Where the numbers come from

💰 $730 a year

The app shows $730 a year, or €630 where prices are in euros. The dollar figure is a daily $2 multiplied out: 365 × $2 = $730.

I took $2 because it was the lowest of the three figures I could find:

• $750 a year in the United States, from a study in the Journal of Hunger & Environmental Nutrition
• $23 a week — about $1,196 a year — from a survey of 1,000 people in the US
• 600 € a year in France (2,400 € for a family of four), from one flexitarian's own accounting

Note the third of those is €600, not the €630 the app shows — the French estimate and the dollar one were gathered separately, and I compared them in May 2021 when the exchange rate made them close to identical. Food prices and exchange rates have both moved since. Treat either figure as the order of magnitude it is, not as your grocery bill.

💖 7 years

This one comes from Adventist Health Study 2, which followed tens of thousands of people for around twenty years and found that vegans, lacto-ovo-vegetarians and pesco-vegetarians all had significantly lower mortality than non-vegetarians.

Vegetarian Adventist men in that data live to 83.3 on average and women to 85.7 — 9.5 and 6.1 years longer than other Californians. Seven sits between the two. The same study found vegans around 30 pounds lighter than meat eaters, five points lower on BMI, and less insulin resistant; people who eat meat about once a week got what the authors called intermediate protection.

Be sceptical of any single number here, including mine. Studies like this take decades, and Adventists differ from their neighbours in more ways than diet — they also smoke less and exercise more. What the literature supports is the direction, not the decimal: plant-based dietary patterns are associated with health benefits. Worth reading alongside it: Snopes on whether vegetarians live longer and Christian Koeder on vegan mortality.

🐄 22 livestock and 🐟 350 aquatic lives a year

The land-animal figure comes from the FAO's FAOSTAT database, which Faunalytics presents readably. Twenty-two is an average for the Americas, and it is mostly chicken — small animals make large counts.

The aquatic figure I compiled myself, from the FAO's Global Production by production source 1950–2018 via FishStatJ, tonnages via Faunalytics, and counts of individuals from fishcount.org.uk. Honest caveat: my own working landed nearer 325, and the EU and the Americas came out suspiciously identical, which makes me think the regional split in the source data is partly artificial. Read it as hundreds a year, not as a count.

💦 29 showers a day

The water footprint of the EU for different diets puts the saving of a vegetarian diet against the reference diet at 1,611 litres per person per day — it is right there in the abstract.

A shower runs about 7 minutes and about 55 litres, per the Murray–Darling Basin Authority. So 1,611 ÷ 55 ≈ 29 showers a day.

🌳 1,423 apples a week

An ADEME engineer, quoted in an article by GoodPlanet, puts the land needed to feed one person in France at 5,200 m², against 1,200 m² on a plant-based diet. That is 4,000 m² freed.

Apples rather than trees, because the app is about food. A square metre of orchard yields 3–4 kg of apples and a kilo is 3–7 apples, so 9–28 apples per square metre; I took the middle, 18.5. That gives 4,000 × 18.5 = 74,000 apples a year, or 1,423 a week.

This is French land use. The general figure holds everywhere though — a plant-based diet uses roughly 75% less land. If you find the number for your country, send it to me.

🚗 22 miles per meal

The app shows 22 miles or 36 km depending on the units your region uses, which is the same distance twice. It comes from ADEME's Base Carbone, which compares a meat-rich meal at 7,260 gCO₂e with a plant-based one at 510 gCO₂e — a difference of 6,750 gCO₂e per meal.

A French car averages about 185 gCO₂e per kilometre, so 6,750 ÷ 185 ≈ 36 km, which is about 22 miles. American readers: the EPA puts a typical passenger vehicle at 404 g per mile, roughly 35% higher — but the United States also eats about 20% more meat than France, and more than twice the beef, so the two adjustments push in opposite directions.

🌐 The 7 goals it moves

This one used to have a tile of its own and no longer does, but it is still the frame I think in. The UN's 17 Sustainable Development Goals are the blueprint the world agreed on, and eating less meat moves seven of them:

• 2 — Zero Hunger
• 3 — Good Health and Well-being
• 6 — Clean Water and Sanitation
• 12 — Responsible Consumption and Production
• 13 — Climate Action
• 14 — Life Below Water
• 15 — Life on Land

The work underneath all of it

These are the papers I keep going back to when a number needs checking:

• The Synthesis Report of the IPCC Fifth Assessment Report
• Shifting Diets for a Sustainable Food Future (World Resources Institute)
• Environmental impacts of food production — Our World in Data's summary of the current literature
• Poore & Nemecek (2018), which consolidated data from about 38,000 farms producing 40 goods. Worth reading with the scientists' commentary on how it was reported
• The Impacts of Dietary Change on Greenhouse Gas Emissions, Land Use, Water Use, and Health: A Systematic Review

Your mileage will vary

All of these depend on where you live, what you eat now, and what you are aiming at. Most of the studies are US- or EU-centric, and the gap between countries is not small: the FAO has the United States eating 125 kg of meat per person per year, about 20% more than France, and 53 kg of that beef against 23 kg in the European Union.

So take the figures as the size of the thing, not as your personal total. What survives every caveat is the direction: fewer meaty meals means less land, less water, fewer emissions and fewer animals, every time. If you want your own numbers rather than mine, the footprint calculator runs them for the meat you actually eat.