Thread: let's talk a bit more about the recent study that estimated the environmental impacts of U.S. food waste--and also included the finding that healthier diets actually result in higher amounts of food waste. 1/
wapo.st/2qHrTRN?tid=ss…
wapo.st/2qHrTRN?tid=ss…
First, the wasted resources are huge: an area of cropland the size of Pennsylvania (and that doesn't even count grazing land!), 4.2 trillion gallons of irrigation water, and 6 billion pounds of fertilizer each year. 1/4 of food (by weight) and 30% (by calories) wasted. Yikes! 2/
And the tradeoff expressed most simply: wasted food, by weight, grows from ~300g to >500g per capita per day as diet quality improves, because fruits and vegetables (of which more are present in a high quality diet) are also wasted more often than other foods. 3/ 
And here's where it gets tricky: when looking at the *embedded resource use* associated w/ the *wasted food*, as diet quality improves, "wasted cropland" goes down, but "wasted irrigation water" goes up. Why? Because fruits/veg use a lot of irrigation water, but not much land. 4/
So I've seen a lot of the interpretations end at: "It's complicated...healthier diets actually can lead to more food waste and sometimes even more wasted resources...meaning that we need to improve diet quality and reduce food waste at the same time." Which is true. BUT! 5/
This study *only* assessed embedded resource use in the wasted food (as diet quality improves)...*not* the resource use of the *entire diet* (food consumed plus food wasted). I suspect if you look across the entire diet, the tradeoffs between diet quality & waste would lessen. 6/
Our "Shifting Diets" paper (wri.org/shiftingdiets) shows resource use (land, water, GHG) per calorie or gram of protein of different foods. And, since the denominator is "per unit of food consumed," the differing food loss/waste rates across foods are factored in. 7/
Meaning that in general, a shift from animal-based toward plant-based foods - even if shifting to fruits/veg and without reducing food waste - will cause the overall diet's land use and GHG emissions to go down. See also Heller and Keoleian (2014)'s study of the U.S. diet. 8/
Heller/Keoleian link here: onlinelibrary.wiley.com/doi/abs/10.111…
One place where it's a little less clear is what happens to total irrigation water use. Here are global numbers from @WaterFootprintN (not quite sure what the U.S. numbers look like). Compare the blue parts across foods. 9/
One place where it's a little less clear is what happens to total irrigation water use. Here are global numbers from @WaterFootprintN (not quite sure what the U.S. numbers look like). Compare the blue parts across foods. 9/
So to me, this paper just adds more evidence that there are many possible win-wins between health and sustainability in diets. And it makes the important point that fruits/veg use a lot of water and are often wasted - therefore, we should eat healthier *and* waste less food. 10/
But "healthy diets produce more food waste by weight" obscures the fact that if the healthy diet has less meat (esp. beef) in it, then the *overall* enviro impact of the healthy diet is probably lower than an average U.S. diet, even if the % of food waste by weight is higher. 11/
So yes, to reduce your diet's environmental impact, shift toward plant-based foods, eat more fruits and veggies, and of course minimize the food you waste. But don't come away with the message that "healthier diets are less sustainable." There are so many win-wins. FIN.
