The Azimuth Project
Experiments in food return on energy invested


The concept FROEI is related to EROEI, in the case where the energy which is returned comes under the form of food (usually measured in calories). This nomenclature is by no means standard, but I suppose it is clear nevertheless, and it allows to establish, on this experimental page, our own precise definition without getting into disagreement with earlier literature.

In the literature there are discussions of EROEI in the context of food, but so far I have not been able to find a short name, or a precise definition (I’m still in the process of looking up), so I’ve (temporarily) come up with FROEI.

Probably the most direct way to define FROEI – for one type of food product that contains one calorie – is to make a life-cycle assesment of the energy invested in this food. However, it may be interesting to average the FROEI over a typical diet and compare it with the food needed by human beings (and possibly even taking into account the food wasted during an average lifecycle). One reason to do so is that without enough food for each individual, human civilization is under stress. Another reason to do so is because there are claims that current industrial agricultural practice has an FROEI of 1:10 while hunter-gatherer lifestyle yields 10:1. (Note: what about the energy necessary for cooking) This should be compared with the fact that industrial farming allows much greater population densities than hunting-gathering. (there is no inconsistency, fossil fuels supply the necessary energy, but anyway, I’d like to clarify matters for myself)


Historical evolution of FROEI

Typical herbivores

Typical carnivores

Human hunter-gatherers

Early farmers

Farming in middle-ages etc.

Industrial farming


Some claims (without further reference) can be found in

Still to read:

A tangential set of experiments about the energy used in various methods of cooking:

category: experiments