Want to make the world a healthier place? A pair of ecologists from the University of Minnesota say hold the bacon, burgers and brisket, and opt for Mediterranean, pescatarian or vegetarian diets. The scientists examined these three diets with an eye toward human health, as well as the planet's well-being, and argue that improved culinary habits is a path to a more robust constitution.
"We showed that the same dietary changes that can add about a decade to our lives can also prevent massive environmental damage," said lead study author and global ecosystems expert David Tilman, in a statement.
That eating more greens and less meat is good for both you and your planet is not exactly a new conceit, but the researchers took an explicit look at the potential for 22 types of foodstuffs to impact climate change. Per gram of protein, the greenhouse gas emissions of ruminant animals - cattle, sheep, goats, elk and their ilk - far outstripped that of any other type of food. Emissions per gram protein from growing legumes, on the other hand, was 250 times less than that of ruminants, the scientists reported in the journal Nature on Wednesday.
The researchers' forecast for the global diet of 2050 (the average menu of what everyone's eating everywhere), however, indicates an upswing in pork, dairy and meat consumption by about 25 to 50 percent. A growing middle class in countries like China and India will be the force behind the shift, according to Tilman and his colleague, University of Minnesota graduate student Michael Clark. And that, they say, comes with an associated increase in illnesses like diabetes and heart disease.
There are a few studies that indicate vegetarians live longer than their gristle-and-fat-chewing neighbors. However - and this is an important caveat - the average vegetarian may also be less likely to smoke, less likely to drink, more likely to be hitched and more likely to exercise (all things that are linked to more time on this green earth). It's tough to say if vegetarians are healthier than non-vegetarians specifically as a result of their dietary choices. A review of the medical literature wasn't able to determine if vegetarians with arthritis have improved symptoms, for example, though another meta-analysis found non-meat-eaters have lower blood pressure. The American Cancer Society highlights a handful of reports that found lower rates of prostate and colon cancer among vegetarians, but cautions that "exercise and other healthy habits" could also be the reason for lower rates.
Although cutting back on meat may or may not cure what ails you, from an environmental standpoint it certainly eases the pain. A worldwide shift to a diet with less meat would curb the conversion of forest into farmland, stopping the "destruction of an area of tropical forests and savannas as large as half of the United States," Tilman said. Moreover, he pointed out, such a shift would cut out roughly the same amount of greenhouse gas that cars, planes, train and boats currently emit.