[bigstrat2003]

> alfalfa that doesn’t even feed people but requires an insane amount of water

Just because people don't eat the alfalfa doesn't mean it isn't ultimately feeding people. Cows eat a ton of alfalfa, and we get both meat and milk from them. So it is feeding people, just indirectly.

[littlexsparkee]

I think the point is it's an very inefficient way to get calories.

[egberts1]

Yet remains the most efficient way to get proteins.

PDCAAS and DIAAS by livestock are in the highly efficient category even after alfalfa water usage. Soy is just mid-tier.

So, depends on your body's protein needs. Vegan/vegetarian is just a choice and not for everyone.

[aziaziazi]

Let's look some data:

[edit: Soy Milk protein require 2.9x less water than Caw Milk protein, DIAAS adjusted: 1 / (0.28 * 1.25)]

   PDCAAS [0]
   Soy 0.92 - Beef at 0.94 (Beef 2% better)

   DIAAS [1]
   Soy 0.91 - Beef 1.116 - Whole milk 1.14 (Beef 23% better, Caw milk 25% better)

   WATER footprint [2]
   Soy Milk is 28% of caw milk (Soy 257% better)
   Soy Burger is 28% of caw milk (Soy 1329% better)

   CALORIC / PROTEIN fed population [3]
   MAD (mean American diet) 341m - Plant-Based 531m (plant 56% better)

0: https://ourworldindata.org/land-use-diets

1: https://en.wikipedia.org/wiki/Digestible_Indispensable_Amino... No data for Soy PDCAAS in that page and Beef has a different number as the first source. The difference isn't significative though.

2: > The water footprint of the soy milk product analysed in this study is 28% of the water footprint of the global average cow milk. The water footprint of the soy burger examined here is 7% of the water footprint of the average beef burger in the world.

https://www.waterfootprint.org/resources/Ercin-et-al-2012-Wa...

3: > [caloric and protein] At 3% in both metrics, beef is by far the least efficient [...] legume-dominated plant-based diets substitute beef with a dietary shift potential of ≈190 million [current US] individuals.

https://iopscience.iop.org/article/10.1088/1748-9326/11/10/1...

Obviously the production method of soy/burger/milk is significant, however others sources show rougtly the same order of magnitude: https://watercalculator.org/water-footprint-of-food-guide/

> depends on your body's protein needs.

For an higher protein/calorie ration, Quinoa is in range of soy' water footprint, and legume protein concentrates fit as well.

[egberts1]

Sure, soybean is holding up in its own way but it:

- lacks methionine. So eat more soybean or complementary proteins such as grains, legumes.

- contains Phytates, which reduce mineral absorption such as iron, zinc.

- contains Trypsin inhibitors that reduce protein digestion.

- contains Lectins

- comtains genistein and daidzein inducing estrogen while maintaining testosterone in male.

- a known allergen for 0.4-0.6% of population

- is overly used as ultra-processed filler instead of more expensive natural ingredients.

Then there is land-use issues and monoculture.

The number you gave while accurate ignores the overall issues.

[Analemma_]

The problem is that because farmers pay artificially low prices for their subsidized water, it distorts the price signals of the market. Who says cattle need to eat alfalfa? If they had to pay market rates for water, we’d probably find a more suitable crop that doesn’t need quite so much. But there’s no incentive right now to even try.