This article discusses what is an ecological diet, why sustainable food sources matter, and the evidence behind claims it could improve your health. The Lancet is one of the leading medical journals worldwide, and recently published an article called Food Planet Health that summarised the findings of the EAT-Lancet commission. The Commission brought together 19 independent Commissioners from 16 countries to develop global scientific targets based on the best evidence for a healthy diet and sustainable food production for the planet. This is the basis of an ecological diet.
It is widely recognised and reported by the World Health Organisation (WHO), that an unhealthy diet is one of the largest modifiable risk factors for disease and death. More recently it has been shown that an unhealthy diet now poses a greater risk to ill health and death than unsafe sex, alcohol, drug and tobacco use combined1. The authors investigated if an ecological diet that benefits health could also benefit the planet.
“dietary changes from current diets towards healthy diets are likely to result in major health benefits” and would “prevent approximately 11 million deaths per year, which represents between 19-24% of total deaths among adults”
Today, globally more than 820 million people are undernourished, while 2.1 billion adults are overweight or obese2. The authors define a healthy diet as one that optimizes health, defined broadly by the WHO as being a state of complete physical and social wellbeing, not just an absence of disease2.
What is the evidence?
Primarily plant-based diets, such as vegan, vegetarian, pescatarian and semi-vegetarian diets have repeatedly been shown to lower the overall risk of death by 10-20% compared with omnivores3-5. More specifically, consumption of plant-based foods has been linked with decreased risk of type 2 diabetes and coronary heart disease suggesting that just a shift towards plant based, without adopting a vegan diet would be beneficial2.
Eating processed red meat (beef, pork or lamb) has been associated with an increased risk of death from any cause and cardiovascular disease2. There is also limited evidence that diets that are naturally low in red meat such as the Mediterranean diet are associated with increased longevity. Additionally, processed red meat has now been determined by the International Agency for Research on Cancer review to be a group 1 carcinogen, meaning there is sufficient evidence to demonstrate it causes colorectal cancer formation in humans. In contrast, no association with increased risk of death has been convincingly shown with poultry or fish2.
Instead, eating one to two servings of oily fish a week, might reduce the risk of dying from heart disease by more than one third6. Legumes have been shown to reduce cholesterol and been associated with reducing the risk of heart disease2. Soya consumption during childhood has also been associated with a decreased risk of breast cancer7.
Nuts which contain primarily unsaturated fats, fibre, vitamins, minerals, antioxidants and phytosterols, have repeatedly been shown to reduce cholesterol, abdominal girth, blood sugar, inflammation, risk of cardiovascular disease, obesity, type 2 diabetes and overall mortality2.
So what does a sustainable healthy diet look like?
The proposed diet largely consists of vegetables, fruits, whole grains, legumes, nuts, and unsaturated oils, includes a low to moderate amount of seafood and poultry2. The diet does not include sugar, refined grains and starchy vegetables, with no or a low quantity of red meat.
What we eat also has a huge impact on climate stability and ecosystem resilience. At present the world is failing to meet the United Nations Sustainable Development Goals (SDGs) and the Paris Agreement on climate change. The proposed move by these authors to a mainly plant based diet, would not only improve our health, but also that of the planet.
Preventing chronic disease, decreasing mortality and improving climate stability are surely important goals we call all get behind? This could be the start of the ‘Great Food Transformation’2.
1. Haddad, L. et al. Food systems and diets: Facing the challenges of the 21st century. (2016).
2. Willett, W. et al. Food in the Anthropocene: the EAT-Lancet Commission on healthy diets from sustainable food systems. Lancet (2019).
3. Orlich, M. J. et al.Vegetarian dietary patterns and mortality in Adventist Health Study 2. JAMA Intern Med173, 1230–1238 (2013).
4. Segovia-Siapco, G. & Sabaté, J. Health and sustainability outcomes of vegetarian dietary patterns: a revisit of the EPIC-Oxford and the Adventist Health Study-2 cohorts. Eur J Clin Nutr1 (2018).
5. Aune, D. et al.Fruit and vegetable intake and the risk of cardiovascular disease, total cancer and all-cause mortality-a systematic review and dose-response meta-analysis of prospective studies. Int J Epidemiol46, 1029–1056 (2017).
6. Mozaffarian, D. & Rimm, E. B. Fish intake, contaminants, and human health: evaluating the risks and the benefits. JAMA296, 1885–1899 (2006).
7. Lee, S.-A.et al.Adolescent and adult soy food intake and breast cancer risk: results from the Shanghai Women’s Health Study. Am. J. Clin. Nutr.89, 1920–1926 (2009).