For a sustainable diet, it’s not enough to just avoid red meat. A new study finds that the families with the highest carbon footprints are those that frequently eat out and consume a lot of alcohol and sweets. 

To come to this conclusion, researchers from the University of Sheffield in the UK and the Research Institute for Humanity and Nature in Kyoto, Japan, analyzed the carbon footprints of the diets of 60,000 households across Japan. 

“All countries are facing challenges in how to shift diets to be healthier and more sustainable,” Christian Reynolds, a co-author of the study and researcher from the Institute of Sustainable Food at the University of Sheffield, said in a news release.

“This evidence from Japan demonstrates that research can help us to identify what to focus on,” he continued. “The same patterns of dietary change in terms of sugar, alcohol and dining out need to be considered in the UK, Australia, the United States and Europe.”

The researchers determined that meat consumption only accounted for 10 percent of the difference between carbon footprints in Japanese homes, while those with high carbon footprints frequently dined out and consumed 2-3 times more sweets and alcohol than those with low footprints. 

This isn’t to suggest, however, that people should start eating red meat freely, with no consideration for the environment. 

“Meat is a high carbon footprint food. Replacing red meat consumption with white meat and vegetables will lower a family’s carbon footprint,” Keiichiro Kanemoto, lead author of the study and associate professor at the Research Institute for Humanity and Nature, said in the release.

Instead, the study suggests that red meat isn’t the only dietary factor consumers should consider. 

“While nearly all households can reduce their (carbon footprint) by eating less meat, higher-(carbon footprint) households are not distinguished by excessive meat consumption relative to other households but rather have higher household (carbon footprint) intensity because of elevated consumption in other areas including restaurants, confectionery and alcohol,” the researchers wrote in the study. 

For households with a higher footprint, for example, they found that dining in restaurants contributed on average 770 kilograms (nearly 1,698 pounds) of greenhouse gases per year while meat contributed just 280 kilograms (617 pounds).

Although the study only focused on Japanese homes, its results apply globally as “Japan’s demographics and dietary patterns are indicative of likely future demographics of many other Western and Asian nations with an older population, urbanized population, smaller household size, increased consumption of hyper-convenience and ultra-processed foods, and decreased adoption of ‘traditional’ diets,” the researchers wrote. 

Additionally, Japan provides a lot of data on household food consumption and demographics, which enabled the researchers to break down and analyze carbon footprints based on things like geographic location and income level. 

“Due to wealth, culture and farming practices, different regions in a country consume food differently,” Reynolds said in the release. 

“Japan alone has some prefectures with more than 10 million people and others with fewer than one million,” he continued. “These regional and income differences in food consumption are also found in the UK, Europe, Australia and the United States.”

Transition to healthier foods

This study reinforces previous research that the healthiest foods are almost always also the least damaging to the environment. And therefore, individuals and their families can truly help mitigate climate change by eating a healthier diet.  

However, it also proves it’s more complicated than encouraging everyone to become a vegan or vegetarian, as people also need to become aware of how much they dine out and how much sugar they eat, among other things. And with less than 11 years left to prevent climate change from causing irreversible damage to the planet, people may need a stronger incentive to change their eating habits.

“If we think of a carbon tax, it might be wiser to target sweets and alcohol if we want a progressive system,” Kanemoto said in the release. 

“If we are serious about reducing our carbon footprints, then our diets must change,” he continued. “Our findings suggest that high carbon footprints are not only a problem for a small number of meat lovers in Japan. It might be better to target less nutritious foods that are excessively consumed in some populations.”