Is ‘Environmentally-Friendly’ Animal Agriculture Possible?
When confronted with the widely accepted environmental benefits of a plant-based diet, many people argue that omnivorous diets can be just as sustainable, depending on the production methods used. Supporters of environmentally friendly omnivorous diets cite organic animal products and cage-free and grass-fed animals as sustainable options. Surely there has to be a way to enjoy meat, eggs, and dairy without contributing to the environmental damage those industries cause, right? The answer seems to be: Probably not.
In this study, several European researchers investigated the environmental sustainability of omnivorous diets with regard to both animal product consumption and production method. Data was collected from roughly 35,000 French adults in the form of self-reported answers to a food frequency questionnaire.
Diets were scored based on preference for plant foods over animal products, as well as preference for organic versus conventional foods. Several environmental impacts were also calculated, including greenhouse gas emissions, land use, and cumulative energy demand. Participants were placed into five groups, designated Q1 through Q5, with Q1 having the lowest preference for plant foods and Q5 having the highest.
Nutritionally, a higher preference for plant foods correlated with a lower protein intake overall, but a higher intake of plant protein. It also was associated with a higher intake of unsaturated fatty acids and a lower intake of saturated fats. Those with the highest preference for plant foods also generally consumed more vitamins and minerals, excluding vitamin B12.
After adjusting for age, energy intake, and sex, the researchers found that diets rich in plant foods correlated with lower greenhouse gas emissions, less land use, and lower total energy requirements. Animal products were responsible for 80% of the greenhouse gas emissions among participants in Q1, and 60% among those in Q5. This means that even small amounts of animal products contribute enormously to environmental impact. Switching to organic food production methods only reduced environmental impact for those in Q4 and Q5, meaning that diets rich in animal products were not more environmentally friendly.
Regardless of dietary preferences, products obtained from ruminant animals like cows and sheep were responsible for about half of total greenhouse gas emissions. No significant environmental benefits were found when comparing organic beef and milk production to conventional methods.
Switching to consuming non-ruminant animals like pigs and chickens did reduce environmental impact, but organic methods were found to be potentially more environmentally harmful than conventional ones. Diets rich in plant products caused the least environmental damage overall, and organic plant-based diets were the only ones that significantly outperformed their conventional counterparts.
The researchers qualified their study by reminding us that a single study based on self-reported data is not easily generalized to the entire population. Respondents may have overestimated or underestimated their consumption of plant foods and organic foods, and those who responded are possibly more concerned with health and nutrition than the general population.
Furthermore, the environmental impact of similar diets may vary considerably across different regions, owing to different soil types, rain levels, and farm management styles. In addition, the researchers did not measure pesticide use, fertilizer use, or soil sustainability, nor did they take into account the origin or seasonality of foods. Also, the environmental impacts were calculated with respect to the farming stage, but transportation, processing, or transformation stages were not considered.
However, the researchers noted that their findings solidly support the general inferences of their study: that plant-based diets are better for the environment and that organic production only marginally improves the sustainability of animal agriculture. If further studies support these results, the collective data could strengthen the environmental argument for a plant-based diet and undermine the notion of “environmentally friendly” animal agriculture.