Healthy diets are also more environmentally friendly

You are what you eat, an old aphorism has it. It turns out that this truism is really true in more ways than one. To wit: not only are healthier diets essential for healthier lives. They are also better for the environment.

“Lower-carbon diets aren’t just good for the planet, they’re also healthier,” stress the authors of a new study from Tulane University who examined the carbon footprint of the foods more than 16,000 Americans consume in a day.

The scientists ranked diets based on the amount of greenhouse gas that is emitted per 1,000 calories provided by a food. They also rated the nutritional value of foods consumed in five different diets common in the United States. The diets that had the lowest carbon footprints were those that depended more on greens and less on meats. However, these diets also lacked important nutrients such as iron, calcium, and vitamin D, which they attributed to lower intakes of meat and dairy.

“People whose diets had a lower carbon footprint were eating less red meat and dairy – which contribute to a larger share of greenhouse gas emissions and are high in saturated fat – and consuming more healthful foods like poultry, whole grains and plant-based proteins,” said Diego Rose, a professor of nutrition and food security at Tulane University’s School of Public Health and Tropical Medicine.

Conversely, diets with the largest impact had emissions five times the emissions of diets with the lowest impact; namely, diets heavy in animal protein such as beef, dairy products, game and solid fats.

Then again, this should come as no surprise. Earlier studies showed that red meat requires 28 times more land to produce than pork or chicken and it emits five times more greenhouse gases. Compared to potatoes, wheat, and rice, the impact of beef production per calorie is starker still. It entails 160 times more land and produces 11 times more greenhouse gases.