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The Balance of Health

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Cow's milk vs oat milk

A like-for-like swap in tea, coffee and cereal. Oat milk has far lower environmental impact but also much less protein.

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Same amount of protein from each food. Fairer for protein foods. That is 2,941 g of cow's milk against 10,000 g of oat milk.

Greenhouse gas emissions

kg CO₂e per 100 g protein

Oat milk has about 1.1 times the emissions of Cow's milk, so Cow's milk has the lower impact here.

Cow's milk: Roughly about 54 km of driving (Department for Energy Security and Net Zero, 2024)

Oat milk: Roughly about 58 km of driving (Department for Energy Security and Net Zero, 2024)

All greenhouse gases released producing the food, from land clearing to retail, expressed as carbon dioxide equivalents.

Calculation basis
  • Cow's milk: Poore & Nemecek (2018), OWID version accessed 2026-09-06; life-cycle assessment through retail, per kg retail weight.
  • Oat milk: Poore & Nemecek (2018), OWID version accessed 2026-09-06; life-cycle assessment through retail, per kg retail weight.
Oat milk: Global average

Land use

m² per 100 g protein

Cow's milk has about 4.0 times the land of Oat milk, so Oat milk has the lower impact here.

Cow's milk: Roughly about 0.1 tennis courts (International Tennis Federation, 2024)

Oat milk: Roughly about 0.03 tennis courts (International Tennis Federation, 2024)

Farmland needed to produce the food, including grazing and land for animal feed.

Calculation basis
  • Cow's milk: Poore & Nemecek (2018), OWID version accessed 2026-09-06; life-cycle assessment through retail, per kg retail weight.
  • Oat milk: Poore & Nemecek (2018), OWID version accessed 2026-09-06; life-cycle assessment through retail, per kg retail weight.

Water pollution (eutrophication)

g PO₄e per 100 g protein

Cow's milk has about 3.0 times the pollution of Oat milk, so Oat milk has the lower impact here.

Nutrient run-off from fertiliser and manure that causes algal blooms and dead zones, in phosphate equivalents.

Calculation basis
  • Cow's milk: Poore & Nemecek (2018), OWID version accessed 2026-09-06; life-cycle assessment through retail, per kg retail weight.
  • Oat milk: Poore & Nemecek (2018), OWID version accessed 2026-09-06; life-cycle assessment through retail, per kg retail weight.

Protein

g per 100 g protein

Cow's milk and Oat milk are about the same.

Protein content of the food as eaten.

Fibre

g per 100 g protein

Oat milk contains fibre; Cow's milk contains none.

Dietary fibre. Animal foods contain none.

Saturated fat

g per 100 g protein

Cow's milk has about 3.4 times the sat. fat of Oat milk, so Oat milk has the lower impact here.

Saturated fat content. Higher intakes raise LDL cholesterol.

Animals slaughtered

animals per 100 g protein

Neither involves slaughtered animals.

Approximate number of animals slaughtered for this amount of food. Small fractions mean one animal yields many portions. Zero for plant foods; dairy and eggs involve animals indirectly.

Calculation basis
  • Cow's milk: Approximate retail yield per animal inverted; yield assumptions are illustrative, not counts of individual animals spared.
  • Oat milk: Approximate retail yield per animal inverted; yield assumptions are illustrative, not counts of individual animals spared.
Methodology, sources and caveats
  • Environmental values use retail-weight averages, converted to the basis you choose. Nutrition can use cooked weight; preparation and proxy assumptions are listed below. Farms vary widely around these averages; thin lines on the bars show the reported range where the source gives one.
  • Where a food has figures for more than one country or production system, the default is the all-systems figure for your country (or the global average). The figure menu under a chart lets you choose another; the source and geography update with it.
  • Nutrient values are reference composition figures. Preparation and variety change them, and absorption differs between plant and animal sources (see the nutrient panel).
  • No single metric tells the whole story. A food can score well on emissions and poorly on water, or well on protein and poorly on fibre.
  • Freshwater use: Water use matters mainly where water is scarce. A litre in a rainy region is not equivalent to a litre in a drought-prone one, so treat this as indicative only.
  • Scarcity-weighted water use: Scarcity weighting depends on where each food is actually grown. Global figures blend many regions; country figures are shown where a source provides them.
  • Animals slaughtered: Dairy and eggs are shown as zero because no animal is slaughtered per unit sold, but both systems involve animals; this metric only counts direct slaughter.
  • Cow's milk: Nutrition approximates whole milk (FDC 746782); environmental data are per kg retail milk.
  • Oat milk: All environmental metrics use soy milk as a proxy: Poore & Nemecek has no oat-drink entry. Nutrition assumes a calcium-fortified drink, 120 mg per 100 ml, with no B12; check the product label.

Sources: Poore et al. (2018); Service (2024); Nations (2024). See how we rate evidence.

Cow's milk: sources and nutrients · Oat milk: sources and nutrients

In short, per 100 g of protein

  • Oat milk has about 1.1 times the emissions of Cow's milk, so Cow's milk has the lower impact here.
  • Cow's milk has about 4.0 times the land of Oat milk, so Oat milk has the lower impact here.
  • Cow's milk has about 3.0 times the pollution of Oat milk, so Oat milk has the lower impact here.
  • Cow's milk and Oat milk are about the same.
  • Oat milk contains fibre; Cow's milk contains none.
  • Cow's milk has about 3.4 times the sat. fat of Oat milk, so Oat milk has the lower impact here.
  • Neither involves slaughtered animals.

Change the basis above to see how the picture shifts by serving, weight or calorie. Build your own comparison in the full tool.