Is a Sustainable Diet a Healthy Diet? Defining and Describing How to Achieve Both
Witiw, Eric. “Sustainable and Healthy Diets”. 2020, PNG file.
By now, I think most of us have been scolded by someone for our consumption of animal products. And the truth is, animal based foods do have a large impact on the environment – but what about everything else? Have you ever wondered how much worse for the planet a burger is than a salad? Or is eating more sustainably always healthy? And what exactly is a healthy diet anyway? This blog post is not an attempt to sway you or tell you what you can and cannot eat, but rather to make you think a bit harder about how to balance nutrition and sustainability.
Defining Sustainability and Health
Sustainability is a big buzzword these days. It means different things to different people- so for the purpose of this post, the definition for sustainable development from the UN Sustainable Development Agenda will be utilized. It is:
“Development that meets the needs of the present without compromising the ability of future generations to meet their own needs”
So considering this and the relationship with our planet, factors such as land use, water consumption and greenhouse gas emissions all become important for future generations to meet their needs with respect to food. Additionally, nutrition is at the forefront when examining the needs of the present and the purpose of food sustainability. The end goal of nutrition is to improve or maintain human health. The World Health Organization (WHO) defines health as:
“A state of complete physical, mental and social well-being and not merely the absence of disease or infirmity”
‘Complete physical, mental and social well-being’. So by definition, we are technically always in pursuit of better health. Food and nutrition both have major impacts on our physical, mental and social well-being and therefore are important to our health. For most of us, food is intended to fulfill the needs of the present, our health. In order to ensure that the future generations are able to do the same, sustainability should be equally as important. Unfortunately, what is most sustainable is not always what provides the best health to most people.
Environmental Impact of Food
You may already know that beef, lamb and dairy (all from larger livestock animals) require a lot of land use compared to other foods. But what is maybe not as well known is the land use required for something like dark chocolate compared to say a food like nuts. In fact, dark chocolate requires more land than some animal based foods under both metrics of measurement. When understanding the sustainability of a diet, looking at land use is necessary because agricultural land use made up 37.431% of total global land use in 2016. How we treat our land is also drastically important because soil is the largest land based carbon reservoir that we have in the world. Organizations such as the U.S. Farmers and Ranchers in Action (USFRA) have highlighted the urgency to restore our farmland as we need to grow more food for a growing population with limited amounts of arable land. With such a large proportion of our land designated for agriculture, proper soil conditions are paramount for not only curbing emissions, but also ensuring long term usage for food production. This means land use or land use change in relation to agriculture is extremely important when considering sustainability.
Greenhouse Gas Emissions
Beef, again, remains atop the list. Other high ranking foods are cheese, lamb and farmed prawns (shrimp). As seen in the chart comparing food emissions across the supply chain, by kg of food produced, the biggest proportion of beef and lamb emissions comes from methane emissions during farming. This is because they are ruminant animals. Ruminant species have an extra section in their stomach that allows them to process fibrous foods that humans and other animals cannot, which then creates methane as a byproduct. A more detailed breakdown of the entire lifecycle of livestock and where emissions occur will be available in a future article, but for now, the important takeaway is that while animal products do skew heavily to greater greenhouse emissions, not all animal based foods are equal. Ruminant animals have a greater emissions output per kg and per 1,000 kilocalories compared to pork and poultry.
When we see a Calorie with a capital ‘C’ on food labels, this is a way of saying kilocalorie. So 1,000 kilocalories in these graphics is equivalent to 1,000 Calories of that food like we would see on a label
Some other Interesting Outcomes:
- Cheese out-emits both pork and poultry under both metrics.
- The differences between animal products generally have a greater net difference of emissions between each other compared to distinctions within other food groups.
- On a per 1,000 kilocalorie basis, coffee out-emits even beef, yet is ranked comparatively lower on a per kg of coffee basis.
- Conversely, cheese finds itself higher on the list on a per kg basis than on a per 1,000 kilocalorie one.
Witiw, Eric. “Coffee vs. Cheese”. 2020, PNG file
Cheese and coffee are interesting because they show the importance of using each dataset as a baseline rather than an outline for building a sustainable diet. These disparities highlight that different food products serve different purposes when considering their emissions; cheese is more calorically dense than an item such as coffee. What you would likely replace cheese with in your diet is not what you might replace coffee with. While eliminating animal products is the single most impactful way to reduce net greenhouse gas emissions based on dietary choices alone, it is not always feasible for everyone. When looking to make a sustainable change in one’s diet, it is often best to look at what a direct replacement for a food item might be. This could be anything from switching from milk to soy milk, cassava to potatoes, or even from one type of meat to another. How to incorporate these sustainability changes with proper, balanced nutrition will be discussed further below.
Freshwater usage gives one final metric to consider long term sustainability of food items. Freshwater is a limited resource in itself, so its consumption is a substantial factor in considering the sustainability of a food.
Maybe the most prominent takeaway is how much freshwater farmed-fish and prawns demand. With as distant as agriculture has become to the average American, seafood production is, perhaps, even more distant. Farmed seafood (obviously) requires water, but the extent to which it is demanded relative to other food is not common knowledge.
Some Other Interesting Outcomes:
- On a per 1,000 kilocalorie basis, tomatoes and cheese outrank many animal based foods such as beef, lamb, poultry and pork
- Rice ranks relatively high on both metrics in terms of freshwater usage
- Nuts rank much higher in terms of water use, relative to the other foods researched despite being comparatively low for both emissions and land use
These datasets also show the importance of understanding the purpose/nutrient density of a food item in terms of freshwater usage. Similar to the emissions data, some food items rank differently based on the unit of measurement. What this means is that no one statistic or data set fully encompasses the environmental impact of a food.
A Healthy Diet
I am not an expert on nutrition, so I decided to ask a friend of mine for some insight who actually does happen to be one. Julie Scott is a Registered Dietician, who works for Summerfield Custom Wellness. When asking for guidance, the first thing Julie emphasized to me was that nutrition is far from a one size fits all science, saying “no one diet or lifestyle fits everyone, and that it really depends on the person.” With that in mind, some good points of reference towards a healthy diet in the U.S. are the USDA MyPlate program and the 2015-2020 Dietary Guidelines for Americans, which she says are “recommendations for the general U.S. population”.
Some key recommendations are to maintain a diet that includes:
- A variety of vegetables from all of the subgroups—dark green, red and orange, legumes (beans and peas), starchy, and other
- Fruits, especially whole fruits – Julie recommends that you “eat the rainbow of both fruits and vegetables!”
- Grains, at least half of which are whole grains
- Fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages
- A variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), nuts, seeds, and soy products
Witiw, Eric. “Healthy Diet Foods.” 2020, PNG file.
Witiw, Eric. “Foods to Avoid.” 2020, PNG file
And to limit:
- Saturated fats and trans fats, added sugars, and sodium
The guidelines also specify that nutritional needs should be met primarily from foods, with an emphasis on consuming nutrient dense foods. Nutrients are chemicals necessary for things like growth, maintenance and energy, that the human body cannot create on its own. This means that they must be consumed in order to be utilized. They are broken down into macronutrients (nutrients needed in large quantities) and micronutrients (nutrients needed in trace quantities).
*Water is a macronutrient in the sense that large quantities need to be consumed, but it does not provide you with energy or contain carbon like the other three do
A healthy diet also includes fiber, which cannot be processed by the human body, but is important for digestion and disease prevention.
It’s also necessary to ensure proper caloric intake in addition to a full nutrient profile. Balancing the calories consumed to physical activity is important in preventing excess weight gain that could lead to obesity and other negative health outcomes.
Challenges Within Sustainable, Healthy Eating
The obvious standout here is within the macronutrient of protein. The dietary guidelines explicitly state that the recommended American diet includes apportioned amounts of “seafood; meats, poultry and eggs; and nuts, seeds and soy products” to provide protein in a given week. The most diverse array of proteins possible includes animal based food products. Even for the recommended vegetarian diet, the guidelines suggest consumption of dairy and eggs and in addition to plant based proteins such as legumes, soy and various nuts. Each protein source also contains a unique set of vitamins and minerals, so further diversifying one’s proteins is nutritionally beneficial. While eliminating animal based foods entirely is the most significant method to improve dietary sustainability, it is not necessarily optimal for human health, at scale. The guidelines recommend nutritional needs be primarily met by foods and therefore supplementing nutrients as a primary source is not promoted as the best choice either. For a deeper dive into sustainable protein sources, check out this article from Cook & Culture on the subject.
It’s important to remember that these guidelines were made to provide a diet that would be both beneficial and realistic for most Americans. A diet devoid of any animal products can still be healthy. But to do so would require an increased aptitude to account for the resulting nutrient deficiencies. Julie highlighted one such challenge here with Vitamin B12, an important micronutrient that is easy to become deficient in when following a vegetarian or vegan diet. It is “only found naturally in animal products. Given that, dairy products can be a good source of B12 for vegetarians (barring any other individual circumstances). And some versions of plant-based milks, nutritional yeast, and cereals are also fortified with B12 and can be a good option for vegans to incorporate.” Unfortunately, these foods are not always as affordable or accessible as their animal alternatives, meaning a healthy version of these diets is not attainable for all people.
Another, maybe less glaring, discrepancy is the differences between some plant based items. Fruits and dark green, red and orange vegetables often have a greater environmental footprint than starchy vegetables. Julie reminded me that “it’s important to eat a variety of fruits and veggies since different fruits and veggies have different nutrition profiles”. So swapping out tomatoes or apples for more potatoes and corn is not recommended either.
In many instances, cane sugar appears to be relatively low in terms of its environmental impact – sometimes appearing even lower than fruits and vegetables. Although added sugar should be limited in a healthy diet, a sustainable diet might involve consuming more added sugar and less meat, dairy, eggs and even produce.
Eating healthy includes consuming a variety of nutrient dense foods. This helps to limit overconsumption of calories while ensuring proper nutrient intake. Fortunately, this is also part of a sustainable diet with one estimate showing that reducing global obesity by 50%, could reduce emissions by 800,000,000 tonnes of CO2e from baseline projections going into 2050. By definition, a sustainable diet “meets the needs of the present”, so eliminating entire food groups does not appear to be sustainable nor healthy, but eating less of them could be both.
So What Should I do?
- Consider eating less beef and lamb
The key word here is less. 2020 has been tough enough, so no need to cancel burgers or ribeye steaks, but ruminant meats have a large environmental impact no matter the metric used. They are a great source of protein and micronutrients such as zinc, B vitamins and iron in a healthy diet. Fortunately, just switching from beef and lamb over to other animal protein sources like pork or chicken has a large net impact. It is not feasible for all people to completely eliminate meat, dairy and eggs, so a more attainable change is the reduction of ruminant meat consumption which allows for a balance between a healthy and sustainable diet.
2. Limit your food waste!
Did you know that up to 40% of all food in the U.S. goes to waste? If it were a country, food wastage would be the third largest greenhouse gas emitter in the world, after China and the U.S. And in America, over 80% of all wasted food occurs at the consumer facing level; groceries, food service, restaurants and households (43% alone occurs here!). Take all of the environmental impacts of food and they are just as much present for the food we don’t get to eat. Julie recommends, “trying to have your pantry and freezer stocked with nutritious staples that will not spoil quickly, and trying to have a plan before you purchase fresh fruits and vegetables”. Although some food waste is inevitable, it does not always have to end up in the trash either. If your food can’t safely be consumed later, try researching alternatives such as local composting or utilization for animal feed. Check out this article for more detailed reduction tips. The opportunities are plentiful and the best part is that you don’t even have to change your dietary choices to start making a huge impact on the environment.
3. Ask for Help!
Over-consumption of calories and nutrient deficiencies can and do occur in the same people. While this might sound counter-intuitive, it’s a testament to the complexities of nutritional science. Fortunately, Julie told me that “if you have questions about your specific dietary circumstances, more and more health insurance providers are beginning to offer a certain number of free visits with a dietitian per year.” With some help, you can “see what foods are best for the environment and your specific lifestyle/goals and then find that sweet spot or overlap”.
Call to Action
Julie summarized the overarching conclusion well, “there needs to be a balance, just like with everything else in our lives. What that balance is going to look like will be different for everyone based on their individual values.” Research has shown that stopping overconsumption is easier to stick to when you don’t have to limit what foods you can consume. This science reinforces the point that to best make long term changes to your diet in relation to consuming proper volumes of nutrient dense foods, you should make adjustments that are accessible to you. Learn what a healthy caloric intake is relative to the nutrients you need and your physical activity, be mindful of your waste, and if you are a human carnivore, try to swap out beef for chicken or pork when possible. As Julie told me, try to “make the smallest change that will have the biggest impact”. This philosophy holds true for both sustainability and nutrition. As daunting as balancing sustainable consumption with healthy eating may seem, start with these three tips and go from there!
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