The Study

A new commission report in The Lancet, which was written by nearly 40 scientists from 16 countries, gives recommendations for how to eat for better health — both human health, and the health of the planet. It also takes into account the dietary needs of different populations around the world. “The goal of this Commission was to identify a pathway to feeding the anticipated global population of 10 billion people in 2050 a diet that is healthy and sustainable,” explains commission report lead author and THI council member Walter Willett, MD, DrPH,a physician, nutrition researcher, and the Chair of the Department of Nutrition at the Harvard School of Public Health. “This is a huge challenge because at present we are not feeding today’s 7.2 billion inhabitants diets that are healthy; nearly a billion are still under nourished, about 2 billion are overweight or obese, and most of the rest consume poor-quality diets that result in suffering and premature mortality. At the same time, the way we produce our food is fueling climate change and degrading the very resources that are needed for food production.”

So, “the commission reviewed the best available evidence on diet and health, including all types of studies in humans, and concluded that diets consisting largely of whole plant foods, but that also could include modest amounts of fish, poultry, red meat, and dairy foods, will provide optimal health and could prevent 20 to 25 percent of premature deaths,” Willett says. “Combining this with data on the environmental footprints of major food groups, we examined whether such diets can keep the world within sustainable environmental boundaries. We found that globally adopting a healthy plant-based diet, sometime called a flexitarian diet, would keep us within limits for greenhouse gas production, but not for other environmental boundaries. However, by also adopting better agricultural practices and greatly reducing food loss and waste, we have the potential to feed the world a healthy diet and pass on to our children a healthy planet as well.”

“The study concludes that our current food system (production, distribution, and consumption) poses a significant global threat in terms of both health and environmental sustainability,” notes THI council member Alice Ammerman, DrPH, Professor in the Department of Nutrition at the Gillings School of Global Public Health and UNC-Chapel Hill, and Director of the Center for Health Promotion and Disease Prevention, who was not involved in the report. “Substantial shifts in all these areas will be required to reduce this risk, but the good news is that many of the same approaches will result in improvement in both individual health and stability of the global ecosystem.”

“While there is near universal support for improved health and protection of the environment, there will likely be many who disagree with some of the required changes if they involve either personal or corporate sacrifice,” Ammerman adds.

The report concludes “that a Great Food Transformation is needed to switch to a healthier, more environmentally friendly diet that avoids the environmental and social catastrophe awaiting us if we continue with business as usual, or make only minor changes,” says THI council member David Cleveland, PhD, Professor of Environmental Studies at the University of California, Santa Barbara. “This flexible diet consists of mostly plant foods, with little or no red and processed meat, added sugar, or refined grains. Though changing to this diet makes the largest contribution to moving to and staying within sustainable planetary boundaries, more efficient farming and large reductions in food waste will also be needed.”

“The technophiles who don’t understand or accept the science will say that the way to avoid planetary collapse is more technology to keep eating the way we are, ignoring the evidence for the need to reduce our demand to stay within biophysical and sociocultural limits,” Cleveland adds. “The dominant food industry, that values profit with no concern for public health or the pending climate and environmental catastrophe, will employ their play book, manufacturing doubt about the scientific results in order to keep up profits. And finally, and most irritatingly, are the pessimists who will accept the conclusions about the need to change, but will say a Great Food Transformation could never happen.”

A Look at the Media Coverage

Media coverage of the study included headlines such as “The way we eat could doom us as a species. Here’s a new diet designed to save us.” (Vox), “A bit of meat, a lot of veg – the flexitarian diet to feed 10bn” (BBC), “Seeds, kale and red meat once a month – how to eat the diet that will save the world” (The Guardian), “This Diet Is Better For the Planet. But Is It Better For You, Too?” (NPR), “New Diet Guidelines to Benefit People and the Planet: More Greens for All, Less Meat for Some” (NYTimes), and “New ‘planetary health diet’ can save lives and the planet, major review suggests” (CNN).

Overall, Willett found the big picture takeaways presented by the media in general “quite accurate,” and he said they “seemed to have been communicated quite well.”

Ammerman notes that “while some media coverage has predicted gloom and doom, most recognize both the significant potential benefits, as well as the challenges required, to avoid global disaster. The urgency of the problem has been accurately highlighted, and most reporting has included a ‘call to action’ with specifics about what individuals and governments can do to change the current course.”

Cleveland says the media coverage he’s seen was “good, pretty accurately reflecting the content of the report. Also, it has importantly raised some questions about the report, including interviewing critical scientists, because it’s important to be reminded of the uncertainty in all science. Several stories discussed some controversies about the health effects of the recommended diet, but most agreed with the report that diets very similar to the one advocated by the report will be needed to avoid environmental catastrophe if we are to feed 10 billion people by 2050.”

How YOU Should Apply the Findings to Your Life

“We do hope that people will shift their diets in ways that will promote their own well-being and at the same time allow us to pass on to our children and grandchildren a healthy planet,” Willett says. “For many Americans, this will mean substantially reducing consumption of red meat and replacing it with health plant sources such as nuts, soy, and beans. This would mean about one serving of red meat per week, or a large steak once a month. Poultry and dairy foods could be included in modest amounts. This way of eating is consistent with the traditional Mediterranean diet, which has well documented health benefits as well as enjoyable eating, but can also be assembled with foods and culinary traditions of all parts of the world.”

As for Ammerman, “the most important takeaway is that we are truly facing a global crises, but unlike many International problems, this one can be addressed by immediate individual level changes in addition to calling for corporate and governmental commitment to action.”

Cleveland says that the “message people should get from this report is one of hope — hope that that there is still time to haul back from the precipice — and determination — to commit to the huge, concerted effort it will require.” A section of the report lays out “some steps toward a healthy sustainable diet that governments (restrict advertising and marketing of unhealthy, unsustainable foods), food industry (reduce portion size), health care workers (promote breast feeding), and farmers (increase water use efficiency) can take,” he adds. “For these to have a large enough impact, they will have to be mandated and/or supported by changes in knowledge, attitudes and policies at the highest levels, which means we all need to be advocating for the needed policy changes — but we can all start moving to more sustainable, whole food, plant based diets now, the next time we eat!”

Read THI Founder David Katz’s take here.