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10 Warning Signs You're Not Eating Enough Protein

A dietitian reveals the telltale signs that you need to increase your protein intake.
FACT CHECKED BY Olivia Tarantino

It's no secret that protein is an essential nutrient for building muscle mass, supporting healthy weight management, and bolstering the immune system. But protein isn't vital only for bodybuilders and athletes; it should be a nutrient of focus in any nutritious, well-balanced diet. If you want to add more protein to your diet, you might wonder: How much protein is sufficient? And what are the signs you're not eating enough protein? Fortunately, we chatted with Destini Moody, RDN, CSSD, LD, a registered dietitian and sports dietitian with Garage Gym Reviews, who answers these exact questions and explores 10 telltale signs you're not eating enough protein.

Before diving in, let's do a quick refresher from high school biology class. Protein, along with carbohydrates and fats, is one of the three macronutrients your body requires for energy. Once consumed, protein is broken down into amino acids (the building blocks of muscle) your body uses for fuel, building muscle, repairing tissue, immune function, and supporting various essential functions.

Providing four calories per gram, protein's recommended dietary allowance (RDA) for a sedentary adult is 0.8 grams per kilogram or 0.36 grams of protein per pound of body weight. Per the United States Department of Agriculture (USDA), this daily amount equates to roughly 46 grams of protein for women and 56 grams for men.

Now that we've established the significance of protein in your diet and how much of it you should consume daily, read on to uncover 10 surefire signs you're not eating enough protein, according to Moody. And next up, don't miss 16 Easy Ways To Increase Your Protein Intake.

You struggle to put on muscle

fit man lifting weights, how in shape you are in your 40s concept

If you find yourself hitting a plateau when it comes to gaining muscle, it might signal a lack of protein. Muscle growth requires more than strength training alone. Research suggests that consuming between 1.6 to 2 grams of protein per kilogram of body weight is optimal for those looking to build muscle.

"Many people trying to put on muscle mass focus on bulking up by eating as many calories as possible," says Moody. "However, you'll likely become frustrated and gain fat without enough protein in those calories. You'll also notice your strength either declining or not improving if you aren't eating enough protein."

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You get sick frequently

Sick woman on couch

If you constantly find yourself with the sniffles or feeling under the weather, it could mean your immune system is operating at suboptimal levels due to insufficient protein intake.

"Many people don't know that antibodies, the molecules in your immune system that fight off disease, are proteins," Moody explains. "No matter what flu shot you've taken this year, your immune system might be unable to defend itself against illness without sufficient protein."

You're always tired

tired woman holding coffee

"When you aren't eating enough protein, your body needs to get its amino acids somewhere. So, it starts breaking down your muscle mass to meet its protein needs. When enough muscle is lost, this causes weakness and you feel constantly worn down," says Moody. If you're regularly fatigued, you may need to reassess your protein intake.

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You experience mood swings

Depressed Man with Problems sitting alone head in hands on the bed and Crying

Mood swings could be a subtle indicator of a protein deficiency affecting neurotransmitter production. Neurotransmitters are chemicals that allow communication between brain cells for balanced moods.

"A lack of protein can lead to eating too many carbs, and those blood sugar crashes can leave you snapping at your friends and colleagues one too many times for seemingly no reason. Protein also makes up some neurotransmitters in the brain that control mood, so when protein intake is low, your mood may follow."

Your hair and nails are weak and brittle

Woman looking at fingernails

Your hair and nails are made up of keratin, a structural protein that requires amino acids. When you don't eat enough protein, your body can't produce enough keratin for the proper growth, strength, and maintenance of hair and nails. Moody tells us, "Your hair, skin, and nails all maintain their integrity with collagen and keratin, which are both proteins. Eating enough dietary protein keeps your hair shiny, nails strong, and skin soft."

You're always hungry


Studies show that protein is the most satiating macronutrient, meaning it keeps you feeling fuller longer and helps reduce cravings. "Incorporating protein into most of your meals and snacks is a great strategy to feel satiated throughout the day," states Moody. "Try eating protein, fats, and carbs together for a complete meal or snack."

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You have anemia

Doctor checking patient for anemia symptoms

While often associated with iron, anemia can also stem from not getting enough protein in your diet. According to the NIH, hemoglobin, crucial for oxygen transport, relies on protein for synthesis. "There are many forms of iron deficiency, but hypoproteinemia is a condition in which a person has very low protein levels in the blood," explains Moody. "Consuming protein-rich foods on a consistent, daily basis can help with iron deficiency. If you're unsure of what type of iron deficiency you have, it's essential to have more blood work done and consult a registered dietitian or physician."

You're losing muscle mass

muscle loss concept

While losing muscle mass is a natural aging process, it can also signal inadequate protein intake. Regular strength training requires a steady protein intake every day to gain muscle. Research points out that consuming 25 to 30 grams of high-quality protein spread evenly throughout the day is the ideal way to build and maintain muscle mass.

Moody says, "Eating enough dietary protein can help sustain muscle status and prevent muscle wasting or loss. Regardless of someone's goals, maintaining muscle mass should be a top priority for everyone's health and well-being."

You struggle to lose weight

stepping on scale

If the scale refuses to budge, it could be inadequate protein that's sabotaging your weight loss efforts. According to Harvard Medical School, protein has a high thermic effect, meaning it requires more calories to burn during digestion than carbohydrates or fats. "When some individuals don't eat enough protein, they may be hungrier, or less satisfied, which results in consuming other high-calorie items that can, over time, lead to weight gain," says Moody.

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You have weak bones

Holding knee, knee pain

"Protein is not only important for your muscles, but for your bone health as well," states Moody. "Regular strength training, combined with adequate protein intake each day, will positively affect bone status." According to the American Society for Nutrition, several studies indicate that higher protein intakes can improve bone density and reduce fracture risk, regardless of protein source.

Adam Meyer, RHN
Adam is a health writer, certified holistic nutritionist, and 100% plant-based athlete. Read more about Adam
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