Protein is essential.  Proteins are made up of amino acids.  There are 20 amino acids that make up the structural proteins in our body. 9 of them are “essential” meaning that we must ingest those 9.  We can manufacture the other 11.  During digestion, proteins are broken down into amino acids which are absorbed, transported and reassembled in other parts of the body.

A great deal of emphasis is placed on “high protein” diets with plenty of lean meat such as fish, poultry, and wild game.  We are told to eat more protein and food products with “high protein” are marketed as superior. Substituting lean meat for sugary, simple carbs and/or unhealthy fats is certainly a step in the right direction and by comparison, is “healthy” and  is likely where the positive press/hype comes from.  ELM’s position is that while preferable to the “typical American” diet, it is nevertheless, suboptimal and may have some drawbacks.  If we take our lessons from nature, we observe that animals with massive muscle mass and strength such as elephants, rhinosaurous, and gorillas are vegetarians that eat only modest amounts of (plant based) protein.  Furthermore, the   all plant based diet prescribed by Dr Esselstyn and adopted by Bill Clinton has scientifically demonstrated amazing benefits in the reduction of vascular disease and the same diet has produced near olympic caliper athletes.

The dangers of high protein should be understood.  Excess protein form each and every meal is excreted in the urine and in so doing takes calcium with it.  Over a period of years this can result in significant bone demineralization. So while one thinks they are building strong muscles, in fact, they are weakening bones and not really helping muscles at all.  Those with underlying kidney disease can exacerbate those problems with excess protein.

So what are protein requirements.  Probably around 0.8 – 1.2g/lb of lean body weight.  Men needing more than women and athletes more than sedentary.  That translates to about 50-100g/day.  Athletes concerns about “tearing down muscle for energy”  apply only to vigorous exercise(not jogging) exceeding 90 minutes. Protein is a poor source of energy and used by the body only as a last resort.

Healthy sources of dietary protein

Egg whites/whole eggs  - Egg whites are probably natures most perfect source of protein.  All essential amino acids in a highly bioavailable form.
Dairy - 
A credible argument can be made against all milk products, especially pasteurized ones.   That nothwithstanding, Greek strained plain yogurt, cottage cheese, raw/unpasteurized, milk are very convenient sources of protein.
Beans -
Primarily a carb but also a very good source of protein. Lentils are best, followed by black beans.  All are great sources of “slow carbs”, fiber, protein
Nuts -
Primarily a fat source, secondarily a protein source.
Tempeh 
– Compressed, fermented (the only type of soy we should eat) soy beans. Also high in fiber.
Fish -
Cold water fish have highest omega-3 content (wild salmon, sardine, herring)
Poultry
  – White meat
Bison
Lean, grass fed beef
Venison
Whey protein concentrate -