Vegetarian vs Vegan: Which Diet Has a Lower Carbon Footprint?
Quick answer: The average Western diet produces roughly 2.5 tonnes CO₂e per year. A vegetarian diet cuts that to about 1.7 tonnes, while a vegan diet brings it down further to around 1.5 tonnes. Vegan is lower mainly because dairy cheese and eggs still carry significant emissions. But here is the surprising part: the biggest gain comes from eliminating red meat, not going fully vegan. Eliminating beef and lamb alone gets you about 80% of the way from a standard diet to a vegan one. See our Beef vs Chicken comparison for more on why red meat dominates food emissions.
Annual Emissions by Diet Type
| Diet Type | kg CO₂e per year | Reduction vs High Meat |
|---|---|---|
| High meat (>100g/day) | 3,300 | Baseline |
| Medium meat (50-100g/day) | 2,500 | -24% |
| Low meat (<50g/day) | 1,900 | -42% |
| Pescatarian | 1,750 | -47% |
| Vegetarian | 1,700 | -48% |
| Vegan | 1,500 | -55% |
Source: Poore & Nemecek (2018), published in Science. Annual figures based on average UK intake patterns extrapolated from per-product data.
Where the Difference Comes From
The gap between vegetarian and vegan diets is mostly about dairy and eggs. Here are the key products that vegetarians still consume but vegans do not:
| Product | kg CO₂e per kg (or litre) | Plant Alternative | kg CO₂e per kg (or litre) |
|---|---|---|---|
| Cheese (hard) | 21.0 | Nutritional yeast | ~2.0 |
| Eggs | 4.5 | Scrambled tofu | ~1.5 |
| Cow's milk | 3.2 (per litre) | Oat milk | 0.9 (per litre) |
| Butter | 11.9 | Plant-based margarine | ~3.3 |
| Yoghurt | 2.5 | Soy yoghurt | ~1.0 |
Source: Poore & Nemecek (2018). Plant alternative estimates from Clune et al. (2017) and industry LCA data.
Cheese is the single biggest outlier. Because it takes roughly 10 litres of milk to make 1 kg of cheese, its emissions per kilogram are extremely high. A vegetarian who eats a lot of cheese can have a carbon footprint closer to a low-meat diet than to a vegan one.
Is Vegan Always Better?
Not necessarily. There are cases where a vegan choice can be worse than its non-vegan equivalent:
- Imported avocados — Avocados shipped by air freight from South America can carry 1-2 kg CO₂e per fruit, partly offsetting their low farm-level emissions.
- Almond milk — While low in carbon (~0.7 kg CO₂e per litre), almond production is extremely water-intensive, requiring roughly 6,000 litres of water per litre of milk. This is primarily a water scarcity issue rather than a climate one.
- Rice — Rice paddies produce significant methane due to anaerobic flooded conditions. Rice has a higher carbon footprint than most other grains (~4 kg CO₂e per kg vs ~0.8 for wheat).
- Local eggs vs imported soy — Locally sourced free-range eggs can sometimes have a lower total footprint than heavily processed soy products shipped from overseas, depending on supply chain specifics.
The lesson is not that vegan is wrong — it is almost always lower in carbon. Rather, what you eat matters as much as whether you eat animal products. A vegan diet heavy on air-freighted produce and processed substitutes may not outperform a simple vegetarian diet built around local vegetables, grains, and legumes.
The Biggest Lever: Red Meat
The data consistently shows that red meat is the dominant driver of food-related emissions. Consider this comparison:
| Diet Change | Annual CO₂e Saving | % of Full Vegan Switch |
|---|---|---|
| Eliminate beef and lamb only | ~1,300 kg | ~72% |
| Eliminate all meat (become pescatarian) | ~1,550 kg | ~86% |
| Eliminate all meat and fish (become vegetarian) | ~1,600 kg | ~89% |
| Eliminate all animal products (become vegan) | ~1,800 kg | 100% |
Reductions calculated relative to a high-meat diet (~3,300 kg CO₂e/year). Source: Poore & Nemecek (2018).
Simply removing beef and lamb — without touching chicken, fish, dairy, or eggs — captures roughly 72% of the total benefit of going fully vegan. Going vegetarian gets you to about 89%. The final step from vegetarian to vegan delivers a meaningful but comparatively smaller reduction.
This is why the IPCC AR6 report highlights reducing ruminant meat consumption (beef, lamb, goat) as one of the single most impactful dietary changes for climate mitigation.
Frequently Asked Questions
Is a vegan diet always better for the environment than a vegetarian diet?
In terms of greenhouse gas emissions, yes — a vegan diet is almost always lower. The average vegan diet produces about 1.5 tonnes CO₂e per year vs 1.7 for vegetarian. However, other environmental factors like water use (almond milk) and biodiversity (soy monocultures) can complicate the picture.
What single food change has the biggest carbon impact?
Eliminating beef and lamb. These ruminant meats produce methane and require vast amounts of land and feed. Cutting just beef and lamb from your diet can reduce your food emissions by roughly 1,300 kg CO₂e per year — about 72% of the benefit of going fully vegan.
How does cheese compare to meat in terms of emissions?
Hard cheese produces about 21 kg CO₂e per kilogram — more than pork or chicken. Because cheese concentrates the emissions of milk production, a vegetarian who eats a lot of cheese can have a surprisingly high food carbon footprint.
Data sources: Poore, J., & Nemecek, T. (2018). Reducing food's environmental impacts through producers and consumers. Science, 360(6392), 987-992. IPCC AR6 WGIII (2022), Chapter 7: Agriculture, Forestry and Other Land Uses (AFOLU). Clune, S., Crossin, E., & Verghese, K. (2017). Systematic review of greenhouse gas emissions for different fresh food categories. Journal of Cleaner Production, 140, 766-783.