It has been estimated that about 2 billion people worldwide live primarily on a meat-based diet and about 4 billion people worldwide live primarily on a plant-based diet. Statistics from the USA show that the average person eats around 124kg of meat each year, that's about 350g of meat per day (~3 x the weight of your iphone).
It takes ~6kg of plant protein to feed the livestock (i.e. the cow, the sheep, etc.) to produce 1kg of meat protein.
Food costs energy and energy costs food
Looking at energy costs for animal protein production, it takes:
~ 4 calories of fossil fuel energy to produce 1 calorie of chicken protein
~ 10 calories of fossil fuel energy to produce 1 calorie of milk protein
~ 40 calories of fossil fuel energy to produce 1 calorie of beef protein
~ 57 calories of fossil fuel energy to produce 1 calorie of lamb protein
When considering the average of all animal foods, it takes ~25 calories of fossil fuel energy to produce 1 calorie of animal protein. This means these animals need to consume excessively high amounts of calories to produce small amounts of protein calories in return.
Notably, if these animals were fed solely on a good-quality pasture, the energy inputs required would be halved.
Looking at energy costs for grain (e.g. wheat, oats) production, it takes:
Compared to animal protein production, the energy input for grain protein is more than 10 times less.
Food costs water
When accounting for water use, it takes 100 times more water to produce 1kg of animal protein than it does to produce 1kg of grain protein.
It takes ~100,000 to 200,000 litres of water to produce 1kg of beef.
Looking at these numbers, you can see that a meat-based diet requires significantly more fossil fuel energy and water, than that of a plant-based diet.
A very large study with very large findings...
On the 1st of June 2018, a very large study was published on the environmental affects of food. The study analysed the environmental impacts of over 38,000 farms from around the world, and found that limiting or avoiding meat and dairy foods from one’s diet could reduce an individual’s carbon footprint by over 70%. Further to this, the study showed that if everyone stopped eating meat and dairy foods, global farmland could be reduced by up to 75%.
If you limit (or avoid) the consumption of animal foods, this delivers far better environmental benefits than cutting your use of electricity, taking fewer flights overseas, getting solar panels or even buying and driving an electric car.
Your food choices affect more than you...
When choosing the foods you eat, it is essential to consider the impacts that your food choices have on the environment. Beyond just reducing food packaging, recycling properly, or even going plastic free, we need to understand that there are substantial environmental costs associated with particular types of foods. This is based on the way the food(s) are produced, as well as processed.
Producing meat and dairy foods requires very large amounts of fossil fuel energy and water, as well as large amounts of feeds, fertilizers and pesticides. These types of foods also generate significant amounts of greenhouse gases, toxic manure and wastewater.
Significantly, between 1971 and 2010, the worldwide production of meat tripled to over 270 billion kilograms. At this rate, production is predicted to double by 2050. That’s 540 billion kilograms of meat per year, which ultimately will require extreme amounts of water, fossil fuel energy, land, pesticides and fertilizers, resulting in significant impacts on the earth.
It has been estimated that if Western dietary trends continue, by 2050 they will be a major contributor to an estimated 80% increase in global agricultural greenhouse gas emissions from food production and land clearing.
No... you don't have to go Vegan...
Although going Vegan may be one of the best ways you can eat for the earth, you do not have to take this extreme approach. However, by simply reducing your intake of meat and dairy, you will be serving the earth a great deal of good service, setting it up to be a much better place for future generations.
Tips to eat for a healthier earth
You could start by trialling meat-free Monday's; instead base your meal around legumes or tofu.
Choose two nights per week to eat vegetarian; e.g. chickpea curry or tofu stir-fry.
Halve your meat portions.
Include fortified plant-milks (e.g. soy, oat, almond).
Not only will this benefit the earth, but it will also benefit your health in a number of significant ways.