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Things That Happen When You Don’t Eat Enough Protein

Protein is essential to a healthy diet. It's not always easy to make sure you consume enough. Here's what happens when you skimp on protein.

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Your food cravings increase

Having the occasional craving for a snack between meals is normal. But if cravings are constant, and your meals aren’t satisfying your hunger, you might not be eating enough protein. Lisa DeFazio, RD, a Los Angeles-area healthy lifestyle expert, says that’s because protein helps regulate blood sugar. “Protein will slow down the absorption of your carbs—and slow down your blood sugars,” says DeFazio.

When you eat enough protein you’ll also feel fuller longer and won’t have mood swings, says DeFazio. A study published in Nutrition Journal also found that participants who ate a high protein breakfast had fewer “sweet and savory” food cravings. If you need help thinking of ways to eat more protein, here’s how nutritionists sneak more protein into their diet.

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Your metabolism slows down

A low protein diet leads to muscle loss and, as a result, a slower metabolism, says Caroline Apovian, MD, director of the Nutrition and Weight Management Center at Boston Medical Center. “Your resting energy expenditure (REE) will go down because [it] is directly related to how much muscle mass you have,” Dr. Apovian says. The recommended daily allowance for protein is 0.8-1.1 grams per kilogram of body weight, without considering physical activity or calorie intake, according to the National Academy of Medicine.

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Your focus diminishes

Your focus and concentration are low when you skimp on protein, according to Luiza Petre, MD, a board-certified cardiologist and weight loss and weight management specialist in New York, NY. “Proteins make up the hormones and enzymes that allow our brains to function,” says Dr. Petre. “Adequate protein intake ensures the amino acid, tyrosine, is promoting the neurotransmitters that keep us energized and focused.” Here’s how to eat more healthy protein without even trying.

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Your wounds and injuries won’t heal as easily

Protein aids in tissue growth and repair, along with micronutrients, antioxidants, and various vitamins, Dr. Apovian says. But protein is especially critical for oxygen and blood flow to heal and repair the skin, she adds, thus making it harder for low-protein dieters to recover quickly from injuries. Similarly, Ali Webster, PhD, a registered dietitian and associate director of  nutrition communications at the International Food Information Council Foundation in Washington, DC, points out that being protein deficient may lead to a higher risk of bone fractures. “Several studies have demonstrated reduced bone density and increased rates of bone loss in people who habitually consume low-protein diets,” she says.

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You could develop anemia

Anemia is a condition in which the blood doesn’t have enough healthy red blood cells to carry oxygen throughout the body—and there are many different types. Not eating enough protein products high in iron, Vitamin B12, or folate is a common cause. And even people eating who are eating enough protein could still develop anemia if they aren’t eating the right kinds of protein, says Dr. Apovian. Vegans and anyone who is avoiding animal-based protein products are especially at risk for Vitamin B12 deficiency (since the vitamin is exclusively in animal products.) If this is you, you’ll want to read up on B12-fortified foods and B12 supplements. Here are the four traps to avoid when becoming a vegetarian.

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You could suffer from fluid retention

Another symptom of a low protein diet is fluid retention. Dr. Petre says this is because of albumin, a protein in the blood that helps to maintain fluid balance. When your body is lacking albumin, fluid is retained in the extremities, usually the feet. Dr. Apovian notes, however, that fluid retention occurs in rare and extreme cases, often when enough overall calories are consumed, but not enough protein. If you suspect that you’re not getting enough protein in your diet, here’s how to find the best protein powder for you.

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Your nails become brittle and soft

Your body is smart enough not to waste energy on what’s called nonessential processes, Dr. Apovian says. “When you’re not eating enough protein and calories in general, the body is going to shut down and still survive,” she says. This means your nail and hair health fall by the wayside. Dr. Petre adds that this also has to do with keratin, the structural protein that comprises hair, skin, and nails. “While keratin cannot be consumed, eating high protein foods aids in the production of keratin in our bodies,” she says. Check out these complete proteins that aren’t meat.

Sources
  • Lisa DeFazio, RD, healthy lifestyle expert and nutritionist, Los Angeles
  • Caroline Apovian, MD, director of the Nutrition and Weight Management Center at Boston Medical Center
  • Luiza Petre, MD, a board-certified cardiologist and weight loss and weight management specialist, New York, NY
  • Ali Webster, PhD, a registered dietitian and associate director of  nutrition communications at the International Food Information Council Foundation, Washington, DC
  • Bone: “Nutritional Aspects of Hip Fractures.”
  • National Academy of Medicine: "Dietary Reference Intakes: Macronutrients."
  • International Journal of Molecular Medicine: “The Crucial Role of Protein Phosphorylation in Cell Signaling and Its Use as Targeted Therapy (Review).”
  • National Heart, Lung, and Blood Institute: “Anemia.”
  • Nutrients: “Bone Health Nutrition Issues in Aging.”
  • Nutrition Journal: “A Randomized Crossover, Pilot Study Examining the Effects of a Normal Protein Vs. High Protein Breakfast on Food Cravings and Reward Signals in Overweight/obese “Breakfast Skipping,” Late-adolescent Girls.”
  • Nutrition Research Reviews: “Protein Hydrolysates and Tissue Repair.”
Medically reviewed by Samantha Cassetty, MS, RD, on August 15, 2019