[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.