However, as with most inventions, there is a potentially harmful application of these very popular “best” lists. There are situations where need to identify best of something obscures real truth that, quite simply, there is no single best ranking. In other words, best of something is in reality a combination of many things. Within world of nutrition, there arguably is not a more clear – and dangerous – expression of this truth then in looking at protein.

The world of nutrition is not short on “best” opinions for sources of protein. Some camps lobby in favor of whey protein as best, while others advocate soy. Some claim that meat and poultry are best source of protein, while others swear that a plant-based item such as spirulina ranks at top. There are so many opinions – each one claiming to support best source of protein – that consumers are often left less informed after reading a few of them, rather than more educated.

One of reasons that search for best source of protein is so widespread is because of its critical importance within a healthy diet. All bodily functions are aided, directly or indirectly, by protein. In addition to being an essential energy source, protein is a component of every body cell, and among other vital contributions, helps in creation, maintenance, and repair of muscle tissue[i].

Furthermore, it is widely accepted – regardless of view on “best” source of protein – that a complete source of protein is required by all people, regardless of athleticism or mobility. This complete source of protein must reflect all 20 different amino acids that comprise protein. Since body can only create 12 of them through its own synthetic production capacity, 8 amino acids – called “essential amino acids” -- must be obtained through diet[ii].

This is where confusion ultimately lies, and root cause of ongoing confusion. Various groups claim that certain specific food sources, such as whey, milk protein, or calcium caseinate[1], respectively, is single best source of protein. Surprisingly, however, a growing body of research is suggesting that that all of these views are incorrect. Rather, a variety of protein sources is proving to be best.

To sustain effort and delay fatigue, body needs an adequate supply of oxygen and fuel without accumulating waste products, acids or heat. Greater intensity of workout, greater is efficiency required. The capacity of cardiovascular and respiratory systems, fuel stores in muscle, hepatic and renal support systems must all expand exponentially to perform in endurance sports. If any of these prerequisites are not met, internal milieu becomes uncomfortable. Metabolism slows down, to allow excretion of wastes, acids and heat, as fatigue sets in. The aerobic stress of endurance sports provides necessary stimulus for growth and development. The body is ready to build. All that is needed are building blocks-the Proteins.

Given an adequate and appropriate supply of proteins, body remains in a state of positive nitrogen balance. Sufficient protein consumption, along with a high-energy diet also influences carbohydrate and fat metabolism. In well-fed state, with sufficient physical activity, dietary proteins stimulate simultaneous release of growth hormone and insulin. The combined hormonal influence redirects dietary carbohydrate and fat to aerobic muscle fibers where they are stored as fuels for exhausting workouts. The consequent increase in muscle stores of glycogen and lipid allows sustained activity for a longer time. With enough proteins, lean body mass, stamina and performance increase throughout training program.

Proteins and amino acids also directly supply between 1 to 6 % of energy needs during a workout. The proportion of energy derived from proteins increases with intensity of exercise. Given their role in bodybuilding, proteins are too important to be used as fuel and attempts should be made to minimize this percentage. Studies by Bowtell and Tarnopolsky, report that a high-energy (carbohydrate) diet, when combined with an ample protein intake and hydration, has a protein sparing effect under aerobic conditions. However, when protein intake is inadequate, high-energy diet fails to protect proteins from being used up as fuel. Therefore, endurance athletes need to ensure high levels of protein intake not only to supply amino acids for growth, but also to make sure that amino acids don’t get burnt up as fuel.