How much protein do you really need?

Guess how much protein is in a juicy, 8-ounce cheeseburger washed down with a milkshake? This single meal contains two to three times as much as most people need per day.

It’s no great surprise that Americans chow down on a lot of protein. We love beef and consume about 67 pounds per capita annually (that’s four times the international average). The popularity of low-carb regimes such as Atkins has also made meat the go-to food for dieters.

In fact, the average person eats about double the amount of protein that their body requires, according to the results of 2007-2008 National Health and Nutrition Examination Survey conducted by the Centers for Disease Control and Prevention.

How to fulfill your daily protein requirement

The human body uses protein to repair damaged cells and to build new ones. Marion Nestle, professor of nutrition at NYU and author of What to Eat, estimates that the average adult man needs about 65 grams of protein a day and the average adult female needs about 55 grams. Some sources, such as the Centers for Disease Control and the World Health Organization say you can maintain a healthy diet with even less.

What does this actually mean in terms of food choices? The National Institutes of Health explains that most people can meet their daily protein requirement by eating two to three small servings of a protein-rich food a day.

Examples of a single serving of protein include:

1 egg

2 tablespoons of peanut butter

2-3 ounces of red meat, poultry, or fish (about the size of a deck of cards)

½ cup of cooked dried beans such as black beans or chickpeas

Whole grains, seeds, and some vegetables also contain protein, so consuming enough is not difficult even if you don’t eat meat. Vegetarians and vegans can easily get what they need by balancing complimentary proteins such as corn and beans or rice and tofu. Nutritionists used to recommend combining foods at the same meal, but research now shows that is unnecessary.

Are there drawbacks to eating more protein?

Eating large amounts of red and processed meats is associated with higher rates of heart disease and cancer, and most nutritionists such as Marion Nestle recommend cutting back on meat, especially on fatty cuts.

However, it’s less well known that your protein choices can have a substantial impact on the environment. Meat and dairy production requires tremendous amounts of fuel, pesticides, and chemical fertilizers, and generates greenhouse gases. The Environmental Working Group’s (EWG) recently published Meat Eater’s Guide points out that if you ate once less burger a week it would be the environmentally-positive equivalent of taking your car off the road for 320 miles.

Meat is also expensive. Not all proteins are created equal — neither at the doctor’s office, nor the cash register. Here’s a comparison of three typical proteins:

Many people find meat to be a delicious and satisfying component of their diet that they don’t want to sacrifice. But if you want to save money, eat a nutritionally sound diet, and are concerned about the impact meat and dairy production has on the planet, consider reducing your consumption.

Reduce portion sizes by eating one less burger or steak each week, or participate in Meatless Mondays by skipping meat (and cheese if you can swing it) just one day a week.

Choose the healthiest protein sources when you can. Beans, low-fat yogurt, and nuts are all high in protein and low-impact.

When you do eat meat and cheese, eat the highest quality that you can afford. (One way to save money is to eat less, but better quality meat and dairy products.) Here’s a guide decoding the labels, from cage-free to grass-fed.