A new study in Switzerland shows the impact dietary choices have on the environment. Compared to current eating habits, three different diets all roughly halve the environmental damage wrought by food production.
Put together by Agroscope, a Swiss government research centre, the analysis looks at scenarios that would reduce environmental damage while maintaining the current landscape and level of food exports. A fourth, looks at the impact of cutting food waste.
Changing to the healthiest of the three diets cuts the environmental impact of food by 51%.
Farming and food production do harm in three areas: using finite resources (9%), ecosystem damage (61%) and human health (30%), which includes greenhouse gas, ozone, nitrous oxide and other harmful emissions. The biggest gains are made in cutting ecosystem damage and things affecting human health, including climate change.
So what dietary changes are required?
The deepest cuts are to fruit juice (-91%), alcohol (-85%), meat (-70%), potatoes (-60%), fats and oils (-51%), and confectionary (-45%)1. Current meat, alcohol and fruit juice consumption levels are neither good for the environment or human health. Current potato, oil and confectionary consumption fail to deliver human health, but have decent environmental credentials, particularly potatoes which grow well in Switzerland.
In one study, the United Nations calculated that livestock account for 18% of global greenhouse gas emissions, more than transport, so it is no surprise that meat comes in for the chop. Nearly all meat eaten in Switzerland is environmentally damaging. Beef (-76), Pork (-91%), and poultry (-89%) all come in withered portions. The only exceptions are offal – probably much of this is wasted, and calf meat – an unavoidable by-product of milk production. The problem with Swiss chicken and pork seems to be the damage wrought by the food imported to feed them, for example soy beans grown where tropical forest once grew.
Wine, beer and fruit juice are an environmentally costly way to hydrate yourself. Nor are the calories in them, mainly alcohol and free sugar, known for any health benefits.
Foods that get a boost include vegetables (2.7x), fruit (2.2x), grains (1.6x), dairy (1.4x) – low fat milk but not cheese and butter, nuts (3.4x), tofu (19x) and pulses (4x)1. Eating more grains, nuts, tofu, pulses and milk appear to be broadly environmentally optimal. Eating more fruit and vegetables, while far better for the environment than meat, alcohol and fruit juice, gain an oversized share of meal plates partly for their health benefits.
The recommended rise in low fat milk consumption is unlikely to be environmentally optimal. One of the contraints given to modelers was to maintain “an open landscape”. To produce food, open landscape, or pasture, needs cows or other grass eating animals. If this constraint was lifted, to allow, for example, forests to replace pasture, the environmental impact of cows would be sure to count against them – cows emit large amounts of greenhouse gas and displace forests.
The fourth element of the analysis looks at food waste. Eliminating all waste, with no change to current eating habits, would cut the environmental impact of food by 61%. High-waste products include beer, wine, confectionery, tropical fruit, and fresh vegetables.
While the study shows some tradeoffs between human and environmental health, many of the suggested changes are win-win.
So what’s on the daily menu?
In round numbers:
- Vegetables – 700 grams, excluding potatoes (up from 250) – this is roughly 5 carrots.
- Fruit – 450 grams (up from 200) – this is roughly 3 apples.
- Grains and pulses – 350 grams (up from 200) – this is a couple of healthy servings. Within this number, wheat falls by 30% to 100 grams and barley rises from almost nothing to over 150 grams – barley is a healthy grain that grows well in Switzerland.
- Low fat milk – 470 mls (up from 290) – cheese drops from around 50 grams to less than 20 and butter and cream are virtually off the menu.
- Tofu – 20 grams (up from almost nothing) – this is a small cube.
- Potatoes – 50 grams (down from 120) – one raclette potato.
- Meat – 40 grams (down from 140) – this is a bit more than half of the meat on a typical chicken drumstick.
- Wine and beer – 40 mls (down from 280) – this is half a glass, a bit more or less depending on what’s in it.
- Fruit juice – this is effectively eliminated. Why have juice when you can eat fruit.
- Sugary things, excluding fruit juice, are down 45% to around 70 grams.