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Nutrition & Dieting/Questions about protein deficiency



Let's say there is a hypothetical diet that provides all nutrients in the optimum amount except for protein. This diet does not contain any hint of protein. How long can a 30-year-old male human survive on this diet? What symptoms will he experience as his body id deficient in protein but receives ideal amounts of non-protein nutrients? I've read about kwashiokor's type of protein deficiency but that only affects children, not adults.

Thank you,


ANSWER: Hi Green, interesting question.
First and foremost I would never ever advise anyone to undertake a diet such as this.
I can't give you an exact number but eventually over time you'll experience muscle breakdown.
Without adequate protein intake catabolism or breakdown of the muscles can begin within hours and increasingly get worse. Protein breaks down in the body as amino acids which repair and build muscle tissue. With protein absent the body will not have the necessary "tools" to repair and maintain muscle tissue. Muscle tissue becomes damaged and broken through stress be it lifting weights or regular bouts of strength utilized in your daily activities.

With lack of protein muscle tissue will begin to breakdown within the same day as the absence began. For instance when you sleep your body is forced to fast for around 8 hours. With no intake of amino acids the body actually begins to feed on its own muscle tissue. The same would hold true if you removed protein intake when awake.
Other symptoms would include decreases in strength and energy levels as your muscles are what does work in the body. Furthermore it would seriously reduce function. Look at elderly people who suffer from poor diets. They usually will lose a good amount of muscle tone. This will hinder their strength and ability to do normal activities and general movement.
Furthermore muscle tissue utilizes  calories in the body to repair and do work. This puts your metabolism to work. The less muscle one has the less calories the body uses to maintain life.

You could very likely survive for a while without protein but the adverse reactions it causes will seriously hinder your general health and functionality thus leading to more serious health problems including death. The degree in which muscle will breakdown will depend on the individual and a variety of factors from activity level to body composition.

---------- FOLLOW-UP ----------

QUESTION: Thanks for your response. Is it true that the protein deficiency would also cause the heart rate to slow and blood pressure to drop?

I remember reading a study a while back stating that it was found that supplemental protein drinks could lower blood pressure but not necessarily in already healthy individuals.
Protein does contain the amino acid Arganine which increases nitric oxide production. N.O. opens up blood vessels and allows for a stronger blood flow. The pharmaceutical industry actually sells drugs that do this as well. Then again they usually sell man made drugs that do everything natural compounds can do as well, minus side effects. This could help with blood pressure as the N.O. can help with the elasticity of the blood vessels and promoting a healthy blood flow.  

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Tim Santoro


I can answer questions regarding the following. Confusion about basic nutrition, explain how to improve diet, when and how to eat better, eating for weight loss, eating for health, eating for fitness. I will answer questions about nutritional and workout supplements. I will not endorse any fad diets, however I can explain the draw backs to them and explain why they are the wrong way to go. I will not give advice relating to medications and/or their interactions with food and supplements.


I have earned certifications in Fitness Training and Fitness Nutrition from ISSA. I also self taught and stay current on the fitness industry. I lost 70 pounds training my self.


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