Small Changes in Your Diet Can Reduce Your Carbon Footprint by 25% and Boost Your Life Expectancy

New studies underscore the health and environmental advantages of swapping animal proteins for plant-based replacements in the diets of Canadians. The study noted marked improvements in life expectancy and decreased carbon emissions, primarily when exchanging red and processed meats. However, these benefits vary depending on the specific animal protein being replaced, and there is a sex difference in health outcomes.

Canada’s latest Food Guide introduces a significant shift in nutritional guidance, moving away from traditional food categories, including meat and dairy. Instead, it emphasizes the importance of plant-based proteins. However, the full ramifications of replacing animal proteins with plant proteins in the diets of Canadians are still uncertain.

New research undertaken at McGill University in partnership with the London School of Hygiene & Tropical Medicine delivers convincing proof that partially replacing animal proteins with plant proteins can enhance life expectancy and decrease greenhouse gas emissions. Crucially, the research indicates that the benefits are dependent on the kind of animal protein being substituted.

The research, appearing in Nature Food, utilised data from a national nutrition survey to examine the dietary practices of Canadians. The investigation modelled partial replacements (25% and 50%) of either red and processed meat or dairy with plant protein sources like nuts, seeds, legumes, tofu, and fortified soy drinks, while analysing a blend of nutrition, health, and climate impacts.

A prior study showed that red and processed meat and dairy are the leading contributors to Canada’s diet-related greenhouse gas emissions. Surprisingly, the current study uncovered a 25% decrease in a person’s diet-related carbon footprint if they substituted half of their red and processed meat consumption with plant protein sources. In contrast, changes due to dairy replacements resulted in smaller reductions of up to 5%.

Olivia Auclair, first author and recent doctoral graduate in McGill’s Department of Animal Science explains, "Our findings illustrate that benefits to human and planetary health don't require drastic alterations to diets, like adopting restrictive eating patterns or completely excluding certain food groups. They can be achieved by simply making partial substitutions, particularly of red and processed meats, with plant protein food."

It is well known that diets high in animal products increase the risk of heart disease, diabetes, and some cancers. The researchers estimated that if half of the red and processed meat in a person's diet was replaced with plant protein food, their life expectancy could increase by almost nine months due to a lower risk of chronic disease.

The study found that men could see more benefits from making the switch, with a life expectancy increase that is twice that for women. In contrast, partially substituting dairy with plant protein foods resulted in smaller life expectancy gains, with a trade-off of increased calcium deficits by up to 14%.

"I hope our results will encourage people to make healthier and more environmentally friendly food choices, and guide the future of food policy in Canada," states senior author Sergio Burgos, Associate Professor in McGill’s Department of Animal Science and a researcher at the Research Institute of McGill University Health Centre.

As an increasing number of people are seeking health-conscious and sustainable diets, the findings of this study present a valuable guide, equipping individuals to make more conscious choices that benefit both their personal well-being and the environment.

Patricia Eustachio Colombo, co-author and Honorary Research Fellow at the London School of Hygiene & Tropical Medicine’s Centre on Climate Change & Planetary Health, explains, "Raising the consumption of plant-based foods while reducing red and processed meat can have significant benefits for health and the environment. These adjustments involve relatively small changes in the diets of most Canadians."

Reference: "Partial substitutions of animal with plant protein foods in Canadian diets have synergies and trade-offs among nutrition, health and climate outcomes" by Olivia Auclair, Patricia Eustachio Colombo, James Milner and Sergio A. Burgos was published on the 16th of February 2024 in Nature Food.