Humans Are Becoming More Carnivorous

Study reveals global shift towards animal-based diet—a bad omen for the environment

 

 

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Image: Wikimedia Commons/Jon Sullivan

The fast-growing economies of China and India are driving a global increase in meat consumption, cancelling out decreases elsewhere, according to a comprehensive study of global food consumption.

The work, published today in Proceedings of the National Academy of Sciences, takes a detailed look at what people eat, as well as trends from one country to the next. It is also the first time that researchers have calculated humanity’s trophic level, a metric used in ecology to position species in the food chain.

The metric puts plants and algae, which make their own food, at trophic level 1. Rabbits, which eat plants, occupy level 2. Foxes, which eat herbivores, sit at trophic level 3. Cod, a fish that eats other fish, claims level 4. Polar bears and orcas, which have few or no predators and eat other mammals with gusto, hold the top positions — levels up to 5.5.

The study, led by Sylvain Bonhommeau, a fisheries scientist at the French Research Institute for Exploitation of the Sea in Sète, estimates that humanity’s global median trophic level was 2.21 in 2009, which puts us on a par with other omnivores, such as pigs and anchovies, in the global food web. “We are closer to herbivore than carnivore,” says Bonhommeau. “It changes the preconception of being top predator.”

Moving up
The study also looked at how eating patterns have changed over time. The researchers calculated the human trophic level for 176 countries for each year from 1961 to 2009 using a data on 102 types of food — from animal fat to yams — compiled by the Food and Agriculture Organization (FAO) of the United Nations.

Globally, the human trophic level increased by 3% from 1961 to 2009, driven largely by more meat consumption in India and China.
Image: Bonhommeau, S. et al. Proc. Natl Acad. Sci. USA

Over 50 years, an increase in fat and meat consumption has moved us further up the food web, with the global median human trophic level increasing 3% — or about 0.06 — during the period.

“It seems like a small difference, but when you think about how it’s calculated, it’s big,” says Thomas Kastner, an environmental scientist at Alpen-Adria University in Vienna, who was not involved in the study. An organism’s trophic level is calculated by summing the trophic levels of the foods in its diet and the proportion in which they are consumed. “A change by 0.1 means you are eating considerably more meat or animal-based foods,” says Kastner.

Regional differences
But changes were not uniform across the globe. Countries such as China and India, where hundreds of millions of people have lifted themselves out of poverty — and often out of diets that involved little more than rice — have shown marked increases in their trophic level. However, places such as Iceland, Mongolia and Mauritania, where traditional diets are mostly based on meat, fish or dairy, have seen their trophic levels decline as they diversified their daily fare.

Calculating human trophic levels reveals our place in the ecosystem and can help scientists to understand human impact on energy consumption and resource strength. Calorie for calorie, the environmental impact of producing meat — in terms of everything from carbon emissions to water use — is typically many times larger than that of producing vegetable foods. Furthermore, a 2006 FAO study found that the livestock industry is directly or indirectly responsible for 18% of global greenhouse-gas emissions — a larger share than all modes of transport combined. “If we all increase our trophic level, we’ll start to have a bigger impact on ecosystems,” says Bonhommeau.

This article is reproduced with permission from the magazine Nature. The article was first published on December 2, 2013.

 

 

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  1. 1. carpefishus 04:26 PM 12/3/13

    “It changes the preconception of being top predator.” That distinction is held by a trophic level 1.

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  2. 2. Sisko 05:08 PM 12/3/13

    Isn’t it only a “problem” for the environment if humans make the decision to breed uncontrolably and not manage their population?

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  3. 3. Trafalgar 12:18 AM 12/4/13

    Humanity? Make a responsible decision? Surely you jest.

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  4. 4. AnyaZhao 01:16 AM 12/4/13

    Why point out Chinese and India?! Why won’t point out the rich countries’ trophic levels doesn’t drop to the average level yet?! So what?! Chinese and India can’t eat meet as much as what the westerns have been doing for hundreds years?

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  5. 5. AnyaZhao 01:21 AM 12/4/13

    Humans are always on the same trophic level, the difference is, in the past a lot of people could afford the food with meat, but now they can afford it and they just do it.
    The conclusion of this research is misleading.

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  6. 6. snusify 08:31 AM 12/4/13

    Given that we spent millions of years evolving from early ape men to modern humans up until about 10000 years all we had ever eaten was mostly meat and seasonal fruits and greens.

    So today we are not becoming more carnivorous we are returning to the diet that we are genetically predisposed to.

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  7. 7. papasmurph in reply to AnyaZhao 08:51 AM 12/4/13

    It’s the same way emerging and less powerful countries are forced to lower their CO2 footprint, while the biggest polluters (including USA) go mostly free, because companies there can pay to go free.

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  8. 8. Indrasblade77 09:23 AM 12/4/13

    What a pile of New World Order propaganda!

    They want us off meat to leave us weak, sickly and malnourished to make us more controllable and easy to dominate as the population will be reliant on drugs, and undermuscled due to lack of protein.

    They need us weakened as they push through their Orwellian world government and implement their new age feudal serfdom.
    This involves firstly destroying society in order to offer the world government as a solution. By the end of the ‘Order out of chaos/divide and conquer’ phase implemented via economic sabotage, control and destruction of food and water, and war. Those who realise what’s going on will be too scared, poor, weak and sickly to resist and the remaining peasant masses will welcome the world government gullibly believing it will fix the world.

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  9. 9. Megahertz_Donut in reply to snusify 10:28 AM 12/4/13

    I’m sorry but that is simply not true that we evolved from a more carnivorous past. Like our ape relatives, we spent most of our millions of years as insectivores and frugivores. The only truly carnivorous primate is the tarsier; the rest of us are much more herbivorous no matter what your local bacon salesman has told you.

    Even as humans became more omnivorous, meat was never as large a part of our diet as it is now due to artificial cheapness from subsidies and modern farming techniques. Also keep in mind that throughout most of history, humans in different areas ate very different diets from each other as noted in the article.

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  10. 10. Megahertz_Donut in reply to Indrasblade77 10:28 AM 12/4/13

    Your paranoia is amusing, but unfounded.

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