[MUSIC PLAYING] SPEAKER 1: So what does a sustainable diet look like? Over the next few slides, we will review some guiding principles for choosing foods that are both better for the environment and climate and health. Reducing the consumption of animal products, particularly red and processed meat, is perhaps the first and most impactful step, especially in high income countries, such as the United States. This can be done by replacing animal proteins, especially red and processed meat, with healthy plant-based protein sources. There are many different approaches. For some, it means reducing meat to one to two servings a week. For others, it may mean abstaining altogether. The EAT-Lancet Planetary Health Diet recommends one serving of red meat per week, two servings of poultry, two or more of fish, and one daily serving of dairy plus daily intake of legumes and nuts. The US has a long way to go to get to a minimally healthy diet per the dietary guidelines and are above the mark with meat. Americans are consuming more meat and refined grains than recommended and are not meeting requirements for fruits, vegetables, and dairy. While per capita poultry consumption has increased, the majority of meat consumed is still red meat, including beef, pork, and lamb and nearly a quarter is processed meats, such as hot dogs, bacon, sausages, deli meats, et cetera. The best available estimate of US meat consumption is nearly 6 ounces of total meat a day with red meat and processed meat making up the bulk of that, exceeding the general recommendations. Along with less meat, it's worth mentioning better meat. While the impact on climate is not significantly different or at least limited, there are many other health and environmental consequences to the way animals are raised for food. Choosing smaller portions of meat raised without antibiotics and acknowledging how it's produced can support a healthier food system overall. Given the known health consequences of eating too much red and processed meat, just eating less is a simpler solution then when we come to dairy. Dairy intake is associated with more health benefits, especially for growth in children, and is a significant source of many critical micronutrients including calcium, magnesium, phosphorus, iodine, and zinc. It may also be protective for severe heart disease and all-cause mortality. But dairy has a significant environmental footprint and dairy alternatives are mixed on both sides of the equations. Recommendations for dairy must incorporate these nuances. This slide is a little complicated, but what the study did is look at the environmental impact of dairy compared to beef, poultry, pork, and eggs. What the data in this chart shows is that by most measures, land, water, greenhouse gas and reactive nitrogen, dairy is better than beef, but it's worse than poultry, pork, or eggs. One nuance might be the type of dairy consumed. Dairy products that require large quantities of milk, such as butter, Greek yogurt and hard cheese, have greater environmental impacts than liquid milk alone, as depicted in this whisker plot. The second guiding principle is consuming more foods that come from plants. While eating less meat is critical, health benefits are only realized when more legumes, whole grains, vegetables, and fruits are consumed. Healthy plant-based proteins can adequately replace animal products in most cases. Not all plant-based proteins are created equally. Pulses, or beans in particular, offer huge value in terms of both nutrition and environment. We are eating more legumes in the United States, but still minuscule compared to other proteins. Recently, more plant-based products that look and taste more like meat, often called alternative meats, are coming to the market. Because they have varying ingredients and processing, the health and environmental impacts also vary greatly. The graph on the right demonstrates this with tofu, pulses, and peas having extremely low greenhouse gas impacts per 100 grams of protein, and products or alt meats being generally higher, but also with a much larger range, as shown in the length of the dark orange line. Of note, all plant-based products still have much lower greenhouse gas footprints than beef and dairy. You may have noticed the cell based meat line as well. I don't have time to cover this here, but I will note the huge variation due to production methods and refer you to our CLF research review on the public health impacts of meat alternatives published in 2020. Pulses are a subgroup of legumes used mainly as protein sources in the diet. Common pulses include beans, dry peas, chickpeas, and lentils. Legumes that are used as vegetables, peas and green beans, or for oils, like soybeans or ground nuts, are not considered pulses. Pulses are high in protein, fiber, and many vitamins. They are generally hearty crops and grow easily. They are associated with healthier overall diets, lower BMIs, and lower risk of diabetes and other chronic diseases. There are mixed perspectives on soy, but the overall body of evidence suggests that soy has positive effects on health. Soy foods are rich in nutrients, including B vitamins, fiber, potassium, magnesium, and high-quality protein. Unlike some proteins, soy protein is considered complete, containing all nine essential amino acids in sufficient quantity. In fact, in this chart, the protein quality score of the soy is equivalent to dairy egg whites and beef. Some of the confusion surrounding soy stems from the isoflavones found in soy, which are plant estrogens and thought to mimic estrogen in the body. High levels of estrogen have been linked to an increased risk of breast cancer. However, food sources of soy don't contain enough levels of isoflavones to increase the risk of breast cancer. To add to the complexity, many different types of foods are made from soy ranging from unprocessed foods like tofu and edamame to the ultra processed soy products containing textured soy protein and soy protein isolate. This makes communicating the health impacts of soy more challenging. In terms of environmental impacts, soy production uses less water and resources compared to animal proteins. However, only about 6% of soy ends up as food for humans. Most is grown for animal feed. Deforestation related to soy production in Brazil contributes to about 29% of the country's greenhouse gas emissions. Nuts are nutrition powerhouses with healthy fats, fiber, vitamin E, and some calcium. They do tend to require more water and possibly chemicals to produce, but there are other factors to keep in mind. Tree nuts, for example, may use mostly rainwater and have high yields. Peanuts are actually legumes, not nuts, and are grown in the soil. They have similar low greenhouse gas footprints to other legumes and also fixed nitrogen in the soil. Beyond choosing plant sources of protein, there's strong evidence that a varied diet with plenty of whole grains, colorful vegetables, and fruits is key to disease prevention and overall health. Variety is also of key importance for protecting biodiversity of plants and animals. Dietary diversity or dietary species richness is a measure of food biodiversity and nutritional quality of diets. In terms of biodiversity, species richness has declined dramatically in the past 100 or so years. Today, only 12 plants provide 75% of the world's food. Just rice, maize and wheat contribute 60% of all calories consumed from plants. And in some of these countries, meat intake is very low so the overall biodiversity of the diet is poor leading to nutritional deficiencies, especially in women and children. Grains are often overlooked when talking about plant-based proteins and foods. Corn, soy, and wheat are the most grown, but there are many more used globally and being sold in the United States, such as teff, farro, quinoa, brown rice, and oats. Whole grains, in particular, offer beneficial fiber and vitamins, as well as some protein. Grains can be grown more sustainably by pursuing varietals versus monocultures. And some, such as oats, rye, and barley, can be utilized as cover crops for soil fertility. In fact, choosing whole grains over refined products uses wheat more efficiently, thus making it a more sustainable choice. What about local? In terms of climate, the benefits are small in comparison to changing production and consumption patterns. However, there are other benefits of local purchasing to consider, such as the general use of more sustainable practices on small farms, more variety, and lower use of harmful chemicals and benefits for the food producers and their community. Finally, a quick nod to eating fewer highly-processed foods overall and reducing food waste for health, but also added environmental impact from farm gate to the plate. Processing and transportation influence both a food's health and sustainability. The farther that food moves away from its original source typically the greater the impact. Nutrients are lost or changed along the chain or in some cases, never fully developed, as when produce is harvested before it is fully ripened so that it will withstand transportation and storage. Resources are used for processing and packaging, particularly plastics and chemical preservatives. And many processed foods have added sugars and refined flours and oils of which high consumption is associated with overweight and chronic diseases. A recent study demonstrated that in developing countries, these pre and post farm everything outside of harvest are contributing increasingly more to climate, while the proportion of on-farm emissions is declining slightly due to better technologies. I want to briefly note that food processing is not bad in and of itself. Food processing has been utilized effectively since the beginning of time. And technology advances allow for nutrient preservation, extended shelf life, and food safety, as in frozen fruits and vegetables that are quickly frozen on the same day they are picked, thus preserving taste and nutrition, or canned vegetables and fruits that retain most nutrients and can be preserved without refrigeration, or dipping fruits in food-safe wax to prevent damage during transport. Food processing is described in different levels from minimal to ultra. Consumption of highly palatable ultra-processed foods that are far removed from their original whole state and have added ingredients and preservatives have been positively associated with overconsumption, obesity, and other chronic diseases. [MUSIC PLAYING]
