When it comes to talking about food, there’s no escaping macronutrients: carbohydrates, fats and proteins. These are the building blocks for any diet, and they’re worth paying attention to—whether you’re trying to lose weight, build muscle or just stay healthy. But while most people tend to immediately focus on carbohydrates, protein is becoming more and more of a hot topic.

What do the Atkins, Keto and Paleo diets all have in common? Aside from being hugely popular, they focus chiefly on protein intake. Carbs are left out of these diets by default, so most people spend their time monitoring their protein intake instead of counting calories. It brings up an important question. How much protein do we really need each day?

Why is protein so important?

Before looking at how much protein a person might need every day, let’s take a step back and look at why it’s important.

As one of the three essential macronutrients, protein’s role in your diet is prolific. Your body breaks down protein for a broad range of uses—everything from muscle recovery to hair and nail health to replenishing your natural antibodies and more. Without protein, your body would become weak and frail, unable to carry out many of its natural processes. People suffering from a protein deficiency often have sallow skin, brittle hair and exhibit general lethargy.

It’s not an understatement to say that protein is essential for life. That’s why so many new diets make protein a focus. You can cut out carbs and your body will learn to burn protein and fat for energy, but you can’t rewire your body to make fats and carbs fill the role of protein.

How much protein do you really need?

Like most health-related questions, the answer to this one depends on the person. The 9-5 desk jockey won’t need as much protein as an ultramarathon runner, who won’t have the same needs as a bodybuilder.

The amount of protein you need depends on several factors:

• Weight: The Recommended Dietary Allowance (RDA) of protein is largely based on weight. All other variables aside, your baseline should be about 0.8 grams of protein per kilogram of body weight. Scratching your head? Multiply your weight in pounds by 0.36 to get your RDA.
• Diet: If you’re on Atkins or Keto or another diet that skews its macronutrient ratios dramatically, you’re going to need more protein. In these cases, it’s best to look at your protein RDA as a percentage of total calories. For example, if you’re on a 70/25/5 ratio (fat/protein/carbs) diet, protein would make up 25 percent of your daily caloric intake. This is likely to be much higher than your RDA by weight.
• Lifestyle: Are you a distance runner? Gym rat? Intramural athlete? Expect to eat more protein than the average person. This can be tricky, though. For runners and athletes, the extra protein typically comes in the form of a recovery meal after strenuous exercise. For bodybuilders, protein shakes and powders often account for the extra. This extra protein is good—your body needs it to repair the damage done during your workout.

Age, gender, ethnicity and even genes also play a role in how effectively your body processes protein and could dictate how much is right for you on a daily basis. The best way to figure it out is to start with your baseline RDA—either by weight or by diet—and factor in your lifestyle. If you are concerned about your dietary balance, speak with your doctor.

Is there a such thing as too much protein?

It’s very unlikely that you’ll eat too much protein. The reason is simple: protein is filling! It takes our bodies longer to break down protein than it does carbs or fats, which means we feel fuller for longer. You’re more likely to feel stuffed before you over-indulge on protein.

There is one thing to be concerned about with excessive protein intake, however. Your source of protein could impact you in other ways. Eating a juicy steak is an excellence source of protein, but eating one every day can lead to high cholesterol or heart disease. Remember, you’re not only consuming protein—think about everything else in your foodstuffs.

With that in mind, consider good sources of protein and vary your intake each day. Meat and poultry are usually good in moderation, as are dairy products. Eggs, legumes and beans are all great, too. Fish is perhaps the best source of protein—not only because of its high protein content, but also because eating fish also gives your body access to omega-3 fatty acids, calcium and various vitamins. There are also a wide range of plant-based protein sources ideal for vegan and vegetarian diets.

Pay more attention to protein

While most of today’s fad diets emphasize protein, it doesn’t necessarily mean they’ve got it right. Balancing your macronutrients is important. It’s a smart idea to start with protein and build your diet around it. It’s possibly the most important of the macronutrients and the one you’re likely not getting enough of!