Sustainability is a very hot topic in the food and nutrition world these days and for good reason.  Every year, we have about 80 million more people to feed than we did the year before. But of course, the amount of land and water we have to grow food—on this planet anyway—is fixed. 

In order to meet the ever-increasing demand for food, we’re going to need to make the best possible use of our finite natural resources. We need to develop ways to produce food more efficiently. And we need to preserve the long-term health and viability of the environment and do what we can to forestall irreversible climate changes that will make it harder to grow food.

Many of us are trying to make food choices that support these goals and efforts. We’re trying to eat sustainably. And while these efforts are well-intended, I’m not sure they are always well-directed.  As I’ve been thinking about this lately, it seems to me that there are three big factors that contribute to the sustainability of our individual and collective diets—and that one or two of these often gets overlooked.

What Does It Cost to Grow Our Food?

The first factor to consider is how much land, water, and energy it takes to produce various kinds of food and how many greenhouse gases are generated in the process. One of the biggest arguments for plant-based diets is that plant crops use less water and energy and create fewer greenhouse gases than meat and dairy. Shifting more of your calories from animal sources to plant sources can reduce both the carbon and water footprint of your diet.

When it comes to sustainability, this is where most of us tend to focus our efforts, or at least our thinking. We’ve all seen the charts and graphs comparing the environmental impact of plant and animal foods and it really seems like a slam dunk. If you want to save the planet, you need to become a vegetarian … or at least shift your diet in that direction.

The High Cost of Food Processing

But there’s a second factor to consider, and that is the amount of water and energy and carbon emissions involved in the processing of those raw ingredients.  It may take fewer resources to produce a pound of soybeans than it does to produce a pound of milk. On the other hand, it takes a lot more resources to convert a pound of soybeans into a gallon of soymilk than it does to convert a gallon of milk into … a gallon of milk.

Whether you’re turning chicken into chicken nuggets or jackfruit into fake chicken nuggets, food processing uses a lot of water and energy and produces a lot of greenhouse gases.  In fact, according the USDA’s Economic Research Service, food processing actually uses significantly more energy than agriculture.

A diet based on minimally-processed plant foods might be the most sustainable and a diet that includes a lot of heavily-processed animal foods might be the least sustainable. But I wouldn’t assume that a vegetarian diet that includes a lot of highly-processed foods would be that much more sustainable than a diet that includes a mix of minimally-processed plant and animal foods. If we’re concerned about the sustainability of our diets, I think we need to consider both the source of our calories as well as the degree of processing.

The Overlooked Impact of Food Waste

There’s a third factor to consider—one that might actually be the most impactful of all and the one that gets the least attention: food waste.

About a third of the food that we produce never gets eaten; it ends up in the landfill. And if you’re worried about the carbon footprint of your diet, consider this: If food waste were a country, it would be the #3 contributor of greenhouse gasses in the world, right behind the U.S. and China. And that’s on top of whatever greenhouse gases were released during the production and processing of that food.

Although plant foods require less energy to produce, they are wasted at a far greater rate. We consume about 80% of the meat and dairy that is produced, throwing about 20% away. But 50% of the fruits and vegetables and about 40% of the grain that we grow is wasted.

Food waste occurs at every step of food production and distribution—from the farm to the warehouse to the grocery store to our own kitchens. A lot of fresh wholesome produce ends up in the landfill because it’s not cosmetically perfect. A lot more is discarded because it is simply in the wrong place at the wrong time and it’s cheaper to pay for it to be hauled to the landfill than it is to store it or transport it to where it can be sold.

Reducing food waste was the topic of podcast #258, where I offered lots of tips on reducing food waste and readers and listeners added lots more. Since then, I learned about a very cool start-up company called Hungry Harvest.  Every week, these guys are diverting millions of pounds of fresh fruits and vegetables destined for the landfill and delivering them instead to subscribers, who save a bundle and also contribute to reducing food waste. Companies like Hungry Harvest, industry efforts like the Food Waste Alliance, and volunteer initiatives like the student-led Food Recovery Network have the capacity to put a major dent in food waste and the greenhouse gasses it produces so let’s support them however we can.

Sustainability Is a Three-Legged Stool

As you consider how you can contribute to a sustainable food system, I urge you to keep all three of these factors in mind:

• 1) If you get a large percentage of your calories from animal foods, consider shifting the balance to get more of your calories from plant foods. You don’t necessarily have to become a strict vegan in order to make a big difference.
• 2) If you consume a lot of highly-processed foods, consider shifting your choices to include more whole and minimally-processed foods. Not only will you be reducing the carbon footprint of your diet but you’ll probably be improving the nutritional quality as well. (And just because you’re a vegetarian doesn’t get you off the hook here. That organic hemp protein powder and those gluten-free frozen pizza rolls don’t grow on trees.
• 3) Be on the lookout for ways to reduce food waste, whether that means bringing leftovers home from restaurants, keeping track of what’s in the fridge so that it doesn’t spoil, buying “ugly” produce, or volunteering for an organization that works to reduce food waste by redirecting surplus food to food banks and shelters.

Thoughts? Questions? Resources to Share? Post them below or on the Nutrition Diva Facebook page.