and answers he summarizes the main issues about a sustainable diet.

1. What is a Sustainable diet?

Sustainability is a dynamic goal, covering ecology, economy and society (also known as people, planet, profit). A sustainable diet consists of food produced in a sustainable way, i.e. with low use of natural resources (such as land, water and energy) and low emissions of polluting compounds (such as pesticides, antibiotics and CO2). According to some, animal welfare and fair trade standards should be included, as well.

2. Are Plant-based foods more sustainable? Why?

Animals require nutrients and energy for their own metabolism, movement and body temperature. Direct human consumption of crops is invariably more efficient, therefore, than animal consumption of feed crops and subsequent human consumption of the animals. Grazing animals or animals fed waste products do not have that sustainability disadvantage, because grass and waste are unfit for human consumption and do not compete for natural resources like feed crops do.

3. What food consumption pattern would you consider to be most sustainable?

Obviously a diet based on plant foods, primarily, supplemented with animal-based foods deriving from grass-fed and waste stream fed livestock (including fish and insects).

4. Is a sustainable diet a healthy diet?

Interestingly, a comparison of sustainable diets and healthy diets shows that healthier diets (such as the Mediterranean diet, for example) are generally also more sustainable. The overlap is about 80%.

5. Why does food production has an impact on environment?

Due to its sheer bulk. In fact, over 30% of all ice-free land, 70% of all freshwater, and 20% of our annual energy production is used for food production. Currently, climate change receives a lot of attention, but anthropogenic contributions to the carbon cycle are 100-fold lower than to the nitrogen cycle. The latter is pivotal to protein production and is a major driver of biodiversity loss, for example.

6. To what extent is food production involved in climate change?

Food production requires substantial energy input from mineral fuels. Furthermore, when natural areas (such as rain forests) are converted into farmland, lots of CO2 are released from the soil and from plant biomass.

7. What advice would you give to the consumer to decrease his impact on the planet?

On average, Western consumers are consuming 60% more proteins than they require, and also more calories than they require. Both the environment and their own health would benefit from a substantial reduction of protein intake, primarily animal proteins. Consumers should consider a) eating one-third less protein, b) replacing one-third with plant-derived protein, and c) replacing the remaining animal protein (primarily meat) with protein from free-ranging animals.

8. What is the difference between animal and plant-based protein on climate impact?

Globally, the climate impact of livestock production alone far exceeds that of transport. The climate impact of plant-based protein may be an order of magnitude lower.

9. What is food security?

Food security exists when all people, at all times, have physical, social and economic access to sufficient, safe and nutritious food to meet their dietary needs and food preferences for an active and healthy life. The 4 pillars of food security are availability, access, utilization and stability. Food security used to be an issue in developing countries, primarily, but even in the UK some 4 million (over 6% of the population) are living in food poverty today. Furthermore, food prices are bound to rise, because by 2030 both mineral oil and phosphate production will start to decrease. Both are indispensable to feed a rapidly growing global population, which may reach 9 billion by 2050 (from 7 billion today).


For more information:

Aiking H. Protein production: planet, profit, plus people? Am J Clin Nutr 2014; ajcn.071209.


- Prof. Dr. Harry Aiking

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