The production of food is responsible for major environmental impacts. Bearing this in mind, it is even worse when food is lost rather than consumed. In Switzerland, 46% of all processing potatoes and 53% of all fresh potatoes are lost on their way from field to fork. Our study therefore compares the environmental impacts of losses of fresh potatoes with those of French fries. With the aid of a Life Cycle Assessment, we assessed the impact categories “demand for nonrenewable energy resources”, “global warming potential”, “human toxicity”, “terrestrial ecotoxicity” and “aquatic ecotoxicity”. Our results show that 1 kg of potatoes consumed as French fries causes 3–5 times more environmental impacts than the same quantity of fresh potatoes, but also that the proportion of impacts relating to losses is considerably lower for French fries (5%–10% vs. 23%–39%). The great majority of processing potato losses occur before the resource-intensive, emission-rich frying processes and therefore the environmental “backpack” carried by each lost potato is still relatively small. Nonetheless, appropriate loss treatment can substantially reduce the environmental impact of potato losses. In the case of French fries, the frying processes and frying oil are the main “hot spots” of environmental impacts, accounting for a considerably higher proportion of damage than potato losses; it is therefore also useful to look at these processes., Sustainability, 8 (12), ISSN:2071-1050