The Institute for Energy and Environmental Research in Heidelberg has calculated that the production of olive oil requires the most water in this comparison: 900,000 litres of water equivalent (WA) per kg of food (Reinhardt et al. 2020).

The paper describes a WEE as the "equivalent volume of water of average scarcity required for the food".

For comparison: soya granules consume 30,000 wt, beef 20,000 wt and sugar 90 wt. Per kilogramme of food.

Further values for comparison: 1 kg of apples requires 1500 litres of water equivalents, rice 60,000. However, when classifying the foodstuffs, it is unclear how they were grown and what the feed for the cattle, for example, consisted of. There are very large differences in water and energy consumption depending on the cultivation method and location.

We refer to the following source:

https://regional-klimaneutral.info/wp-content/uploads/2020/07/Ifeu-Studie-2020-%C3%B6kol.-Fu%C3%9Fabdr%C3%BCcke-Co2.pdf

As we are talking about food in Germany here and the literature values differ greatly in some cases, we are limiting ourselves to the source, so the answer can be seen more as a guideline.