Every diet has some environmental impacts, often much bigger than they seem. To calculate them, the Sustainable Meat Project developed the so called “Environmental Hourglass“, which also became the symbol of its work. But what is that, exactly, and how is it constructed?

Many Italian and international publications support the concept that it is preferable to follow a well-balanced diet both for its health-promoting effects and for the recent attention paid towards the environment. It is a well-known fact that foods based on animal protein generally impact more per kilogram than those obtained from plants, but the classification and the comparison per unit mass is not significant since the nutritional intake of food differs and because a healthy diet should be based on the balanced consumption of all available foods.

The Italian publication of the Double Pyramid developed by the Barilla Centre for Food & Nutrition (BCFN) in 2010 is worth mentioning as it provides an annual reorganization of available literature accompanied by a graphical representation. The traditional food pyramid, which illustrates the weekly amounts of food recommended for a well-balanced diet, has been juxtaposed by an inverted pyramid that shows the environmental impacts associated with each kilogram of these foods; the foods with a high environmental impact are at the top of the environmental pyramid while those with a low environmental impact are placed at the bottom. Graphically you get an inverted pyramid, which shows how the foods with the greatest environmental impact are those that should be consumed less for a well-balanced diet.

However, a direct comparison, which is extremely clear when using unit values, becomes much less clear when correlated with a correct weekly diet and recommended portions. When graphically representing this concept starting from the recommended weekly consumption proposed in the nutritional guidelines and multiplying them by the average environmental impacts of the various food categories, one obtains an innovative graphical representation that resembles a hourglass. The first edition of this representation was published in a book on the sustainability of branded beef in 2013 by Coop Italy: the hourglass, whose purpose was to propose a different interpretation of the relationship between diet and environmental impact, was reviewed and updated in the Sustainable Meat Project.

The most important aspect that emerges from this representation is that, in a balanced weekly diet, the environmental impact of foods rich inproteins (meat, fish, eggs, legumes, cured meats) is comparable with the impact generated by foods of vegetable origin (fruit, vegetables). In fact, if consumed in the right amounts, the various food categories have a very similar “environmental burden” which is evenly distributed along the hourglass. Therefore, it is reasonable to say that a balanced diet is not only beneficial to the health, but also to the environment.

Conceptually the construction of the hourglass is quite simple: one must multiply the environmental impact (per kg) of foods by the amount consumed in a week, thus obtaining the environmental impact. The criticality of the calculation depends on the data, relating to both the impact and quantity of food, that are selected. For example, people’s fruit preferences can vary greatly (from pineapples to apple) and their relative environmental impacts vary accordingly. The same applies to the amount of food consumed, which cannot be accounted for with accuracy, since people’s choices can differ greatly even if they are part of a balanced diet.

For these reasons, the hourglass was created considering various types of foods with the awareness that the representation presented in our report, “The sustainability of meat and cured meats in Italy”, is not the only one as there are countless combinations of consumption frequencies and favourite foods.

See more about the Environmental Hourglass in the two minutes video below.