6 Things That Happen to Your Body When You Don’t Get Enough Protein

August 23, 2020

by Cathe Friedrich

Protein is one of three macronutrients your body needs for health, the other two being carbohydrates and fat. Carbohydrates and fat are the body’s primary source of energy while protein serves as more of a back-up energy source during times of starvation or stress. However, protein plays other key roles in the human body. It’s also essential for muscle repair after a workout.

Most sedentary people get enough dietary protein, although you need more than a sedentary person if you exercise. In fact, athletes need up to double the amount of protein that someone who doesn’t exercise does. The extra amino acids from protein helps with muscle repair and provides the building blocks for building new muscle tissue.

One way people fall short in their protein needs is when they restrict calories to lose weight. But dropping your protein intake too low has consequences. Let’s look at some things that can happen when you skimp on protein.

You’re More Likely to Snack

Protein is the most satiating of the three macronutrients. When you have a healthy portion of protein with your meals, you’re likely to fill up faster and stay full longer. Dietary protein has the power to curb cravings too. You’re less likely to reach for a sugary snack when you eat a protein-rich meal. That’s one reason diets higher in protein help with weight loss. In one small study, women who consumed a diet higher in protein increased feelings of fullness and boosted key appetite hormones that control appetite. You won’t get that when you snack on processed carbs!

One reason protein fills you up is that it boosts the release of a satiety hormone called PYY. In turn, that helps you get that full, satisfied feeling faster. If you’re currently eating a bowl of cereal for breakfast, switch to a breakfast of eggs and see if you don’t feel those hunger pangs diminish!

You Could Experience Muscle Breakdown

If you’re working hard to build muscle through strength training, you need more protein for muscle repair and to build new muscle tissue. If you’re restricting calories to lose weight, your protein intake can suffer too. In turn, that can lead to muscle breakdown. Your body only uses a small percentage of protein for fuel, but when your body is in a “starved” state, it turns to protein as a fuel source and that protein comes from muscle tissue. Studies show that people can reduce muscle loss when losing weight by consuming more protein and strength training. Also, losing weight quickly is more likely to lead to muscle loss.

Insufficient Protein May Slow Fat Loss

One study involving 130 overweight people found those who ate a diet higher in protein, while restricting calories, lost 53% more body weight relative to those who ate modest quantities of protein. Eating a higher protein diet also helps with weight maintenance after you lose weight.

You also need more protein if you’re trying to lose weight. Getting sufficient protein and strength training ensures that your body loses more body fat than muscle tissue. Plus, your body has to work harder to digest a meal high protein over one rich in fats and carbohydrates. So, you expend slightly more calories when you bump up the protein content of your diet. Plus, there are the satiety benefits of protein. It feels you up more, so you eat less over the course of a day.

Low Protein Can Affect Your Mood Too

You need amino acids from protein to make key neurotransmitters, or brain chemicals, that affect your mood. These include serotonin and dopamine. Not consuming enough can lead to mood disturbances such as depressive symptoms or anxiety. One study of adults experiencing depression found that a third of adults who consumed a diet rich in legumes and fish experienced an improvement in symptoms of depression. Remember, protein is in plant-based foods too and legumes are a good source.

Decreased Resistance to Infection

Just as you need protein to make neurotransmitters that affect mood, you need it to make antibodies that fight infection. Studies also show that not consuming enough protein affects another group of immune cells called T cells that protect against viral infections. When these immune cells don’t work properly your risk of infection is higher.

Thinning Hair

Drastically dropping the calorie or protein content of your diet can also cause hair thinning and hair loss. When you restrict calories to an extreme degree, your hair shifts from a growth phase to a resting phase and you end up with a net loss of hair as your hair can’t replace the hair you naturally shed. There can be a lag time between restricting calories and hair thinning of up to 3 months. The best way to turn things around is to increase the protein and calories in your diet.

Space Out Your Protein

There may be a limitation to the quantity of protein you can absorb at one meal. That amount is between 20 and 30 grams. So, don’t try to get all of your protein in at one meal. Space it out over all of your meals and snacks. Be sure to eat a carbohydrate and protein-rich snack after a workout too. You can get protein from animal or plant-based sources. So, you can get enough even if you eat a vegetarian diet, but it takes planning.

The Bottom Line

Now you know why it’s so important to get enough dietary protein and what can happen if you don’t. Eat a source of protein with every meal and snack and you can avoid these problems. Make sure at least 10% of your total calorie intake is from protein. Most experts believe a diet consisting of 10 to 35% protein is appropriate for good health.

References:

Am J Clin Nutr. 2006 Feb;83(2):211-20. doi: 10.1093/ajcn/83.2.211.
Am J Clin Nutr. 2006 Jan;83(1):89-94. doi: 10.1093/ajcn/83.1.89.
Nutr Metab (Lond). 2012 Jun 12;9(1):55. doi: 10.1186/1743-7075-9-55.
J Am Coll Nutr. 2002 Feb;21(1):55-61. doi: 10.1080/07315724.2002.10719194.
Kaiser Permanente. “Hair Loss Caused by Lack of Protein”
org. “The Connection Between Protein and Your Mental Health”
Crit Care Med. 1990 Feb;18(2 Suppl):S86-93.
com. “A High-Protein Diet Plan to Lose Weight and Improve Health”
com. “Fast Weight Loss May Mean Muscle Loss”