Re: Call for emergency action to limit global temperature increases, restore biodiversity, and protect health
We congratulate your collective initiative demanding urgent action against climate change. However, despite citing many useful strategies, you only made a passing mention about production and distribution of food1 without touching in any depth on the paramount importance of our eating habits to human and planetary health. For instance:
• We agree with you that the destruction of nature must be stopped for the sake of all the living creatures in this Planet. But let’s clarify that one of the greatest drivers of habitat destruction is our meat consumption: cattle production alone causes 40% of deforestation globally. Our food system constantly converts natural habitats into farmland and reduces biodiversity. Consequently, the biomass of humans and of livestock far surpass that of wild mammals. The same applies to birds where the biomass of domesticated poultry is about three times higher than that of wild birds.
• We agree with you that heating is contributing to declines in the yields of major crops. But according to the Food and Agriculture Organisation of the United Nations (FAO), 33% of croplands are used for livestock feed production. If we add that animals take large amounts of feed to produce 1 kg of meat (cattle take 25 kg, mutton 15Kg, pork 6.4Kg, and poultry 3.3Kg of feed to produce 1 kg of meat), it does not make much sense to use our limited resources in this manner.
• We agree with you that our health is affected by the rapid changes in climate we are experiencing. However, while 9.43% of all deaths have been associated with non-optimal temperatures, dietary risk factors caused 22% of all deaths in 2017. These deaths were mostly due to noncommunicable diseases[8,9] which in turn cause 71% of all deaths and can be prevented by tackling the root of the problem, our diet.
• We agree with you that the greatest threat to public health is the failure of world leaders to keep the average temperature rise below 1.5°C and to restore nature. But clinicians have also failed at helping patients change the unhealthy diets that drive the destruction of nature and are a major source of greenhouse gas (GHG) emissions (animal-based foods corresponds to 57% of the global GHG emissions from food production compared to 29% from plant-based foods).
If you truly recognise that more can and must be done and that only fundamental changes will reverse our situation, then let’s talk about our eating habits: the fundamental actions everyone can take to do what’s vital for the planet while enhancing their own vitality. In fact, individuals have been changing their diets already due to health and environmental concerns[11,12] However, to fight climate change, sustainable diets must become generalised and clinicians are uniquely placed to encourage patients to make this transition.
As you say, clinicians must do all they can, and they should proactively contribute to prevention of further damage and act on the root causes of the crisis. Since human nutrition is at the crux of the problem, they should educate and empower their patients to change their diets towards less processed and more plant-based foods.
Some clinicians may argue they lack training to provide dietary advice, but if they often recommend their patients to stop smoking without being specialised in pneumonology, why can’t they recommend dietary changes that are known to improve healthcare outcomes and help fight climate change as the EAT-Lancet Commission explained so well? At this point, it comes down to honouring the Hippocratic oath and its “First do no harm” concept by stopping to neglect the power nutrition has over health and sustainability. And if they consider they lack training, they can resort to the many resources available to clinicians, such as:
• The American College of Lifestyle Medicine provides extensive online and in-person resources for different types of clinicians up to Board certification in Lifestyle Medicine:
o https://www.lifestylemedicine.org/ACLM/Education/ACLM/Education/Overview... 
o https://www.lifestylemedicine.org/ACLM/Certification/Approved_CME 
• Plant-based Health Professionals UK in association with the University of Winchester offer the first University-based course on plant-based nutrition in the UK along with a many other resources throughout their website:
o https://plantbasedhealthprofessionals.com/pbn-course 
• The Physicians Committee for Responsible Medicine offers many resources for clinicians including CMEs:
• Harvard University provides several online nutrition courses for clinicians:
o https://online-learning.harvard.edu/subject/nutrition 
• A new white paper by Food+Planet that “provides a road map of how we might meaningfully close the gap so that we can create a movement among nutrition professionals to catalyse change within the food system”, downloadable here:
o https://foodandplanet.ck.page/ 
As we all know, climate change is already disturbing societies worldwide and drastic changes should be implemented at all levels to protect our children’s legacy. The large-scale dietary changes towards predominantly plant-based patterns that clinicians should lead can make a great impact to stabilise Earth’s climate, protect nature, and improve human health and productivity.[13,19] So, instead of hoping we develop technologies to remove GHG from the atmosphere, let’s reduce the methane and all the other GHG produced by animal farming by switching from animal to plant protein sources now.
COVID-19 demonstrated that global action and unprecedented funding can be implemented very quickly. It also showed that after eons of evolution we still follow a fight versus flight behaviour. But if we are the most intelligent beings in this planet, let’s behave as such instead of as the worst invasive species in history. After all the amazing progress we have achieved, now we face the ultimate challenge to evolve beyond our primal inclinations by learning to eat to live and thereby reach the best version of ourselves, physically, mentally, and ethically.
To summarise, in a situation where we need to do everything possible, we should invest our limited time on the exponential effect of drastically changing the actions every human does many times daily: eating and drinking. We can be sure we’ll all die someday, but what if we can give our children healthier lives and fight climate change at the same time? It sounds like the right thing to do.
1. Atwoli L, Baqui AH, Benfield T, et al. Call for emergency action to limit global temperature increases, restore biodiversity, and protect health. The Lancet. 2021;398(10304):939-941.
2. Pendrill F, Persson M, Godar J, Kastner T. Deforestation displaced: Trade in forest-risk commodities and the prospects for a global forest transition. Environmental Research Letters. 2019;14.
3. Benton T. G. BC, Harwatt H., Pudasaini R., Wellesley L. Food system impacts on biodiversity loss. 2021.
4. Yinon M. Bar-On RP, Ron Milo,. The biomass distribution on earth. PNAS. https://www.pnas.org/content/115/25/6506#sec-6. Accessed 23/09/2021.
5. Food and Agriculture Organization of the United Nations. Livestock and Landscapes. http://www.fao.org/3/ar591e/ar591e.pdf. Published 2012. Accessed 18/09/2021.
6. Alexander P, Brown C, Arneth A, Finnigan J, Rounsevell MDA. Human appropriation of land for food: The role of diet. Global Environmental Change. 2016;41:88-98.
7. Zhao Q, Guo Y, Ye T, et al. Global, regional, and national burden of mortality associated with non-optimal ambient temperatures from 2000 to 2019: a three-stage modelling study. The Lancet Planetary Health. 2021;5(7):e415-e425.
8. GBD 2017 Diet Collaborators. Health effects of dietary risks in 195 countries, 1990-2017: a systematic analysis for the Global Burden of Disease Study 2017. Lancet (London, England). 2019;393(10184):1958-1972.
9. World Health Organization. Noncommunicable diseases. https://www.who.int/news-room/fact-sheets/detail/noncommunicable-diseases. Published 2021. Accessed 18/09/2021.
10. Xu X, Sharma P, Shu S, et al. Global greenhouse gas emissions from animal-based foods are twice those of plant-based foods. Nature Food. 2021;2(9):724-732.
11. McCarthy J. DS. Nearly One in Four in U.S. Have Cut Back on Eating Meat. https://news.gallup.com/poll/282779/nearly-one-four-cut-back-eating-meat.... Published 2020. Accessed 18/09/2021.
12. European Consumer Organisation (BEUC). One bite at a time: consumers and the transition to sustainable food. https://www.beuc.eu/publications/one-bite-time-consumers-and-transition-.... Published 2020. Accessed 18/09/2021.
13. Willett W, Rockstrom J, Loken B, et al. Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet (London, England). 2019;393(10170):447-492.
14. ACLM. Lifestyle Medicine Education. https://www.lifestylemedicine.org/ACLM/Education/ACLM/Education/Overview.... Published 2021. Accessed 24/09/2021.
15. ACLM. American College of Lifestyle Medicine Resources for Certification. https://www.lifestylemedicine.org/ACLM/Certification/Approved_CME. Published 2021. Accessed 24/09/2021.
16. Plant-based Health Professionals UK. Plant-based Nutrition Course. https://plantbasedhealthprofessionals.com/pbn-course. Published 2021. Accessed 24/09/2021.
17. Harvard University. Online Nutrition Courses. https://online-learning.harvard.edu/subject/nutrition. Published 2021. Accessed 24/09/2021.
18. Vogliano C. G, K., Chou, S., Palmer, S. . Empowering Nutrition Professionals to Advance Sustainable Food Systems [White Paper]. 2021.
19. Harwatt H. Including animal to plant protein shifts in climate change mitigation policy: a proposed three-step strategy. Climate Policy. 2019;19(5):533-541.
Competing interests: Dr. Rojido declares no conflicts of interest Dr. Kassam is the founder of Plant-Based Health Professionals UK and co-founder of Plant-Based Health Online Dr. Katz is the founder and CEO of Diet ID, Inc, a company working to include objectively measured diet quality among vital signs