In recent years, diet culture in America has heavily emphasized eating high amounts of protein, and today the U.S. ranks among the top in the world for total protein consumption per capita. From a health perspective, there can be sprawling negative effects from eating more protein than the body needs—these can include weight gain, increased risk of heart disease, and undue burden on the kidneys, bones, and liver. But the environmental impact of eating protein in such large quantities is equally as detremental and far reaching.

For starters, whenever we consume more protein than the body can absorb at one time (the amount of which is still under investigation), the excess will be stored as fat and/or be filtered through the kidneys and excreted as nitrogen, a key building block of protein, and shockingly, this is harming American waterways.

Why excess nitrogen excretion is an environmental issue

A recent study out of University of California Davis found that high protein intake amongst Americans is causing excess nitrogen to leach into U.S. watersheds and aquatic systems through wastewater. Seeing as fertilizer for plants is primarily made of nitrogen, excess nitrogen in these waterways, also known as eutrophication, will cause aquatic plants and algaes to flourish.

But many times, the species that flourish are not most beneficial to the ecosystem in question, causing toxic algae blooms and “dead zones” for animals due to toxicity and overuse of oxygen from these plants. This can be devastating to aquatic environments across the country, especially coastal areas. It can also pollute precious drinking water. Excess nitrogen in drinking water is usually in the form of nitrate that when consumed in high amounts can interfere with healthy oxygen transportation in the bloodstream.

The connection between animal protein consumption and climate change

Beyond these glaring issues, the livestock farming industry as a whole is contributing to climate change in a serious way. Livestock production contributes at least 14.5 percent of all total greenhouse gas emissions globally. These are related to the production of livestock feed and other inputs like antibiotics, deforestation for new pastureland, operations of concentrated feeding operations (i.e. feedlots), and methane emissions from the cows themselves (i.e. cow burps). These impacts are most significant for ruminant animals, such as beef and lamb, and followed closely by dairy, pork, poultry, and egg production.

How to reduce the environmental impact of eating protein

Through balancing your intake with the amount of protein your body needs, you can make a meaningful environmental impact on both your locally and globally. UC Davis found that if Americans committed to this change alone, nitrogen releases into U.S. aquatic systems would be reduced by at least 12 percent. Here are some easy tips to get started.

1. Know your protein needs

One of the first steps in reducing the environmental impact of your diet, especially from a protein perspective, is to get an idea of exactly how much protein your body needs. In order to get the completely individualized number here, you’d need to consult with a registered dietitian. But there are some calculation methods that will get you in the ballpark.

One of those is a grams of protein per kilogram of body weight calculation. Most people will need somewhere between 0.8 grams and 1.2 grams of protein per kilogram of body weight per day, depending on activity levels. The average person should shoot for around 0.8 grams. To calculate your needs based on this method, simply convert your body weight into kilograms and multiply by 0.8. You might be surprised by just how “little” this number may seem to you, but that’s kind of the point.

2. Opt for plant protein sources

Eating animal protein sources with lower carbon footprints, as outlined above is a good first step, but better yet, try opting for plant-based proteins. Just some of the options here would include nuts, seeds, beans, legumes, lentils, tempeh, and tofu. Not only are these lower in cholesterol and saturated fats than animal proteins, but they provide some of your daily fiber needs, making them a healthier choice.

There’s also a whole market for alternative meat products out there, from your run-of-the-mill veggie burger all the way to product brands like Beyond and Meati where you can barely tell that you’re not eating ground beef or breaded chicken breast. When it comes to these alternatives, some are definitely healthier than others. Try to choose options with fewer ingredients that you recognize.

3. Consider local, regenerative, or grass-fed aimal proteins

If you’re looking for more sustainable animal-based proteins, try looking for regenerative, local, or grass-fed options. Regenerative agriculture, especially when it comes to raising livestock, involves a process called rotational grazing. This means that the animals are continuously moved from one pasture to another, preventing any one area from being overgrazed. This helps to restore and maintain optimal soil health through continual plant growth and the healthy reintroduction of nitrogen from animal waste.

These conditions will actually sequester carbon from the atmosphere into the soil through healthy plant and root growth while reducing, if not eliminating, the need for chemical fertilizers and processed animal feeds. It also helps to reduce nitrogen runoff from the animals that pollutes waterways, as is often the case with feedlot operations. Plus, it helps rebalance ecosystems and protect vital insects like pollinators. Oftentimes, when a product says grass-fed this is what it means.

On the local front, while not all local meat producers will operate in this way, they are usually engaging in practices that are more environmentally friendly than what you’ll find in the grocery store. Plus, there are fewer emissions associated with transport. But the real benefit to local producers is that you can ask them questions about their production practices.

It should be noted that some studies have found that grass-fed beef does technically release more emissions per pound when compared to grain-finished or feedlot-raised animals because the cow’s lifespan will be longer to reach processing weight and thus it will produce more methane through its lifetime. Also, completely grass-fed animals do require more farmland than the grain-finished. Even so, the overall consensus in the sustainability community is that the benefits and carbon sequestration potential of regenerative farming far outweigh these statistics. Plus, if Americans ate meat in a more moderated way there would be less need for the high amounts of meat produced in our country through feedlots and concentrated livestock operations.

4. Embrace balanced eating

If determining your protein needs seems too complicated, there are other ways to balance your protein intake without having to pull out the calculator. Balanced eating is one way to do this. It entails that at most meals and snacks you’re including a source of protein, complex carbohydrate, healthy fat, and fruit or vegetable. Through eating in a way that is inclusive of all the food groups, you’re ensuring that you’re not eating too much of any one food group while getting a balanced array of both macro and micronutrients. There are some great visualizations of how this should look, one I highly recommend is the Harvard’s Healthy Eating Plate which illustrates a balanced meal plate composed of ¼ protein source, ¼ whole grains, ½ produce (fruits and vegetables), and a side of healthy fat.

5. Shop sustainable seafood

While seafood is both delicious and nutritious, it can be among the most unsustainable protein choices out there. Nearly 90 percent of global fish stocks are over-exploited or already depleted. But there are ways to make more sustainable choices, you just have to ask the hard-hitting questions of your fishmonger.

The method of catch, especially for larger fish, is important as many fisheries will use large wall nets that will catch many more species of fish than they’re after, also known as bycatch. Bycatch, when caught on large scales, will have a huge impact on the marine ecosystem of that area. Whether in discussion with your fishmonger or perusing food packaging, look for terms like pole caught, FAD-free, school caught, free school, and pole-and-line-caught, indicating that the product was caught in a way that minimally impacted surrounding marine life.

Also, give seafood that is lower on the food chain a try. Though they sometimes get a bad rap, sardines, anchovies, clams, mussels, and oysters are all really delicious choices that will have a lesser environmental impact as their fast growth cycles enable them to repopulate more quickly. There is a lot more to be said on this topic, so check out seafoodwatch.org for more information.