A study has revealed that the average American consumer wasted nearly half a kilogram of food every day over a seven year period.

The work was published in the open-access journal PLOS ONE by Zach Conrad from the US Department of Agriculture and his colleagues. It looked at the consumer habits of Americans between 2007 and 2014.

Growing this wasted food used 30 million acres of cropland, 4.2 trillion gallons of irrigation water, 1.8 billion pounds of nitrogen fertiliser and 780 million pounds of pesticides.

Maintaining the environment while also improving diet quality is an important and challenging global issue. Previous research has examined the relationship between diet and environmental sustainability, but food waste has not yet been considered as a factor.

To investigate the impact of diet quality on food waste and environmental sustainability, Conrad and colleagues collected data on food intake and diet quality from the Healthy Eating Index-2015 as well as data on food waste.

Using a biophysical simulation model they were able to estimate the amount of cropland used to produce wasted food. Data from various US Government sources also allowed the researchers to estimate the amount of agricultural amendments such as irrigation water, pesticides and fertilisers used to produce uneaten food.

 Higher quality diets with more fruits and vegetables were associated with more food waste, but used less cropland than lower quality diets, while simultaneously wasting more water and pesticide resources.

These findings indicate that simultaneous efforts to improve diet quality and reduce food waste are needed. The authors suggest that educating consumers on how to prepare and store fruits and vegetables is one practical method to help reduce food waste.

Dr Conrad and his colleagues concluded that efforts to improve diet quality and reduce food waste “may be critical”. 

The study said: “Practically, increasing consumers’ knowledge about how to prepare and store fruits and vegetables will be an essential component to reducing food waste.

“A number of important efforts have been proposed or are underway to reduce and repurpose food waste at the individual and institutional levels, yet further research is needed to better understand the comparative effectiveness of these efforts.”