Healthier plant-based foods appear to have a lower environmental impact than vegan “junk food,” a new study has found.
The findings come from researchers at Harvard T.H. Chan School of Public Health, along with Brigham and Women’s Hospital (a teaching hospital of Harvard Medical School). They were published in The Lancet Planetary Health journal.
Central to the claim is that healthy plant-based foods require less water, cropland, and fertilizer than animal products.
Healthy “plant-rich” diets were deemed to be those including ample vegetables, fruit, legumes, nuts, and whole grains. Less healthy plant-based foods included refined grains (such as white rice and bread), sugary drinks, sweets, potatoes, and fruit juice.
“The differences between plant-based diets was surprising because they’re often portrayed as universally healthy and good for the environment, but it’s more nuanced than that,” Aviva Musicus, co-author of the study, said in a statement.
They emphasized, however, that despite being less environmentally friendly than whole grain and vegetable-heavy diets, a more junk food-based vegan diet is still superior to those featuring animal products in terms of impact on the planet.
As well as using the most cropland, irrigation water, and fertilizer, animal-based foods also made up the most greenhouse gas emissions. Red and processed meat contributed to 31 percent of all participants’ dietary greenhouse gas emissions. Meanwhile, dairy and poultry made up 13.2 percent and 9.3 percent respectively.
“To be clear, we’re not asserting that less healthy plant-based diets are worse for the environment than animal-based diets. However, our findings show that plant-based diets can have different health and environmental impacts,” Musicus explained.
‘Human health ultimately depends on planetary health’
For the study, researchers assessed the food diaries of more than 65,000 US participants. They looked at the health outcomes and climate impact of their eating habits.
Analysis of the collected data found that those following a healthy animal-free diet were less likely to develop cardiovascular disease. In addition, they were impacting the environment less than those who consumed plant-based foods deemed less healthy.
Daniel Wang, a co-author of the study, says that the findings should influence the development of national dietary guidelines.
“Because human health ultimately depends upon planetary health, future US dietary guidelines should include nuanced consideration of environmental sustainability and recognize that not all plant-based diets confer the same health and environmental benefits,” he said.
The impact of meat and dairy
The team’s findings support previous studies’ claims that diets featuring animal products have a larger environmental footprint than their plant-based counterparts.
Further, a recent report revealed that 15 meat and dairy companies are producing almost as much methane as the entire EU. This is critical due to the ultra-efficiency of methane in increasing global warming. Climate experts have been explicit that, to slow the climate crisis, a drastic reduction in methane emissions is essential.