Have you ever wondered about the signs of protein deficiency? Although true protein deficiency is rare, your individual protein needs can vary. U.S. MyFitnessPal users with weight-loss goals get an average of 24.7% of their calories from protein. That falls within the acceptable range of 10% to 35% for adults, but percentages alone don’t show whether someone is meeting their needs—total calories, body weight, age, and activity level also matter (2). Protein is a must-have macronutrient that helps keep your body running at its prime.
“Protein is important for everybody, not just bodybuilders at the gym!” says Melissa Jaeger, RD, LD, MyFitnessPal’s Head of Nutrition. “Your body uses protein for a variety of internal functions that you probably don’t think about day-to-day but are important for your overall health and wellbeing.”
In fact, protein touches just about every function in the body. And while protein may be all the rage, in January 2026, 85% of the 1,000 U.S. adults surveyed say they don’t have any idea of how much protein, fiber, carbs, sugar, and salt they consume daily, based on a survey conducted by MyFitnessPal. (1,2)
Let’s change that — here’s what can happen if you’re noticing common signs of protein deficiency, and how to fix it.
Definition: What is protein deficiency?
Protein deficiency occurs when daily protein intake falls too low to meet your body’s basic needs for tissue repair, immune function, and muscle maintenance. Most adults need at least 0.8 grams of protein per kilogram of body weight per day, while older adults and active people may need more, and protein deficiency symptoms can develop even with mild, chronic shortfalls. (9,18,16,3)
Is Protein Deficiency Common?
Here’s the thing: it’s rare for people in developed countries, like the United States, to experience actual signs of protein deficiency. (23)
“Medical conditions like Kwashiorkor and Protein Energy Malnutrition (PEM) can happen in developing countries when people don’t have enough to eat and are much rarer in developed countries. This isn’t about that kind of clinical protein deficiency,” says Jaeger. (3)
Here, we’re talking about what could happen to your body when you aren’t getting the ideal amount of protein to feel and perform at your best. Rather than diagnosing yourself with a medical condition like protein deficiency, this is more about noticing possible signs you’re not getting enough protein, then making small, realistic changes. Let’s dive into those signs of low protein intake now.
How Much Protein Is Too Low?
There is no one perfect protein target for everyone. Your needs can shift based on body size, age, activity level, health status, and whether you’re trying to maintain or build muscle.
| Group | Recommended g/kg/day | Considered Too Low |
|---|---|---|
| Most healthy adults | 0.8 g/kg/day (9) | Consistently below 0.8 g/kg/day falls below the adult RDA. (9) |
| Adults over 65 | 1.0–1.2 g/kg/day (18) | Below 0.8 g/kg/day is below the adult RDA; below 1.0 g/kg/day may be low for some older adults. (18) |
| Regularly active adults | About 1.0–1.4 g/kg/day, depending on training (16) | Below 0.8 g/kg/day is below the adult RDA; lower intakes may not support training recovery for active people. (16) |
| People in a calorie deficit | Needs vary; protein needs may be higher to help preserve lean mass (2) | Very low calorie intake plus low protein intake may increase risk of losing muscle. (2) |
According to MyFitnessPal’s food logging data, 73.8% of consistent users regularly fall below their daily protein target 3+ days per week.
10 Signs of Low Protein Intake
1. You’re losing muscle mass
Research shows that when your body isn’t getting the protein it needs from food, it will begin to break down your muscle protein to keep your body functioning. (2) It’s one of the hidden but highly impactful symptoms of low protein.
It can be hard to get enough protein on a low-calorie diet. “If you’re cutting too many calories, your body will outsmart you!” says Jaeger. When you’re in a calorie deficit, your body uses stored energy sources, including both fat and muscle, to meet its energy needs. That means, if your goal is to build lean mass, you may not see the results you’re hoping for.
2. You feel fatigued for no reason
Severe protein malnutrition can impair blood-cell production and contribute to anemia, which may cause fatigue and weakness. Fatigue has many possible causes, however, and low protein intake is rarely the only explanation. (4)
“Low protein is rarely the only reason someone feels tired, but it can be one clue that total intake or meal balance needs a closer look,” Jaeger says.
3. You catch every cold going around
Protein plays a big role in immune health. In fact, proteins make up many of the hormones, antibodies, and enzymes involved in fighting off foreign invaders, like viruses and bacteria, that can make you sick. (5)
“If you’re finding yourself sick more often than usual, it’s worth taking a look at whether you’re getting enough protein and overall nutrients,” notes Jaeger. That doesn’t mean eating more protein will stop you from getting sick, but it’s a reasonable thing to verify. Logging your meals in MyFitnessPal for a few days can help you spot patterns in your protein intake and see how it lines up with how often you’re getting sick..
4. You get constant cravings
There’s a reason protein is trending when it comes to weight loss: it keeps you fuller for longer, preventing mindless munching and cravings. Research suggests when people aren’t getting enough protein, they may choose less nutrient-dense foods to satisfy their hunger. (6)
If you’re noticing signs of low protein intake like more frequent cravings, it’s worth checking whether each meal includes a protein source, such as eggs, Greek yogurt, tofu, beans, lentils, chicken, fish, cottage cheese, or edamame.
5. Your cuts take forever to heal
Proteins are the building blocks for many parts of your body, including your skin. Collagen is one protein in the skin that’s crucial for wound healing. So if you’re noticing a bruise, scrape, or cut is taking longer to heal, it’s worth checking how much protein you’re getting. (7)
Slow healing is one of the signs of low protein intake that can also be related to diabetes, circulation issues, medications, infection, or other health conditions, so don’t ignore wounds that aren’t improving.
6. Your hair seems thinner or more brittle
Hair changes can happen for many reasons, including genetics, stress, hormones, medical conditions, and nutrient gaps. Malnutrition has been associated with symptoms of low protein like hair thinning and hair loss in more severe forms of undernutrition. (19)
This doesn’t mean protein is always the answer to hair loss. If hair shedding is sudden, patchy, or ongoing, it’s smart to ask a healthcare professional about possible causes.
7. Your legs, feet, or hands look swollen
Severe, long-term lack of protein symptoms include edema, or swelling, because low blood protein levels can affect fluid balance. (20)
Swelling can also be a sign of kidney, liver, heart, vein, lymph, or medication-related issues. Seek medical care if swelling is new, painful, one-sided, or paired with shortness of breath.
8. You have a low appetite or feel weak
Severe protein deficiency symptoms can include weakness, loss of appetite, and reduced muscle tone. (3)
This can become a cycle: eating less may lower protein intake, and feeling weak may make shopping or cooking harder. Simple options like yogurt, eggs, tuna packets, protein smoothies, beans, or ready-to-eat lentils can help bridge the gap.
9. Your skin feels fragile or wounds easily
Protein plays a role in skin structure and repair, and malnutrition can affect the skin’s ability to heal and hold up to everyday wear. (7)
Skin changes aren’t specific to most protein deficiency symptoms, so it’s best to look at the bigger picture: total food intake, hydration, medications, sun exposure, and medical history.
10. You are not recovering well from workouts
Active people often need more protein than sedentary adults to support muscle repair, remodeling, and training adaptation. The International Society of Sports Nutrition notes that many exercising individuals need roughly 1.4 – 2.0 grams per kilogram per day. (16)
If you’re sore for longer than usual, losing strength, or feeling flat during workouts, these may be symptoms of lack of protein you’re experiencing. Check them, along with sleep, calories, hydration, training load, and rest days to ensure optimal health.
Who Might Not Be Eating Enough Protein?
Wanting more protein and actually getting enough of it are two different things. Most people don’t track how much protein is in their food, so it’s easy to fall short without even realizing it. Many overestimate protein in their meals, meaning they might not be hitting their daily protein goals.
There are a few populations who are more at risk than others for not meeting their protein needs, including: (10)
- People over 51 years of age
- People on low-calorie diets
- Those with digestive conditions and/or eating disorders
- People living on low incomes
- People living in food deserts
Protein needs can also rise during recovery from illness, injury, or surgery. If you have a medical condition, work with your healthcare team before making major diet changes.
Easy Tips to Increase Protein Intake
You don’t need to overhaul your whole diet to overcome common protein deficiency symptoms. Start with one meal or snack. Following a balanced eating pattern is a good place to start. (17)
Try these simple tips:
- Add Greek yogurt, cottage cheese, eggs, tofu, or smoked salmon to breakfast.
- Add beans, lentils, tuna, chicken, tempeh, or edamame to salads and grain bowls.
- Snack on nuts, roasted chickpeas, cheese, yogurt, or hummus with whole-grain crackers.
- Use MyFitnessPal for a few days to see how much protein you usually get at breakfast, lunch, dinner, and snacks.
- Spread protein across the day instead of saving most of it for dinner.
- Leverage our “High Protein” recipe collection on the MyFitnessPal app.
Star plant-based options worth adding to meals and snacks:
- 1-ounce almonds: 6 grams (11)
- 1-ounce pistachios: 6 grams (12)
- 1-ounce pumpkin seeds: 8 grams (13)
- 1-ounce hemp seeds: 9 grams (14)
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How Do You Know You’re Eating Enough Protein?
Feeling fabulous? Meeting your goals? Then you’re probably on the right track. Many people want to eat more protein — but as we’ve seen, most don’t actually know how much they’re getting each day.
However, it never hurts to double check if you’re experiencing common protein deficiency symptoms, and MyFitnessPal makes this easy to achieve.
Log your foods over a few typical days to see how much protein you’re getting per meal and per day, then compare it with a realistic target. The MyFitnessPal Protein Calculator can help you estimate a starting point based on your age, sex, activity level, and goals.
If you have kidney disease, liver disease, an eating disorder, pregnancy needs, or another medical condition, ask a registered dietitian or clinician for personalized guidance.
Frequently Asked Questions (FAQs)
- How many grams of protein do I need in a day?
Protein needs vary depending on age, sex, frequency of workouts, and what your personal goals are. The RDA for protein is set at 0.8 grams/kilogram of body weight per day.But most individuals who work out regularly need roughly 1.4 – 2 grams/kilogram of protein per day. Using the MyFitnessPal Protein Calculator is an easy and quick way to figure out your own needs to overcome common protein deficiency symptoms. (9,16)
- How do I know if I’m not getting enough protein?
One of the easiest ways to stay on track is to log your meals using the MyFitnessPal app. It automatically calculates the protein content of the foods you eat and shows how much you’ve consumed each day compared to your goal. This makes it easy to spot whether you’re consistently falling short and helps you adjust your meals to include more high-protein foods like eggs, Greek yogurt, beans, tofu, chicken, or fish.
- What happens when you don’t eat enough protein?
If protein and overall calories stay too low, the body may break down muscle and other body protein to support essential functions. Severe protein-energy malnutrition can affect multiple body systems. (3)
- Can low protein cause hair loss?
Severe protein deficiency can contribute to hair thinning and hair loss, but hair loss has many possible causes, including genetics, hormones, stress, illness, medications, and other nutrient deficiencies. (19)
- What causes low protein levels in blood?
Low blood protein or low albumin can lead to signs of protein deficiency like inflammation, kidney disease, liver disease, heart failure, infections, inflammatory bowel disease, malnutrition, or protein loss through urine or the digestive tract. (21)
- How long does it take to raise protein levels in blood?
It depends on the cause. If low blood protein is related to a medical condition, treatment focuses on managing that condition, not just eating more protein. It depends on the cause. If low blood protein is related to a medical condition, treatment focuses on managing that condition, not just eating more protein. (21,22)
- How quickly can you reverse protein deficiency?
It depends on severity, total calorie intake, medical conditions, and whether nutrient replenishment can happen safely. Severe malnutrition needs medical care, since nutrients may need to be replenished gradually. (3)
- What foods fix protein deficiency fast?
No single food “fixes” common protein deficiency symptoms instantly. But protein-rich foods like eggs, Greek yogurt, cottage cheese, fish, poultry, tofu, tempeh, beans, lentils, and edamame can help raise daily intake. For severe deficiency or low blood protein, work with a healthcare professional.
Bottom Line
Protein deficiency is rare in developed countries like the United States, but that doesn’t mean you’re meeting your unique protein needs. If you’re not seeing the progress you’d like in your goals, and find yourself constantly sick, tired, or slow to heal, you may not be eating enough of this powerful macro.
How MyFitnessPal Can Help
If you’re aiming to eat more protein without losing sight of other nutritional needs, the easiest way is to start tracking your food. When you set up your MyFitnessPal account, you provide some information (think age, sex, activity level, and goal) and we use it to give you a customized macro recommendation for protein, carbs, and fat.
As you log your meals and snacks, you can see how close you’re getting to your protein goal and make adjustments. There are also high-protein plans and recipes in the app.
Originally published May 22, 2025; Updated September 21, 2026
The post Protein Deficiency: Symptoms and Signs of Low Protein Intake appeared first on MyFitnessPal Blog.
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