JOHN YANG: About a third of the world's population, that's more than 2 billion people, face food insecurity.

Yet a report from the United Nation highlights another problem.

Food waste.

The UN said people throw away enough food to give each person facing hunger around the world more than one meal a day.

Ali Rogin has more.

ALI ROGIN: Over 1 billion metric tons.

That's how much food the United Nations Environment Program says went to waste in 2022.

That's nearly a fifth of all food produced across the globe.

It's an estimated economic loss of over a trillion dollars, and it amounts to 174 pounds of food person per year.

On top of that, when waste sits in a landfill, it creates methane, a harmful greenhouse gas.

Food waste generates eight to 10 percent of global greenhouse gas emissions.

If that were a country, it would rank third in the world, behind only China and the US.

Dana Gunders is the executive director of ReFED, a national nonprofit that's dedicated to ending food loss and waste.

Dana, thank you so much for joining us.

What do we know about the parts of the world where all this food is being wasted?

DANA GUNDERS, Executive Director, ReFED: Yeah, I mean, what's interesting is that there's really not one part of the world to point to as the main culprit.

It truly is a global problem.

And the data in this report confirms that food waste is not -- it's not just a rich country problem.

And that's new because historically, there's been a narrative that in lower income countries, most of the food is lost on its way to market because they don't have a way to keep it cold and it spoils.

And in higher income countries, it's more lost in our homes or in stores and restaurants.

But that characterization is being flipped on its head.

ALI ROGIN: So you just mentioned a lot of the assumptions about where this food waste comes from.

This particular report only started coming out in 2021.

So is the issue here that the assumptions were once true and no longer are?

Or is it that we just didn't have the information to tell us where this waste was coming from?

DANA GUNDERS: It's really more the latter.

You know, we have not been measuring food waste for very long, and it's still really difficult to do.

You know, we don't have scales on every garbage can or cameras or anything like that.

So just the process of collecting the data is challenging.

And really, in this report, one of the main feats they talk about is they've doubled the amount of data they've gotten on the topic.

ALI ROGIN: Let's talk about who's wasting it.

Where's this coming from?

Households, individuals, restaurants?

DANA GUNDERS: Well, certainly it's happening across the board, but households are actually the largest segment of food going to waste.

And that's true in this report from the UN.

It's also true right here in the US.

That's everything from, you know, the science experiment in the back of your fridge to maybe making too much food and scraping your plate into the garbage can.

In the US, we're about average.

We're actually a little under average when it comes to our household waste.

But when you look at the food service, which is restaurants and university cafeterias, anything eaten out of home there, we have about twice as much waste happening as in other countries.

I think the other thing we've seen is that in relative terms, the cost of food has gone down since, you know, several decades ago.

You know, we might go to the store and five or $0.10 could sway us to pick one product over another, but then we get home and that math kind of goes out the window.

And when we throw away $3 worth of cheese or something, and it's just not quite enough for us to be paying attention to for some people.

And that's true for businesses as well.

When we look at restaurants, for instance, oftentimes the labor is a much bigger cost than the food.

And so it makes sense for them to do things like, say, serve really big portions so that they can charge more to cover their costs.

ALI ROGIN: How linked are the issues of food waste and food insecurity?

In other words, if were to cut down on food waste, would it get to addressing issues related to curbing hunger worldwide?

DANA GUNDERS: You know, the root cause of hunger is not that we don't have enough food.

We have enough food in the world to feed everyone on it.

And so hunger is really a challenge of income and poverty and distribution.

So at its core, solving food waste will not solve hunger, but what it can do is it can provide more food into the emergency food system.

If were to cut our food waste in half, that could add about 4 billion meals into the emergency food system here in the US.

ALI ROGIN: There are some bright spots in this report.

One of the things that was mentioned is that Japan actually has reduced its food waste by 30 percent since 2000, 31 percent actually.

What's being done right on this issue?

And what can other countries learn?

DANA GUNDERS: Yeah, absolutely.

There are bright spots.

I think Japan, you know, they've been working on this for a very long time.

And what we've seen is that it does take time, but also a holistic approach.

Policy has played a very important role there.

They passed a law back in 2001 that, among other things, required businesses to start measuring their food waste so they could really see how much they have and do something about it.

There's a great word in Japanese called matanai, and it really expresses a sense of regret around wasting something and kind of values those resources.

And so I think culturally, they've had a mindset of conservation and efficiency built in, and it's certainly something that we could learn from here.

ALI ROGIN: Dana Gunders, executive director of the national nonprofit ReFED, thank you so much for your time.

DANA GUNDERS: Thank you so much for having me.