Impact of Dietary Changes on Health and the Environment

October 25, 2021

As the title of an August 2021 study published in the journal Nature Food states, “Small targeted dietary changes can yield substantial gains for human health and the environment.”

In other words, if every American replaced a few of his or her favorite foods — especially conventionally grown beef and processed meats like hot dogs — with other choices, such as lentils and vegetables, we’d able to make significant positive changes not only for our local ecosystems, the environment and climate change, but for our well-being too.

Study Findings

The landmark Nature Food study mentioned above, which was carried over seven-year period by a research team mostly from the University of Michigan, had the goal of identifying environmentally sustainable foods that also help promote human health.

Researchers looked at both nutritional health-based indicators of many popular foods as well as 18 environmental indicators to evaluate how different foods stacked up in terms of their overall value.

The “Health Nutritional Index” was used to measure health effects of different foods, specifically how many minutes of healthy life would be gained or lost per day by including one serving of these foods in one’s diet. Approximately 5,853 foods that are typically included in the American diet, ranging from bananas and carrots to cold cuts and coffee, were evaluated in the study.

The health effects of eating different foods were found to range from 74 minutes of life lost per day to 80 minutes gained.

The analysis indicated that substituting just 10% of daily calories from beef and processed meats (such as hot dogs, some cold cuts and salami) for fruits, vegetables, nuts, legumes and certain seafoods could offer substantial health improvements for the average American. These types of substitution were found to increase healthy minutes of life by an estimated 48 minutes per person per day.

Decreasing beef and processed meats in one’s diet was also found to have 33% less of a carbon footprint.

Benefits of Dietary Changes on Health and Environment

One of the lead researchers involved in the aforementioned study explained to Mind Body Green that this study was unique because it measured both the health impacts of foods and their environmental toll due to the effects of the food’s life cycle. This includes various stages of producing, shipping and disposing of foods, including production, processing, manufacturing, preparation/cooking, consumption and waste.

Overall, many foods that are considered to be healthiest for us, for like most vegetables, fruits, nuts, seeds and whole grains, were also found to be better for the environment.

Replacing even a few of the worst offenders with foods that are better for health and the planet can have big payoffs, such as contributing to less of a carbon footprint, saving resources like land and water, and improving health markers related to a “good-quality and longer, disease-free life expectancy.”

For example, many studies have found that people who eat diets high in processed meat are more likely to develop certain health conditions, including some types of cancers and heart disease. On the other hand, people who eat mostly plant-based diets tend to benefit from improved cardiovascular health and immune function.

Some foods were found to contribute to environmental hazards and even climate change more than others. Environmental factors that were evaluated in the study included:

Ozone depletion
Particulate matter emitted during transportation
Land use and deforestation
Water use

The foods that scored the worst from an environmental perspective were processed meats, red meat including beef, shrimp, pork, lamb and farm-raised fish.

Why? These foods use a lot of resources, such as land and water, to produce — plus raising cattle in factory farms also releases a high amount of greenhouse gases, such as methane, CO2 and nitrous oxide, which are believed to contribute to global warming.

Something that came as a surprise to researchers was the high global warming impact that some plant foods had, specifically greenhouse-raised vegetables. Greenhouse crops may be healthy additions to our diets, but they can be difficult to produce, making them less sustainable than crops grown outdoors.

How to Make Small, Healthy Dietary Changes

To sum up the study’s findings: Experts recommend eating a good deal of plants and little ultra-processed foods, especially processed meats. Consumer fewer animal products and more in-season vegetables, fruits and plant-based proteins seems to be helpful in myriad ways.

As mentioned above, this study investigated the effects of thousands of foods, but 167 were considered to be “the most popular foods in America.” Each food was color-coded depending on its health and environmental impact, either given a green, orange or red score.

Green foods, which should ideally account for the majority of your daily calories, include:

Field-grown vegetables (grown outdoors rather than in greenhouses)
Field-grown fruits
Legumes, beans and pulses
Nuts and seeds
Most whole grains

Orange foods, which should be eaten in moderation, include:

Dairy products, including milk, yogurt and cheese
Low-environmental-impact seafood (some wild-caught fish and mollusks)
Poultry (pasture-raised is best)

Red foods, which should be limited, include:

Processed meats
Red meat raised on factory farms
Pork
Lamb
Sugary drinks
Other processed and “junk foods” like pizza, ice cream, etc.

Risks and Side Effects

While this study encourages people to eat more of a plant-based, seasonal and locally grown diet, some researchers have pointed out that recommendations to reduce meat intake don’t take into account alternative growing practices that can actually benefit the planet.

These include practices like regenerative farming/agriculture and sustainable aquaculture, which produce meat and seafood in a very different way than factory farms or greenhouses. Regenerative agriculture describes farming and grazing practices that, among other benefits, reverse climate change by rebuilding topsoil. Many experts believe that this type of farming model may be one solution to reversing global warming and the climate crisis.

If you are going to include a good amount of red meat and other animal products in your diet, make an effort to seek out foods that are sourced from grass-fed, pasture-raised and wild-caught animals, ideally in a way that supports regenerative agriculture. Opting for non-GMO and organically grown foods (including veggies and fruits grown outdoors) can also benefit the planet and may mean that you consume more nutrient-rich foods, too.

Conclusion

A 2021 landmark study spent seven years investigating the environmental and health impact of over 5,800 foods.
Researchers pinpointed which foods could increase healthy minutes of life and which could decrease quality of life and health markers.
Foods were classified into three color zones depending on their combined impact: green, yellow and red.
Foods with the best nutritional and environmental performances were predominantly nuts, fruits, field-grown vegetables, legumes, whole grains and some seafood.
Foods with the worst scores to limit or avoid include conventionally produced beef, pork, lamb, processed meats and greenhouse-grown vegetables.