In a study, the ifeu (Institute for Energy and Environmental Research Heidelberg) examined the effects of various factors on the carbon footprint of approximately 200 foods. This varies significantly depending on origin, degree of processing, and packaging. For tomatoes, for example, the carbon footprint (in kilograms of CO2 equivalent per kg of food, or kg CO2 for short) is:

• 0.8
• from Germany in season 0.3
• from Southern Europe, open field 0.4
• from organic farming 1.1
• cherry tomatoes 0.9
• from Germany, heated greenhouse 2.9
• passata in composite carton 1.6
• passata in a can 1.8
• passata in glass jars 1.9
• Tomato paste 4.3

In addition to the carbon footprint, ifeu also included the consumption of important resources in the study. According to the study, one kilogram of fresh tomatoes has an average

• phosphate footprint of 2 g phosphate rock equivalent
• Land footprint of 0.1 m²·a Natural land use
• Water footprint of 1,000 L water equivalent
• energy requirement of 1.5 kWh primary energy equivalent

This overview shows significant differences in the carbon footprint. Nevertheless, it should be noted here that the production of a tomato generally generates less greenhouse gases than that of a beef steak (average 13.6 kg CO2).

Fresh, unpackaged carrots and white cabbage have a carbon footprint of just 0.1 kg CO2, which is the lowest value of all. This value is closely followed by most local, fresh, and seasonally purchased fruits and vegetables. Plant-based milk products consume significantly less CO2 than similar foods made from cow's, sheep's, or goat's milk. However, one drawback of almond and soy milk is their high water consumption.

Bread and other grain products, such as pasta or bulgur, score well in terms of CO2 balance. In the case of bread, however, the chosen topping can quickly worsen the balance considerably. Plant-based protein sources, such as lentils or nuts, are generally better than animal-based ones. The results of the complete ifeu study can be found in the list of links.

The simplest solution for us consumers would be if the specific amount of climate-damaging gases emitted per kilogram were simply stated on the product itself. Perhaps similar to the Nutri Score for nutritional values, with a traffic light system. However, using the example of tomatoes, it quickly becomes clear that this would be too time-consuming and expensive for the countless food products on German supermarket shelves. Therefore, the average CO₂ consumption is usually assumed.

The organization Eaternity develops solutions for the food industry to accurately and efficiently measure the ecological footprint of food. It has divided almost 500 foods into categories according to their CO₂ footprint and compiled them on a clear poster. The unit of measurement chosen was the amount of CO₂ in grams that corresponds to one-third of the daily requirement. The posters are divided into a total of seven food groups, e.g., meat and meat substitutes, spices, herbs, and vinegar.

These overviews clearly show, among other things, that the carbon footprint of animal-based foods is generally worse than that of plant-based foods. Transport also plays an important role. Long distances, especially when covered by plane, significantly increase CO₂ consumption. Unprocessed and unpackaged foods, on the other hand, generally have a good carbon footprint.

Identifying sustainable foods is more complex than it appears at first glance. Meat tends to be more harmful to the climate than most plant-based (substitute) products. A pea-based burger patty consumes 1.8 kg of CO2, while a beef patty consumes 9.0 kg of CO2. Surprisingly, many organic products have a higher carbon footprint than conventionally grown products. However, this is mainly because more land is needed for cultivation. The complete study can be found in the list of links.

The bottom line is that it remains difficult for consumers to obtain a concrete overview of their carbon footprint in the area of nutrition. Our environmental tip is intended to provide suggestions and point out sources of information.