Can sustainable diets help reduce carbon emissions?

Opinion: A truly sustainable diet needs to adapt not only to each individual, but also change throughout their lives

By Katie Davis, UCD

The way we produce and eat food is unsustainable from a health and environmental point of view. We have to have food, but the scale and method of food production is widely recognized as unsustainable. Land use, water use, and greenhouse gas emissions are just a few of the metrics that describe the environmental impact of food production.

Food production requires approx. 40% of the available land on earth. is responsible for 70% of total freshwater use and emits at least 30% of global greenhouse gas emissions annually. This means that agriculture and food production must play a critical role in meeting climate commitments, as Ireland’s legally binding commitment to achieve net zero carbon emissions by 2050.

Agriculture is the largest emitter of greenhouse gases in Ireland, generating more than 37% of the country’s total emissions. High greenhouse gas emissions are the result of both large-scale food production and what we choose to produce. A report of the Eat-Lancet Commission suggests that we will cause irreversible environmental damage in less than 30 years without large-scale changes in food production and emissions. Food production inevitably produces some greenhouse gas emissions, but there is room for reduction.

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From Today With Claire Byrne of RTÉ Radio 1, discussion of Irish agriculture and emissions targets with Oisin Coughlan of Friends of the Earth Ireland and Justin McCarthy of Framers Journal

Recommendations for sustainable diets are often driven by a food’s “carbon footprint” or the amount of greenhouse gases associated with the production and transportation of that food. Animal products, such as meat and dairy, produce more emissions on average compared to plant-based foods. Therefore, the proposed sustainable diets are rich in plant-based foods such as whole grains, fruits, vegetables, nuts, and legumes and less in animal-based foods, particularly red and processed meats. Research suggests that greenhouse gas emissions can be reduced simply by choosing foods with a lower carbon footprint.

Encouraging plant-based food intake is nothing new. Food-based dietary guidelines, such as HSE Healthy Eating Guidelines recommend a high intake of whole grains, fruits, vegetables, and other plant-based foods as part of a healthier diet. The way we produce food puts both the health of the planet and our own health at risk. Unhealthy diets now lead to more poor health than drug, tobacco, and alcohol use combined. Diets with a high intake of vegetables, whole grains, and other plant-based foods are associated with lower risk of disease and better health. Therefore, a shift to a more sustainable diet may be more beneficial to human and planetary health.

However, meat and dairy products provide vital micronutrients such as vitamin B12, iodine, zinc and calcium. Current evidence suggests that diets that emit fewer greenhouse gases have lower nutritional adequacy, meaning they may not provide healthy amounts of all essential nutrients. Plant-only Diets, such as a strictly vegan diet, have inadequate levels of essential nutrients, meaning they are not nutritionally complete without supplementation. Therefore, receive all essential nutrients through dietIt is important to eat a variety of foods from both animal and plant sources.

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From RTÉ 2fm’s Jennifer Zamparelli show in 2019, dietitian Orla Walsh on the vegan diet

There is no clear guide on how to make a person’s diet sustainable. sustainable diets are definite for him Food and Agriculture Organization of the UN (FAO) as one that “promotes all dimensions of people’s health and well-being; has low pressure and environmental impact; is accessible, affordable, safe and equitable; and is culturally acceptable”. By this definition, healthy and sustainable diets would differ by country, as well as between different populations.

Recent Nutrition Research shows that people respond differently to diets due to a variety of factors including personal lifestyle choices and demographics. Our nutritional needs change throughout our lives with factors such as age, body size, and physical activity levels influencing what our bodies need.

For example, children or older adults. require higher intakes of some critical micronutrients like calcium to support healthy growth or bone health. Alternatively, someone who is very physically active may need a higher proportion of carbohydrates in their diet compared to someone who is less active. For a diet to be truly sustainable, it must be tailored not only to each individual, but it must also change throughout an individual’s lifetime.

There is no clear guide on how to make a person’s diet sustainable.

The evidence to date on sustainable diets is limited and theoretical. No clinical trials have tested the efficacy, safety, and acceptability of a more sustainable diet. Although some recommended diets have been published, there is evidence that some recommendations would not meet the nutrient requirements for all adults. While nutrition research can model a better diet and predict what will happen, there is no way to know until it is actually tested.

the MyPlanetDiet The study aims to critically examine what a sustainable diet is and whether diet-related greenhouse gas emissions can be reduced in a safe and acceptable way. The study is the world’s first human trial testing the effects of a more sustainable diet and we are currently recruiting volunteers.

Katie Davis is a doctoral candidate at the Institute of Food and Health a UCD. His research aims to test the effects of more sustainable diets under the SuHeGuide Project which is a collaboration between Teagasc, UCD Institute of Food and Health, Center for Public Health at Queen’s University Belfast Y School of Food and Nutrition of the UCC.

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The views expressed herein are those of the author and do not represent or reflect the views of RTÉ

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