“What seems exciting in the store is a lot less so when we get home,” says author Dana Gunders. (Megan Krause/Chronicle Books)

Her “Waste Free Kitchen Handbook” aims to help consumers reduce kitchen waste and save money. (Chronicle Books/Chronicle Books)

If you haven’t thought much about food waste, now is the time. America wastes epic amounts of food: 133 billion pounds worth $162 billion annually, according to the U.S. Department of Agriculture. And consumers shoulder the most blame. Americans toss on average more than 20 pounds of perfectly good food each month. This, while one in six Americans faces hunger.

If, however, you’re already worrying about food waste, you probably have Dana Gunders to thank. Gunders, 37, a food-waste expert at the Natural Resources Defense Council, sparked a national dialogue about the issue when in 2012 she published a landmark report on the subject, shocking and rallying chefs, food manufacturers and government regulators to the cause. (On Sept. 16, Agriculture Secretary Thomas Vilsack announced the first-ever goal to slash Americans’ food waste by 50 percent by 2030.) And what about consumers? After publishing her report, Gunders says she realized that “no one wants to waste food, and yet we do because we didn’t have the information at our fingertips in order to make the right decisions.”

And so, three years later, we have Gunders’s slim but indispensable new guide, “Waste Free Kitchen Handbook” (Chronicle Books, Sept. 2015). In it, she offers up easy, practical tips and delicious recipes that will help reduce kitchen waste and save money. I talked to Gunders, who lives in San Francisco, about her journey and about how home cooks can get started. Edited excerpts follow:

Why do we waste so much food?

There are a lot of reasons, but I think a big issue is that we’re very aspirational when we are shopping. We have grand plans to eat healthy and introduce our children to new types of food or try a new recipe. But when it comes down to it, we like to eat what we like to eat. We want to make things that are easy and we know how to make. Buying different foods stretches us. What seems exciting in the store is a lot less so when we get home — especially on Wednesday night, when you worked late and your kids are hungry.

So true. Planning is key, right?

Absolutely. And I would know. I’m a terrible planner! To stop wasting food, you either need to plan or you need to take up other strategies that make up for the fact you don’t plan well. They include acknowledging what I call “lazy nights,” nights that inevitably you are not going to cook; or being creative in your kitchen to use up things in the fridge. Another one is knowing your food, and by that I mean finding ways to cook or eat it even when it’s not perfectly fresh.

In the book, you have a lot of tips about making foods last longer so you don’t have to throw them out. Give us some examples.

One of my favorites is that you can stand asparagus in a jar of water in your fridge; it will last for a week or two. And did you know that the two drawers in your fridge are designed to create different humidity zones? So you can put things like greens, lettuce, broccoli and carrots in a high-humidity drawer and things that tend to rot and get overripe, like mushrooms, peppers and ripe peaches, in the other, low-humidity drawer. Some drawers have a lever you can adjust, but if yours doesn’t, you can just leave the low-humidity drawer open a crack to let the ethylene gas escape.

The freezer is your friend, too.

There is so much you can freeze that people don’t think of. Like milk. If you still have some milk left when you go on vacation, you can freeze it, then take it out and have it for your coffee that Monday morning you’re back when you haven’t yet gone to the store. Canned tomatoes are another good example. So often you open a can of tomatoes and only use half. Freeze the other half and use it next time.

Among the recipes, you have one for sour-milk pancakes. I love that because I’ve noticed in Nordic countries, they actually sell sour milk.

I got the idea for sour-milk pancakes from my hairdresser. It turns out it acts like buttermilk in baking. I started testing it with some milk on or over the edge. It amazed me that you can cook with it and taste nothing. That revulsion when you smell sour milk is so strong, but it totally disappears. It makes this thick, fluffy pancake. I should add it’s also very safe. Pathogens like salmonella or e. Coli don’t thrive in milk. If you drank really sour milk, you might gag, but it won’t make you sick. And when you cook it, you kill any bacteria.

Fighting food waste is obviously important for many reasons. But it’s one more thing for people to worry about in the kitchen. How do you get started?

It sounds cliche, but the important thing to remember is that every little bit counts. You don’t have to [achieve zero] waste for it to be helpful. I think just by being aware of the issue, you naturally waste less. Plus, wasting less also helps you save money. The average American throws away $30 a month in food. Spending that on a movie or splurging on your favorite fancy cheese instead is way better than throwing it in the trash.

Black is a former Food section staff writer.