What you eat has real consequences for your personal health. But food is also a factor in the broader areas of public health and planetary health. All these levels of human well-being are affected by our diets and by our entire food systems — the human-made network that (if we're fortunate) brings food to our plates. So that includes agriculture, processing, distribution, consumption, management of food waste, and the invisible policies from governments and corporations that are behind what's grown, what's subsidized or not, what's advertised and promoted or not, and ultimately what you eat.
Turns out food plays a role in health from person to planet. So if we take food-related steps to improve one category of health, we can potentially make improvements in all. You can visualize this idea in the Venn diagram above.
Excessive meat & dairy consumption is bad for personal health.
In the realm of personal health, food is now a significant factor in chronic, non-communicable diseases, including cardiovascular, diabetes, and cancers. According to the ongoing scientific Lancet study called the Global Burden of Disease: "Suboptimal diet is responsible for more deaths than any other risks globally, including tobacco smoking … highlighting the urgent need for improving human diet across nations.” And while 'suboptimal diet' occasionally means undernutrition (too few calories, i.e., not enough to eat) these days it usually means too many calories, too little fibre, too few vegetables and whole foods, and far too much in the way of animal-source foods.
These diseases are all multi-factorial, with contributions from genetics and environmental realities, like pollution, that are mostly outside our control. And if you live with diabetes, heart disease, or cancers, it doesn't mean your condition is definitely food-related — or that your condition is your fault — but that certain eating patterns may have played a role. And central to illness-inducing eating patterns is too much meat.
Excessive meat & dairy production is bad for public health.
Similarly, in the realm of public health, food is key. Obesity, now a major public health problem, is multi-factorial but often linked to diet. Pandemics, a growing public-health scourge, are exacerbated by the ways we produce food — including in factory farms of animals like chickens and pigs, where we've seen the rise of H1N1 swine flu and H5N1 avian flus. Antibiotic resistance, another public-health worry, is partly a result of excessive prescription of antibiotics in human medicine. But the main over-use of antimicrobials has been in animal agriculture for the production of meat, dairy, and eggs — though this is usually overlooked in public discourse. Most antibiotics in animal agriculture are given to otherwise healthy animals to help them tolerate the harsh conditions common to industrial farming systems, including crowding and unnatural diets. Yup, that's how most meat is made.
Animal-centred agriculture and diets are terrible for planetary health.
Then there's planetary health, meaning climate stability and ecosystem resilience. Unfortunately, the ways we produce food today are threats to forests and wetlands, to clean water and air, to maintenance of natural habitat for animals and plants, and for climate that is hospitable to humans. Of all food-related emissions of greenhouse gases (GHGs), food waste is responsible for about one-quarter. Even worse, animal agriculture for meat and dairy is responsible for more than half of food-related GHGs — though meat and dairy provide humans with only 20% of average calories.
I said there's heavy overlap among personal, public, and planetary health. And what's the key point of intersection? Too many 'food animals' making too much meat, dairy, and eggs. And when we make progress on that, we make progress on all of planetary, public, and personal health.
Global Burden of Disease (GBD) 2017 Diet Collaborators. Health effects of dietary risks in 195 countries, 1990-2017: a systematic analysis for the GBD Study 2017. The Lancet. May 11, 2019. Vol 393, Issue 10184. p 1958-1972. https://www.thelancet.com/article/S0140-6736(19)30041-8/fulltext
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McCubbin, K.D. et al. "Knowledge Gaps in the Understanding of Antimicrobial Resistance in Canada." Front. Public Health. 20 Oct 2021. Review Article. Sec. Infectious Diseases: Epidemiology and Prevention. https://www.frontiersin.org/articles/10.3389/fpubh.2021.726484/full
Oxford Uehiro Centre for Practical Ethics. "Factory farms are breeding grounds for pandemics." June 8 2021. Aaron S. Gross. https://www.practicalethics.ox.ac.uk/tol/gros
Selvik, H.A. and Fullilove, R.E. From Global Thinking to Local Action: The Planetary Diet as Chronic Disease Prevention. Public Health Rep. 2020. Jul-Aug: 135(4). 424-427. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7383765/