At the same time that global warming is making news, a study suggests that eating more fruits, vegetables and nuts and less meat and alcohol — with fewer calories — can reduce greenhouse gas emission by almost 20 percent, compared to the average diet. Many of the dietary patterns identified as environmentally healthy align with AICR’s recommendations for cancer prevention.
The study, published in the American Journal of Clinical Nutrition, is one of the first that takes into account foods nutrition along with its environmental impact.
Last month, the Food and Agriculture Organization (FAO) released estimates showing that greenhouse gas emissions from agriculture was on the rise.
This study used greenhouse gas emissions related to farming and production as a measure of a food’s environmental impact. That includes methane produced by cows and fertilizers applied to crops.
For the study, researchers analyzed the diets of almost 2,000 French adults who were part of a nationally representative diet survey. Researchers categorized the foods into groups, calculating how its nutrients and calories contributed to a person’s overall daily diet. They also looked at how much the foods cost.
There were 391 foods that covered two-thirds of people’s daily calories. A company assigned how much greenhouse gas emissions each of these foods produced. Then the authors categorized the diets into three groups, relative to the average: high nutrients, lower carbon and more sustainable, which took into account the other two groups.
When compared to the average, approximately a fifth of the participants were eating a highly nutritious diet with a low carbon footprint. For men and women, the sustainable diets had 19 percent and 17 lower greenhouse gas emissions, respectively.
Men eating the sustainable diets were consuming 20 percent more of their calories from plant foods, including fruits, vegetables and nuts, compared to the average consumer. Women in the sustainable diets were eating 15 percent more of their calories from plant foods.
The sustainable consumers were also drinking less soda and alcohol, while eating less beef, pork, chicken, eggs and deli meats compared to the average French person’s diet. They were also eating less calories overall: with men eating 8 percent fewer than the average and women 10 percent less.
In this study, the most nutritious diet was not the most sustainable. Yet the top factors driving the sustainable diet were consuming fewer calories and eating less energy-dense foods.
Energy-density is a measure of how many calories are in each bite. Foods that are low in energy density include fruits and vegetables, which contain numerous compounds studied for their cancer-fighting properties. AICR recommends eating a diet low in energy density to help with weight control. Staying a healthy weight can reduce the risk of eight cancers.
The study was funded by the French National Research Agency under the OCAD and the French Environment and Energy Management Agency.