Questions & objections
The questions sceptical people ask
We start from the strongest version of each objection, say what is right about it, and then show what the evidence supports, what it does not, and what nobody knows yet.
- Environment
Is grass-fed beef sustainable?
Not in the way the claim suggests. Grazing can store some soil carbon, but reviews find it offsets only a fraction of cattle's own emissions, and only temporarily. Grass-fed beef usually has higher emissions per kg than grain-finished beef.
Moderate evidence - Environment
Isn't local meat better than imported plants?
Usually not. Transport is a small share of most foods' emissions, typically under 10%. What you eat matters far more than where it came from.
Strong evidence - Environment
Don't livestock mostly eat food humans cannot eat?
Partly true. Most livestock feed by weight is grass and crop residues. But a large share of the world's grain and almost all soy meal goes to animals, and the land used is enormous either way.
Moderate evidence - Animals
Does plant farming kill animals too?
Yes, crop farming does kill wild animals, and honest accounting should include that. But most crops are grown to feed livestock, so a diet with meat generally involves more crop farming, not less.
Limited evidence - EnvironmentAnimals
Does one person's diet actually matter?
In absolute terms one person's change is small, as it is for any collective problem. But diet is one of the few areas where an individual's impact is large relative to their other choices, and demand does shape production.
Moderate evidence - Health
Is a vegan diet safe for children?
Major dietetic bodies consider well-planned vegan diets appropriate for children, with attention to B12, iron, calcium, iodine, vitamin D, omega-3 and enough energy. 'Well-planned' is doing real work in that sentence.
Limited evidence - Health
Can vegan athletes build muscle?
Yes. Trials comparing plant and animal protein at matched total intake find similar muscle gains. Vegan athletes need a bit more total protein and should include leucine-rich sources like soy.
Moderate evidence
Coming next
Questions we are researching now. They will appear here once the evidence review is complete.
- Do vegan diets cause nutrient deficiencies?
- Does soy affect testosterone?
- Are plant-based meats unhealthy?
- Do vegans have weaker bones?
- Do we need fish for omega-3?
- Isn't vegan food expensive?