Is it better to be a locavore or perhaps a vegetarian in order to improve your health and the environment? Should we be aware of the impact that our food purchases have on climate change? Entering the debate is a new study out of the University of Michigan (UM) in the United States that has identified simple food choices that people can make to simultaneously improve their health and reduce their environmental footprint.
The UM study was conducted over seven years by a group of experts in food sustainability, environmental life cycle assessment, epidemiology and environmental health, and nutrition. They pulled together pieces of this complex, multidimensional puzzle and extracted the health and environmental impacts of thousands of foods. As human and environmental health are intertwined, their results could bring relief, providing a clearer picture of how to compare foods and make mindful decisions that lead to greater longevity on a healthier planet.
Food Choices Impact Your Lifespan and the Environment
The researchers went beyond counting calories or carbohydrates—or comparing whole foods to processed foods—and categorized and analyzed food choices based on composition to arrive at a calculation of each food item’s net benefits to, or impacts on, the human body. Specifically for nutrition, the study’s authors developed a Health Nutritional Index (HENI) for more than 5,800 foods commonly consumed in American diets. Using their index, they meticulously quantified marginal health effects in terms of minutes of healthy life gained, or lost, from eating certain foods. Individual foods and mixed dishes ranged from 74 minutes lost to 80 minutes gained per serving.
Assessment of the American hot dog provides an example of how the nutritional numbers were crunched by the researchers into minutes of life lost or gained. First, they found that, on average, 0.45 minutes of life are lost per gram of any processed meat consumed in the U.S. They then used previously developed food profiles to further weigh the good and bad aspects of a hot dog.
Individual foods and mixed dishes ranged from 74 minutes lost to 80 minutes gained per serving. For example, according to the study, eating one hot dog may subtract 36 healthy minutes from your life.
A hot dog consists of 61 grams of processed meat, resulting in 27 minutes of healthy life lost due to the amount of its processed meat content. Other risk factors, such as the sodium and trans fatty acid content of the hot dog were counterbalanced somewhat by the benefits of the polyunsaturated fats and fiber that were present. With all calculations finalized, eating a hot dog resulted in a negative value of 36 minutes of healthy life lost.
The Environmental Impact of Eating
Regarding the environmental impact of food production, researchers found striking variations both within and between animal-based and plant-based foods. Beef, for instance, had the largest carbon footprint across its entire life cycle, coming in twice as high as pork or lamb and four times higher than poultry and dairy.
The study also showed that when it comes to measuring sustainability, it is not sufficient to consider the amount of greenhouse gases emitted as the sole indicator of a food’s so-called carbon footprint. The water footprint of food production is also an important factor. Taking a look at production methods such as drip irrigation and the reuse of gray water provides a more accurate accounting of the sustainability of a food’s production methods. However, the study did not take into account the emergence and increase in regenerative farming practices, perhaps because the practice is too new or small in scale to provide adequate data. One could surmise that some of the foods that scored worse on environmental impacts might have ranked better if grown with regenerative practices.
Simplifying Personal Food Choices
The researchers compared food scores from their HENI with scores from health indices based on the What We Eat in America database of the National Health and Nutrition Examination Survey, as well as environmental metrics drawn from IMPACT World+, an assessment method that determines the environmental impact of food production and processing from manufacturing to cooking to waste. The researchers then created a color-coded chart identifying each food item as green, yellow, or red (see chart above). Like a traffic light, green means go and indicates both beneficial health effects and a low environmental impact for a certain food. One obvious conclusion would be that “green” foods should be increased in the diet, while “red” foods should be reduced.
While it is clear that processed meats and red meats in general fall furthest into the danger zones of minutes lost and increased carbon footprint, not everyone needs to become a vegan to meaningfully improve the health of the planet. Simply using the Green, Yellow, and Red color-coded indicators helps people make quick and easy choices between foods that are good-to-go (green) and those to be consumed with caution (yellow).
In terms of human health, the study’s results suggest that cutting out processed meat and reducing sodium consumption across the board provides the largest overall gain in healthy longevity compared with all other food types. The simplest and most effective dietary changes might be to eat less of foods that are high in processed meat—particularly beef, followed by pork and lamb—along with reducing greenhouse-grown vegetables which can be energy-intensive to produce.
Foods that people might consider increasing are the green-coded choices with high beneficial health effects and low environmental impacts such as whole grains, fruits, vegetables, nuts, legumes, and low-environmental-impact fish and seafood.
The Future of Healthy and Environmentally Friendly Food
The researchers noted that using their system will allow people to align their diets with their personal tastes, budgets, and goals for a more sustainable future by making simple swaps within the guidelines. One food choice at a time, individuals can feel that they are making a difference. Small shifts in behavior can be easier to manage, thus encouraging even more changes. An individual’s success using the system may encourage others to make similar changes, adding up to substantial improvements in human and environmental well-being. The study’s results could be part of a movement toward healthier and more sustainable diets, one food at a time.
The authors are hopeful that their food data can be made available and useful to the public through platforms such as a shopping app or grocery store displays. This would allow more individuals to choose more minutes of a healthy life and protect the planet as they plan their next meal.
*Julie Peterson is a freelance journalist based in the Midwest region of the U.S. who has written hundreds of articles on natural approaches to health, environmental issues, and sustainable living.