6 signs you’re not getting enough protein

It’s hard to miss the message these days that protein is good for your body. Between wellness gurus constantly talking about ways to get more and grocery store shelves full of protein-packed snacks, shakes, and supplements, it can make you start to doubt your eating habits. So, are you getting enough? The answer may not be super obvious, since a protein deficiency can sneak up on you in ways you wouldn’t expect, from dry skin to bad moods. Here are six signs your body might be asking for more.

Why is protein important?

“Proteins are the building blocks of our bodies,” explains Fernanda Almeida, RDN, a registered dietitian at WeightWatchers. Every cell relies on protein to function, which is why getting enough is so important. It fuels muscle repair, aids metabolism, and maintains healthy hair, skin, nails, and more.

If you look more closely at proteins, you’ll see that they’re made up of chains of amino acids. There are 20 different amino acids in total: Your body can make 11 of them on its own, but the other nine you have to get through your diet. If you don’t eat enough protein, levels of those nine amino acids could dip too low.

What causes protein deficiency?

Protein deficiency is a lack of body protein or a relative deficiency of one or several essential amino acids. While it’s rare in the U.S. and other developed countries, some people still fall short of the recommended daily allowance of 0.8 grams of protein per kilogram of body weight. Older adults, for example, may eat less due to a reduced appetite, or vegetarians may not get enough through plant-based foods.

In some cases, medical conditions can also play a role in protein deficiencies. For example, chronic digestive disorders like celiac disease can prevent proper protein absorption, while illnesses such as kidney disease or liver cirrhosis may lead to excessive protein loss. Severe infections, major injuries, or post-surgical recovery can also increase protein breakdown, making it harder for the body to maintain its supply.

6 effects of protein deficiency

Your body will let you know if it’s not getting enough protein, but the signs aren’t always caused by a deficiency (they might be due to other health issues or just life in general). That said, here are some key things to watch for:

Skin, hair, and nail problems

Protein provides keratin and collagen, which are essential for healthy skin, hair, and nails. A deficiency can lead to brittle nails, hair thinning or loss, and dry skin.

Increased hunger

Studies show that protein is more satiating than carbohydrates or fat, helping you stay full longer. That’s why you might notice that you feel full for longer after a breakfast of eggs compared to a bowl of cereal. If you are feeling hungrier after meals than you used to be, you might not be getting enough protein.

Mood changes

Protein plays a key role in producing neurotransmitters, which regulate mood and mental clarity. A lack of protein can lead to irritability, anxiety, or even feelings of depression, as the body struggles to maintain stable mood levels.

Getting sick often

Without adequate protein, your body may have a harder time fighting off infections and bouncing back from illness. “Protein is vital for a healthy immune system,” says Kristen Smith, RDN, spokesperson for the Academy of Nutrition and Dietetics. “It aids in the production of antibodies — proteins that identify and eliminate harmful attackers like bacteria and viruses.”

Workouts that feel harder

Without enough protein, your body may begin to break down muscle tissue to get the amino acids it needs, leading to a loss of muscle mass. This can make you feel weaker and reduce endurance.

Swelling

Severe protein deficiency can lead to a condition called kwashiorkor, which is marked by extreme malnutrition and swelling, particularly in the belly, feet, and other areas. This condition is rare and primarily seen in children in poverty-stricken regions, where access to adequate nutrition is limited.

How much protein do you need?

The Dietary Guidelines for Americans recommend that adults should consume at least 0.8 grams of protein per kilogram of bodyweight each day. So, if you weigh 200 pounds (about 90.7 kg), that’s roughly 73 grams of protein a day. That said, your protein needs can vary based on factors like medical history, age, weight, and physical activity. “Protein needs should be individualized,” says Smith, who advises working with a registered dietitian to determine what works best for you.

And for anyone losing weight on a weight-loss program or on GLP-1 medications like Wegovy, you should increase your protein to at least 1 gram per kilogram of your bodyweight or more, says Almeida. Getting enough protein can help you hold on to as much muscle as possible while losing weight. WeightWatchers members can now track their protein intake through the app. Just log all of your food into the app and check My Day to see where you’re at for the day.

Hitting your daily protein target doesn’t have to be hard, you just need to prioritize eating foods that are good sources, like lean meat, fish, nonfat Greek yogurt, eggs, beans, and lentils. “Aim to fill at least one-quarter to one-half of your plate with a protein-rich food,” Smith says. And don’t forget about incorporating protein-packed snacks like nuts, cheese, or protein bars into your day.

What happens if you don’t eat enough protein?

In the short term, research shows that eating a diet very low in protein can cause you to eat more calories and gain weight and body fat. If it goes on too long, not getting enough protein can take a real toll on your body. “Every cell in the body contains proteins,” explains Smith. Without a sufficient amount of protein in your diet, you could start to experience swelling, muscle atrophy (loss of muscle mass and strength), hair thinning or loss, brittle nails, and a weakened immune system.

When to seek care

If you’re experiencing excessive hair loss, brittle nails, or swelling in your legs or feet, it could be a sign that you’re not getting enough protein. However, these symptoms can also be linked to other health conditions, so it’s a good idea to check in with a doctor. If you're feeling unusually weak, fatigued, or just not quite yourself, a medical professional can help assess what’s going on and whether your protein intake might be a factor. There is a blood test called the total protein test, which measures two key proteins in your blood: albumin and globulin. The results can help pinpoint whether protein is the issue or if another underlying condition is at play.

The bottom line

Protein is essential for your body, supporting everything from muscle maintenance to immune function. The amount you need each day varies based on factors like age, activity level, medications you’re taking, and overall health. If you’re noticing signs like hair loss, brittle nails, lack of satiety after meals, or frequent illness, it might be a sign that you’re not getting enough protein. Consult with a registered dietitian or healthcare provider who can help you determine the right amount of protein for your specific needs and whether you’re getting enough.