I’ve found a better source of information on how much water almonds use and now have a better estimate of how much water per gram of fat and protein it takes to grow them. It’s about four times what I’d originally estimated, which makes them nowhere near as efficient as I’d originally estimated. Which makes sense — I always thought those numbers were wrong.
But even having adjusted those numbers, almonds are still slightly more efficient in terms of fat per gallon of water than cow’s milk, and use about half the amount of water per gram of protein as beef. So my original conclusion that beef is a far worse problem than almonds still stands, but I do now think almond farming is a problem.
Coconut milk appears to be a good alternative to almond milk, at least based on the So Delicious environmental footprint website. And based on the same report that I got my updated almond numbers from, hazelnuts use almost as much water, in total, as almonds, but use very little irrigated water.