Is what's good for the planet also good for your health?

Moving from a high to a low emitting diet could save 24,000 lives a year, according to a new study

Climate change is a pressing issue, and mitigating it may demand some personal sacrifices. Our food system and dietary choices are linked to climate change because food production contributes about one third of greenhouse gasses worldwide. 

Some diets contribute more greenhouse gasses than others.

Some food patterns pose more chronic disease risk than others.

Are carbon footprint and disease risk aligned?

Production of animal foods emits more greenhouse gasses. Beef production emits 10 times more than chicken, and 20 times as much as growing legumes, nuts and seeds. We also know that diets high in red and processed meat are linked with higher risk of heart disease, cancer and overall earlier death.

There are very few studies about the relationship between diet, environment and health, according to researchers from Tulane University, led by Donald Rose, and some of the data relies on specific populations, such as Seventh-Day Adventists, who are not representative of the general population, as their lifestyle and demographics aren’t just a choice of plant-based diets. The researchers set out to check personal health/planet health relationships in a representative population. The study appears in the journal Public Health Nutrition.

The researchers looked at the diet of almost 13,000 nationally representative Americans aged 18-64 years. Each diet’s greenhouse gas was calculated. The researchers used a well established diet mortality tool called PRIME (the Preventable Risk Integrated ModEl), which estimates the number of lives that can potentially be saved by behavior changes – such as diet, exercise, smoking and alcohol – in a population. They then simulated what would happen if they moved the population from the highest carbon emitting diet to the lowest.

And the results:

Moving from a high to a low emitting diet would result in 24,000 lives saved a year, which is 2 percent less deaths in the US. Most of the lives saved in this simulation would be thanks to a reduction in heart disease deaths.

What would be causing the reduced risk of death on the low carbon diet? The low carbon diet has more plant foods and less beef.

The results of this study concur with another study from the United Kingdom, which simulated a transition to a less-meat diet, and found a reduction in deaths lined up with the reduction in emissions – the more meat is substituted with plants the more lives saved.

The authors conclude: “This provides additional evidence that diets which are environmentally less impactful are also more healthful and suggests that efforts to implement more environmentally sustainable dietary patterns in the USA could also reduce mortality from CVD (cardiovascular disease).”

Another study in the journal Climatic Change estimated how even small changes to the diet affect both greenhouse emissions and health. The researchers looked at the risk of diabetes, colon cancer and heart disease, and in the simulation model, a diet’s red and processed meat content was progressively swapped with legumes, grains, fruits and vegetables. The model did not alter added sugar, dairy, eggs or fish. The healthier diet models reduced the risk of heart disease, colon cancer and type 2 diabetes by 20-45 percent while dropping  greenhouse gas emissions 200-800 kg per person a year – depending on the relative shift to plant-based proteins.

No sacrifice at all?

While the percentage of vegetarians in the American population is in the small single digits, and that's unlikely to change, moving from a high meat diet to a lower meat diet can save many lives and improve personal wellness, while also improving our atmosphere.

Lowering the thermostat in summer, increasing it in winter, and cutting on driving may be a price we will each decide to pay in order to cut greenhouse gasses, but when it comes to food, what’s good for the planet will also do you some good personally. 

And eating more plants can be pleasurable – a plant-centric diet can be absolutely delicious, so culinary considerations need not suffer.

Dr. Ayala