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 savoury” food cravings. If you need help thinking of ways to eat more, here’s the best sources of protein, according to Canada’s Food Guide.
A low protein intake in your 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.
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.”
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, Allison 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.
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 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 these foods that are high in vitamin B12.
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, check out how to up your protein intake in your favourite smoothie.
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.
Next, learn about the best plant-based sources of vegan protein.