Poverty and Plant-Based Diets

Forty years ago, Frances Moore Lappe wrote Diet for a Small Planet, a combination cookbook and food industry critique. In it, she pointed out that the grain we feed to livestock animals could instead be fed to hungry people.

The recent shock in food prices has led to increased examination of food cost determinants, and the data provides interesting insights into how our diets can affect the lives of the world's poor.

The Numbers

According to Counting Animals, a vegetarian saves 29 chickens, 1/2 of a pig and an eighth of a cow each year. Using the formula developed by Fortenbery and Park, 9 million such vegetarians would reduce the price of corn by $5/bushel. Using this as a proxy for soy, food prices of the ten staple foods would drop by 20%1. This corresponds2 to the central scenario of Dessus et al.,estimated to cause 233.2 million people to come out of absolute poverty (defined as living on less than $2/day). Using Goklany's estimates, this would avert 1.22 million deaths, and 42.7 million disability adjusted life-years.3

To put it in personal terms: one vegetarian saves one human for every eight years they're veg, and averts four DALYs per year of vegetarianism.

Cost Effectiveness

EAA has previously estimated that the top charities create one vegetarian-year for around $11. This means that top veg charities save one person for $90, and spend around $2.75 to avert a DALY. For comparison, the Against Malaria Foundation, GiveWell's current top pick, spends $2,300 per life saved or between $29 and $169/DALY.

Even with the generous padding that these rough calculations deserve, veg charities may be competitive with other poverty-focused charities.


Code used to calculate these numbers can be found here.
  1. This would cause a drop in soy and corn prices of 63%. However, these foods make up only a third of total global staples, meaning that aggregate staple price would drop by only ~20% (ceteris paribus). Note that Fortenbery and Park's model probably wouldn't handle such a large change well, so this should be considered a very rough estimate.
  2. Dessus and Goklany both examined the other direction: how many more people would enter poverty as the result of increased food prices. I assume here that the change is symmetric, i.e. the badness caused by an increase of $x is the same as the goodness caused by a decrease of $y
  3. Goklany separates DALYs meaning "disability with no death" from actual deaths, in contrast to places like GiveWell, which usually include premature death in their DALY calculation.