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Will a Lack of Protein Make You Feel Weak?

author image Joseph Pritchard
Joseph Pritchard graduated from Our Lady of Fatima Medical School with a medical degree. He has spent almost a decade studying humanity. Dr. Pritchard writes as a San Francisco biology expert for a prominent website and thoroughly enjoys sharing the knowledge he has accumulated.
Will a Lack of Protein Make You Feel Weak?
A dish of bean stew on a rustic dining table. Photo Credit LukeLuke68/iStock/Getty Images

Protein is an essential part of your daily diet and a critical component of several vital processes in your body. Making up around 15 percent of your total body weight, protein is the major building block of muscle; apart from this, it performs other critical functions, such as transporting various molecules, breaking down toxins and providing structure to cells, the National Institutes of Health explains. Failure to get enough protein in your diet affects these vital processes and leaves you feeling weak and more prone to infectious diseases.

Decreased Muscle Mass

You need protein in order to grow and maintain muscle mass. A lack of protein hinders your body’s ability to create muscle and can lead to a drop in your weight and muscle mass. Besides a decrease in muscular strength, you may also experience frequent bouts of lethargy and fatigue. Children with chronic protein deficiency may fail to gain weight or grow properly.

Gastrointestinal Disorders

If you regularly fail to get enough protein in your diet, your body responds by decreasing its production of stomach acids, Merck Manual Home Edition explains. In addition, your entire stomach begins to shrink as the smooth musculature starts to waste away. These physical changes cause gastrointestinal disorders and malfunctions that lead to decreased absorption of various important vitamins and minerals, including potassium and phosphorus. Due to the lack of sufficient nutrients, you may feel weaker and more fatigued as a result. This may be accompanied by frequent diarrhea, causing dehydration and exacerbating your feelings of weakness.

Weakened Immune System

Your immune system relies on antibodies to fight off infections caused by bacteria and viruses. These antibodies attach themselves to harmful invaders and allow immune cells, or macrophages, to engulf and destroy them. However, since antibodies are proteins themselves, a protein deficiency often has serious consequences for your immune system. Without enough protein, your body’s antibody stores start to run low, leaving you much more susceptible to infection and disease. What’s more, if you actually get infected, the effects are more severe than normal, since your weakened immune system is unable to fight the invaders.


Kwashiorkor occurs from a severe lack of protein. This disease is more common in areas experiencing famine and with a low-food supply, MedlinePlus Medical Encyclopedia notes. In developed countries, kwashiorkor may develop in people with illnesses or those who do not get enough dietary protein, such as elderly patients in nursing homes. Symptoms include fatigue, lethargy, diarrhea, decreased muscle mass, hair changes, rash, swelling and failure to grow. Serious complications may involve shock, coma, permanent mental and physical disability and death.

Risk Groups

Eating a balanced diet is usually sufficient for meeting your daily protein requirements. However, certain groups of people have a higher risk for protein deficiency than others, the National Institutes of Health report. Vegetarians and vegans, who eat little to no animal protein, rely mainly on plant protein. However, since plants cannot provide all the amino acids humans need, vegetarians should make sure they get these from other sources, such as vitamin supplements, beans, or eggs. Older adults are another risk group; a protein deficiency leads to a loss in muscle mass, which can result in a higher incidence of accidents and physical trauma.

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