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Why Do We Need Protein in Our Diet?

by Elle Paula

About Elle Paula

Elle Paula has a Bachelor of Science in nutrition from Framingham State College and a certificate in holistic nutrition from the American College of Healthcare Sciences. She is also a licensed aesthetician with advanced training in skincare and makeup. She plans to continue on with her education, complete a master's degree program in nutrition and, ultimately, become a registered dietitian.


Protein belongs to a class of nutrients called macronutrients, so called because your body requires large amounts of them. The proteins in your body perform a number of different functions essential for sustaining your life. To ensure that your body contains the proper amounts of protein to perform these functions, approximately 10 to 35 percent of your daily calorie intake should come from protein.

Tissue Support

One of the most important roles of protein is to provide support to all of your body's tissues, enabling you to stand and move. For example, the most abundant protein in your body is called collagen. It is a component of the bones, tendons and ligaments that form your joints. Your muscles contain two proteins called actin and myosin that enable your muscles to work properly.

Fluid and Acid-Base Balance

Blood proteins are essential to maintain fluid balance in your body. Your smallest blood vessels, called capillaries, contain proteins that attract fluids. These proteins help pull water into the capillaries and prevent fluid from accumulating in your tissues -- a condition called edema. Proteins also help to maintain the proper acid-base balance in your blood. The normal pH of your blood is approximately 7.4. If the pH of your blood changes, even slightly, it can lead to life-threatening conditions. Proteins act as buffers in your blood. If your blood becomes acidic, proteins can remove excess hydrogen ions. If your blood becomes too alkaline, proteins can release hydrogen ions.


Your body contains a type of proteins called transport proteins that attach to nutrients, waste products and electrolytes and carry them through your blood. Other types of proteins form openings, or pores, in your cell membranes that allow sodium and potassium to travel in and out of your cells when necessary. Lipoproteins are complexes of fats and proteins that carry dietary fats from your small intestine and fats made in your liver to other tissues for energy or storage.

Immune Response

When your body comes into contact with a foreign substance, such as a bacterium or virus, your immune system creates and releases proteins called antibodies. These proteins attach to the foreign invader in an attempt to neutralize it and prevent it from causing a disease or infection.


Because protein contains about 4 calories per gram, it can serve as an energy source when needed. However, since protein has so many other vital roles in your body, you should not rely on it to meet your energy needs. Your body prefers to obtain energy from the carbohydrates and fats in your diet.

Photo Credits:

  • slice of multigrain bread and peanut butter image by Aussiebloke from Fotolia.com

This article reflects the views of the writer and does not necessarily reflect the views of Jillian Michaels or JillianMichaels.com.