The RDA for protein is 0.8 grams per kg body weight per day.  For a person with 70 g body weight, he should eat 56 grams of protein or 224 kcal from protein every day.  For adults, intake of about 2000 kcal per day is recommended depending up the gender.  That means that a person with 70 kg body weight, the calories from protein in his diet should not exceed 11% of the total.  

Americans now eat more than 15%.  And a popular website run by a doctor who also sells nutrition supplements recommends protein should be more than 22% in a diet with high animal protein and high saturated fat. How many food consumers know the adverse effects of high protein diet (high protein means you have to include a lot of meat/dairy products in your diet)?

According to a review recently published in ISRN Nutrition, higher protein consumption is increasing in popularity.  One reason the author says is that many food consumers do not understand the adverse effects of high protein diet.  The review summarizes findings from research papers regarding the adverse effects of a high meat diet and warns that HIGH MEAT DIET is associated with bone disorders and calcium homeostasis, renal dysfunction or disease, increased cancer risk, liver dysfunction or disease and coronary artery disease.  

It should be noted that cancer and heart disease are the two biggest killers in the United States.  In other words, people eating lots of animal-derived protein are at high risk from dying prematurely.  That probably explains why the lifespan in the United States where Western diet with high meat and high sugar is commonly used is shorter than that in many other industrialized countries, even though the U.S. now spends $9,400 per year or 16.9% GDP on healthcare for each person in the country, the highest medical expenditure in the whole world.  (David Liu, PHD)

Delimaris I.  Adverse Effects Associated with Protein Intake above the Recommended Dietary Allowance for Adults.  ISRN Nutr. 2013 Jul 18.

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