1. Simulation of the agroecological production of balanced food baskets: case of Graux
Estate.
Manu Lambert1
, Alain Peeters2
and Elisabeth Simon3
(1)
ULB, Research Unit of Landscape ecology and plant production systems (2)
RHEA
Research Centre and (3)
Graux Estate.
Agroecological initiatives are being developed by farmers and farmer’s candidates convinced
of the need for a different food system. As a consequence, food self-sufficiency is slowly
emerging through the development of social and economic innovations. These farmers often
adopt short and local food marketing chain, for instance through food baskets. It is therefore
interesting to compose such baskets with healthy and nutritious products. In this framework,
the project of the Graux Estate (Tournai, Hainaut Province, Belgium) aims at producing food
directly for consumers, in proportions sticking to the population’s needs and through
agroecological techniques.
Scientific knowledge on human nutrition constantly evolves, as well as the official nutritional
recommendations. These standards may be influenced by the lobbying of agrobusiness
industries and their reform after new scientific findings is slow and limited, sometimes
leading to contradictions between ancient and new concepts. A large range of diets is also
proposed and defended. Among these, the ‘paleolithic’ or ‘gather-hunter’ diet stands out for
its scientific hypothesis based on evolutionary medicine (Eaton and Konner, 1985; Cordain
et al., 2005; Konner and Eaton, 2010). These hypothesis state (1) that human beings, like
every species, evolved and adapted according to the environment in which they developed –
i.a. their diet – during the 2.5 million years of the Paleolithic era and (2) that our organism is
not adapted to cereals and dairy products, food that appeared much more recently in our
diet, since 6,000 to 10,000 years. Moreover, recent studies have demonstrated risks
associated with consumption of refined sugars and processed foods (Willett and Stampfer,
2003).
In this master thesis, we designed an agricultural system that produces balanced food
baskets in an agroecological way.
With this objective in mind, we first analysed current knowledge in human nutrition and we
developed a database on food nutrition for developing these balanced food baskets. They
supply all the food necessary for an average person, all year long. Three baskets have been
differentiated: (1) one basket adapted from the current consumption patterns of Belgians, (2)
one basket based on Houlbert (2008) (inspired from the paleolithic diet), and (3) one basket
based on a strict paleolithic diet. The baskets present similar energy and protein levels –
respectively 2,100 kcal/day and 15% or more of total energy supply – needed for an average
individual. The quantities considered for the different food categories vary a lot with the
baskets considered. Among others, the quantity of vegetables, fruits, and oleaginous
products is respectively twice and four times as big for the ‘Houlbert-based’ and the
Paleolithic diet-based” baskets, compared to the “Belgian’s habits-based” basket. A detailed
nutritional analysis was also performed to evaluate and compare the different baskets. It
showed fibers, simple sugars and saturated fat levels much more adequate for the
“Houlbert-based” and “Paleolithic diet-based” baskets, according to the Belgian official
nutrition recommendations. The content of macronutrients of the three baskets is
comparable.

2. The baskets have then been translated in quantities of raw matter in order to proceed to the
following step: the calculation of the surfaces needed for the production of the baskets in an
agroecological way. In this purpose, each food product has been associated with a
production unit; plant production has been dimensioned through representative yield values
in organic agriculture collected in literature, and each livestock production has been modeled
on the basis of real agroecological farms. The main criterion for the choice of those farms
was a high rate of self-sufficiency of livestock productions through a maximum use of grass.
Traditional orchards were also integrated in pastures, organic monogastric productions have
been organized as free-range activities, and relatively high slaughtering ages have been
considered for all livestock categories. Rations have been developed for monogastrics to
optimize the use of by-products and the feeding self-sufficiency of the system. The surfaces
needed to produce each food were sum up for each of the “Belgian habits-based”, the
“Houlbert-based”, and the “Paleolithic diet-based” baskets. The results were respectively 25,
23.5, and 27 ares per basket per year. These surfaces are largely used for animal
productions. In comparison, 20 ares per inhabitant are available in Wallonia.
The flows of inputs and outputs between the production units and their environment have
been calculated. This included the farmyard manure, the litter, and the by-products of food
processing.
One specific case of the modeled production system has been designed and optimized for
the Graux Estate. This Estate is performing an agroecological transition. It closely associates
a large mixed farm with several micro-farms specialized in intensive productions such as
market gardening, dairy goat cheese or monogastric productions. In this case study, inputs
quantities have been minimized and the flows of matter between fictive micro-farms and the
Estate have been dimensioned. The Paleolithic diet based baskets have been chosen as the
basis of the calculations, and the total amount of baskets that can be produced on the Estate
(83 hectares of Utilized Agricultural Area) is 305 individual rations. That means that 305
consumers/citizens can be fed on this surface. This result considers an organic and
agroecological production system almost totally self-sufficient.
The main output of this master thesis work is a programmable spreadsheet that can facilitate
the design of systems aiming at producing such baskets in an agroecological way. Different
scenarios can be simulated through the choice of diet, the type of food, and other agronomic
parameters. The simulation can concern only one type of production or a whole system. The
result of the simulation is the surface needed for each crop, the amounts of livestock, the
inputs necessary for that production, and the quantities of by-products generated.
This work is characterized by a system approach gathering agronomy and nutrition. A
methodology based on the data available was set as the work progressed. Also, a significant
effort was devoted to constitute a consistent database on yields, food nutritional
characteristics and processing coefficients.
Further work should be provided for defining more precisely the individual micro-farms. The
labour units required for the productions considered as well as their profitability should be
calculated to better characterize the system. Those criteria, as well as the agronomic
constraints could also be the basis for the development of a food basket that would optimize
the system and eventually minimize the surface needed.
References

3. Cordain, Loren, et al. “Origins and evolution of the Western diet: health implications for the
21st century”. The American Journal of Clinical Nutrition 81 (2005): 341-354.
Eaton S. B., and M. Konner. “Paleolithic nutrition: A consideration of its nature and current
implications.” New England Journal of Medicine 312 (1985): 283-289.
Houlbert, A. La meilleure façon de manger. 1st Edition. Edited par Thierry Souccar Editions.
Vergèze, FR: Marabout, 2008.
Konner M. and S. Eaton. Paleolithic Nutrition, Twenty-Five Years Later. Nutrition in Clinical
Practice 25, 6 (2010): 594-602.
Willett, Walter C., et Meir J. Stampfer. «Rebuilding the food pyramid» Scientific American
(2003): 64-71.