You’ve heard of a carbon footprint. But thinking about its lesser-known counterpart is becoming ever more urgent

From space, Earth looks like a planet overflowing with water. But only about 0.007 percent is fresh and usable, and even that amount is under threat.

Whether for drinking, cooking, bathing, washing clothes, or other basic tasks, the average American uses around 80 gallons of water a day—but that’s just a fraction of their total usage. There’s an additional 2,000 gallons “hidden” in what one consumes on a daily basis.

It may be strange to think about the water we use yet can’t see. Scientists have made that hidden number visible by calculating what is known as a water footprint. Consider one tomato. Its carbon footprint measures how many pounds of planet-warming gas are added to the atmosphere to grow, wash, pack, and deliver the tomato to you; its water footprint tells you how much water it takes to do the same.

The numbers are staggering. In one day a family of four exhausts enough water to overflow an 18-foot aboveground swimming pool. And the biggest contributor is in what we eat. Almonds, for example, are famously exorbitant: Producing one pound can demand up to 1,900 gallons of water (though California almonds, which constitute most of the world’s stockpile, use a more efficient 700 gallons per pound).

This doesn’t mean we have to stop eating almonds. But we can make smarter overall choices. The best way to reduce your water footprint? Consider eating less red meat. When possible, opt for poultry or ocean-caught fish. Veggies, pound for pound, have lower impact compared to fruit, meat, or nuts. Switching to a vegetarian diet can cut one’s water footprint by about 18 percent; a vegan diet by about 25 percent.

Are the numbers tough to swallow? Maybe. The good news is our food doesn’t have to be. Making small swaps (like peanuts instead of almonds) in your everyday cooking is a simple, long-lasting way to stay sustainable. No one’s asking you to give up everything in one swoop. Instead, think strategically: Try tofu and low-impact proteins at least one day a week; lean heavily on veggies; shape your meals around pulses and legumes. The recipes that follow, which highlight low water footprint ingredients, are a delicious start.