A 2016 study comparing diet models with variations of vegan, vegetarian, and omnivorous found that a vegan diet was not the best for humanity if they wanted to feed the most amount of people with the land available.
The clear winner was dairy friendly vegetarian, followed by dairy and egg friendly vegetarian. This is because not all land is suitable for growing crops but is suitable for grazing cattle and other animals.
The vegan diet fell in the middle behind Omnivorous 20% and Omnivorous 40%.
In an interesting coincidence the study was partially funded by a grant from W.K. Kellogg Foundation. The foundation was formed in the 1930's by breakfast cereal pioneer Will Keith Kellogg.
A dairy friendly vegetarian diet would probably include lots of bowls of cereal.
As you can imagine, there were lots of feelings and opinions on this one.
Overpopulation by humans is the biggest environmental threat the planet faces.— peter kyte (@peterkyte2) August 6, 2016
brilliant, must send the link to my vociferous, mouthy, vegan sister in law!— Padstock (@twickydicky) August 6, 2016
@graymatterarea asked the question that was on all our minds.