Sustainable Diets Are Healthy

How can you benefit your health—and the planet’s health—at the very same time?

Over the past several decades there’s been increasing rates of obesity, cancers, type 2 diabetes, and heart disease. This has come at the same time as the rise in processed (think: less natural) foods that are high in calories, sugar, and salt. And, both of these also happen to be occurring as greenhouse gas emissions, water, and land use have been increasing (including for food production). 

Overall, what we’re seeing is a rise in chronic disease, processed food consumption, and environmental degradation.

One of the underlying connections between these three things is what we eat. How we nourish our bodies impacts our health, and how that food is produced is a major driver of environmental impacts.

A recent study published in the journal The Lancet Planetary Health looked deeper into the connections between what we eat, our health, and the planet’s health. The study authors say, “evidence indicates that the declining health of the planet and humans can be mitigated by altering unsustainable diets and food systems, resulting in co-benefits.”

How can choosing a different diet improve our health and the health of nature?

The many benefits of eating more sustainably

Researchers found that eating styles that are linked with higher cancer and death from any cause rates are also linked to foods that emit more greenhouse gases and need more land for production. In other words, you can improve your nutrition, lower your health risks, and reduce your environmental impact all at the same time!

In this study, the researchers estimated that if everyone ate a more sustainable diet, over 20 years the risk of death could decrease by up to 63%, plus up to 39% of cancers could be prevented. At the same time, food-related greenhouse gas emissions can be reduced by up to 50% and land use by up to 62%.

These all show a positive impact and significant benefits of eating more sustainably.

How food production impacts Mother Nature

A lot goes into producing food. And not all food gives us the same nutrients for the same environmental impact.

The nutrients in our day-to-day foods impact our personal health. In the same way, the food choices we make impacts the Earth’s health. Before we can eat our food, it has to be farmed. In order to farm food, it needs to use land, freshwater, and creates greenhous gases. 

Currently, agriculture produces 25% of the human-made greenhouse emissions, consumes about 70% of our freshwater, and uses over 33% of cultivable land. 

As you can see, changing our food choices can make a big difference to nature.

An ideal situation would be to eat foods that provide us with the vitamins, minerals, and other essential nutrients, while at the same time producing less greenhouse gases and use less land and water.

There is a special diet that’s been developed to be both healthy and more environmentally sustainable. It’s call the “EAT-Lancet diet.”

Of course, even eating a little bit more closely to the EAT-Lancet diet may help reduce risks of death, cancer, and reduce greenhouse gases and land use, even if it’s by a smaller amount.

What is the EAT-Lancet (or “planetary health” ) diet?

The researchers say, “Our findings, along with other studies, including the EAT-Lancet report, suggest that co-benefits to human health and the environment could be achieved by adopting diets that consider both nutritional quality and planetary impact, such as the EAT-Lancet diet.” 

The EAT-Lancet or “planetary health” diet is pretty simple and allows for a lot of freedom. In fact, you don’t need to give up anything you love if you don’t want to!

The EAT-Lancet recommends that:

  • half of your food (by volume) intake consist of fruits, non-starchy vegetables, and nuts
  • the other half is whole grains, beans and legumes, unsaturated fats, starchy vegetables, and small amouns of meat, dairy, and added sugars

These are very broad guidelines, so you can customize these in any way that works for you. Some examples of diets that meet these recommendations include the Mediterranean diet, pescatarian diet, and vegetarian diet.

  • Add fruits and non-starchy vegetables to every meal by adding berries to your breakfast, tomatoes to your lunch, and a side salad to your dinner
  • For snacks, try nuts, or a banana, apple, or orange.
  • Consider some plant-based swaps, like avocado instead of butter or mayo, nut butter instead of cream cheese, or vegetable or mushrom broth instead of chicken or beef broth
  • Enjoy more whole grains like whole wheat bread and pasta, brown or wild rice, or quinoa
  • Try more beans and legumes by swapping out half of the ground meat for lentils in tomato sauce, soup, or chili, or swapping out chicken for chickpeas in curries and stir fries
  • Aim to reduce your meat intake by as little as one-third (so, if you eat meat 6 days/week, aim to enjoy it 4 days/week)

Reference:

Laine, J. E., Huybrechts, I., Gunter, M. J., Ferrari, P., Weiderpass, E., Tsilidis, K., Aune, D., Schulze, M. B., Bergmann, M., Temme, E., Boer, J., Agnoli, C., Ericson, U., Stubbendorff, A., Ibsen, D. B., Dahm, C. C., Deschasaux, M., Touvier, M., Kesse-Guyot, E., Sánchez Pérez, M. J., … Vineis, P. (2021). Co-benefits from sustainable dietary shifts for population and environmental health: an assessment from a large European cohort study. The Lancet. Planetary health, 5(11), e786–e796. https://doi.org/10.1016/S2542-5196(21)00250-3

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8581185/

https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(21)00250-3/fulltext

Backgrounder articles:

About the study:

  • This study is part of the European Prospective Investigation into Cancer and Nutrition (EPIC) study.
  • Researchers wanted to look for “co-benefits” of both nutritional health and environmental health standards in a more holistic way. This includes the impacts of shifting toward diets that are more sustainable that can “improve population and planetary health.”
  • The researchers followed 443,991 participants for about 14 years (these big numbers make this a strong study), asking them to report what they ate. They also cross-checked the participants’ medical records for cancer diagnoses, other diseases, and death. Then, they took the reported food intake, split them into 4 groups (“quartiles” based on how closely they ate compared to the EAT-Lancet diet), and estimated the greenhouse gas emissions and land use for each quartile. They looked at all of these numbers and estimated impacts to health and the environment if more people ate a diet that was closer to the EAT-Lancet diet. 
  • They found that, if people ate an EAT-Lancet diet over 20 years, “all-cause mortality and all cancers could be substantially reduced, together with reductions in greenhouse gas emissions and land use.”
  • Conclusion: “Our results indicate that shifts towards universally sustainable diets could lead to co-benefits, such as minimising diet-related greenhouse gas emissions and land use, reducing the environmental footprint, aiding in climate change mitigation, and improving population health.”
  • Every study has limitations (there is no single perfect study, so see the study strength I noted in the last bullet below), that’s why I give more weight to stronger studies, and more weight to evidence that is independently corroborated in multiple strong studies. For this study, the participants reported their own food intake, which makes it easier to get information from hundreds of thousands of people (good!), but it isn’t the most accurate measure of real food intake for each individual person (not so good!). This study was done in several countries in Europe, so that means the greenhouse gas and land use estimates are likely more accurate for European food than the would be elsewhere. Also, this study didn’t take into account the entire food system, so future studies could look in more detail at the processes, infrastructure, institutions, waste, etc. when it comes to the environmental impact of food, including the impacts of production, processing, distribution, preparation, and consumption of food. Another thing to consider is that there are important factors that go into how people choose the foods they do (e.g., social, ethical, economic, cultural, and food safety) and these weren’t included in this particular study. There are other environmental impacts that weren’t included (e.g., water use, acidification, loss of biodiversity, etc.). Despite all of these, this study included hundreds of thousands of people and lasted 14 years, and that’s what makes it a pretty strong study. More research is always recommended to dive even deeper into these issues and answer additional questions. ?
  • Because this was an observational study, we can’t say that eating closer to an EAT-Lancet diet “prevents” death and cancer, just that it appears to reduce risk or it’s associated with a lower risk over time (correlation does not equal causation). Here’s a blog post I wrote on this concept: https://leesaklich.com/health-research/correlation-does-not-equal-causation/
  • Study strength: 5/7 according to this chart (this is a prospective cohort study): https://www.compoundchem.com/2015/04/09/scientific-evidence/