Healthier people mean not only less disease but also reduced greenhouse gas emissions from health care. Changing your diet, therefore, could be a way to fight climate change.
A new study in Climatic Change considers the potential effects of healthier model diets for the United States.
“People have looked at what effect diets have both on climate and on health, but they’ve never examined the potential to mitigate climate change through the food system and the health care system together,” says study director David Cleveland, a research professor in the University of California, Santa Barbara’s environmental studies program and geography department.
The food system contributes about 30 percent of total US greenhouse gas emissions, with the largest proportion coming from animal-based food. In addition, the poor quality of the standard US diet—including high levels of red and processed meat and low levels of fruits and vegetables—is a major factor in a number of preventable diseases.
The US spends $3 trillion on health care every year—18 percent of the gross domestic product—much of it allocated to diseases associated with poor diets.
3 example diets
Cleveland and colleagues first used data from published meta-analyses that examined the effect of foods on diseases. Then, using life-cycle assessment data for the foods that changed in the healthier model diets, they analyzed the effects of the diets on greenhouse gas emissions for the food system.
For the health care system, the researchers estimated the change in risk of diabetes, colorectal cancer, and coronary heart disease due to the healthier diets and the subsequent effect on both health care costs and greenhouse gas emissions.
To create healthier model diets, the researchers altered the standard 2,000-calorie-a-day US diet, changing the sources of about half of those calories. The different model diets progressively reduced the amount of red and processed meats, with the most stringent diet eliminating them completely. Fruit and vegetable intake doubled, and peas and beans increased to replace the meat protein removed. Whole grains partially replaced refined grains.
Added sugar, which Cleveland notes is a known health risk, was not reduced. Neither was dairy, eggs, fish, or non-red meat.
“This means our estimates are probably very conservative, both in terms of health and climate change implications,” Cleveland says. “Just changing half of the diet and including only some of the diseases associated with diets, we found a huge effect.
“Food has a tremendous impact on the environment,” he adds. “That means that there is enormous potential for our food choices to have positive effects on our environment as well on our health and our health care costs.”
That is exactly what the scientists found. The adoption of healthier model diets reduced the relative risk of coronary heart disease, colorectal cancer, and type 2 diabetes by 20 to 40 percent. Health care costs went down by $77 billion to $93 billion annually and direct greenhouse gas emissions dropped by 222 kilograms to 826 kilograms per person per year.
“In the third diet—which contained no red or processed meats—there was a savings of $95 billion out of the total annual cost of $230 billion for those three diseases,” Cleveland explains.
“That’s not huge compared to the $3 trillion total in health care costs, but it’s a start. Results like these can also help motivate individual and policy changes.”
In terms of climate policy, the healthier diets could contribute up to 23 percent of the US Climate Action Plan goal to reduce net greenhouse gas emissions 17 percent below 2005 levels by 2020, Cleveland says.
Further, the diets could generate up to 134 percent of California’s goal of reaching 1990 emission levels by 2020.
According to Cleveland, the findings add weight to the conclusion of several other recent studies: Diet change must be part of successful climate change mitigation policies, and climate change mitigation must be part of policies to improve the food system.
Coauthors of the study are from UC Santa Barbara, Lund University, and Oxford University.
Source: UC Santa Barbara