Protein is a critical component of proper nutrition, as it helps with general body functioning and the building of things like muscles, skin and hair. Recommended sources of protein include lean beef, low fat dairy products like cheese, and skinless chicken, according to the Harvard School of Public Health. Adults need between 50 and 65 grams of protein per day. If you ingest low or insufficient levels of protein -- specific requirements vary widely depending on factors like your age, metabolism and daily activity levels -- you may experience several effects, some positive and some negative.
The amino acids that comprise protein are essential for the transportation of oxygen throughout your blood stream, according to Northwestern University. Lower levels of protein can reduce the amount of oxygen available to your system, which may exhibit itself as feeling of tiredness or fatigue.
Your hair is composed mostly of protein known as keratin. If you don't get enough protein, your body may try to conserve what little protein it has by limiting protein output. This can cause hair loss, according to Yale School of Medicine's dermatology department. The department says such hair loss is often seen in people who partake in extreme dieting.
Lowered Immune Functioning
Protein helps keep your immune system running. A low protein diet may cause a weaker immune response, according to Columbia University's health services. This may make you more susceptible to common illnesses like the cold or the flu.
Protein binds with your cells to help keep water inside of them. The National Academies Press reports that low levels of dietary protein can cause bloating of the extremities and the stomach as your cells release their water. This is especially common among malnourished individuals in the developing world.
Less Risk of Cancer
According to a 2006 medical study published in the "American Journal of Clinical Nutrition," low protein intake causes your body to produce lower levels of certain growth factor hormones. Higher levels of these hormones are linked to an increased risk of cancer. Thus, researchers concluded that a low protein diet may have "protective effects" against the disease.
Decreased Body Mass
Proteins are the essential building blocks of your muscles. For this reason, weight lifters and athletes often consume greater -- than -- average amounts of protein. Similarly, a low protein diet can cause muscle weakness and a loss of your body's lean muscle mass, according to Northwestern University.