Daily Protein Requirements

There is still a lot of controversy about the daily protein requirements, and empiric observations have always found individuals who are thriving on either high or low protein.

What seems even more confusing for Joe Sixpack is that apparently both sides claim to have solid research to bring at the table. So let's delve into the available data, and shed some light on this query.

As you may know, US RDI (Recommended Daily Intake) for protein in non-exercising individuals is 0.8g/kg, and it's still believed that this value covers the needs of about 95% of the population.

But would this be enough for somebody concerned with her/his physical appearance?

First and foremost, RDI states clearly that “no allowance is made for the usual stresses encountered in daily living”, so this value doesn't even cover the needs of moderately active individuals.

And barely covering a need, obviously, doesn't mean optimizing nutrition for an improved body composition. Does it make sense?

It's a well known fact that your plan should always include weight training in order to maintain or increment muscle mass while keeping fat under control. You do weight training, right?

Therefore, our educated assumption is that some additional protein is needed to cover the repair of the damaged tissue, and maybe the synthesis of new muscle. The question is, of course, just how much additional protein should you consume under these conditions?

Bear in mind that measuring daily protein requirements is quite an art in itself, and the result is always a mere estimation.

For this purpose, researchers have to carry a nitrogen balance study, and compare the amount of nitrogen going into the body with the amount eliminated.

A positive balance means that protein is stored in the body (amino acids are the only source of nitrogen), and conversely a negative balance means that protein was lost from the body.

Probably the first serious research regarding this matter was conducted by Peter Lemon who suggested a protein intake of 1.2-1.8g/kg (0.54-0.82g/lb).

However, not everybody agrees with his conclusions, and the main argument is that nitrogen balance studies are far from being accurate, particularly for weight lifters.

On the other hand, Joe Millward cautions that muscle gain doesn't really correlate with nitrogen balance. For instance, based on the positive balance of some studies, lean muscle gains of 300g per day should be encountered, which is absolutely impossible for a natural athlete.

Gaining muscle is such a slow process that logically shouldn't require a tremendous amount of protein. Let's say you gain 0.45kg (one pound) per week, which, by the way, would be a great achievement, especially if you are an advanced bodybuilder.

This 0.45kg of muscle contains approximately 100-120g of protein (the rest is water, glycogen and support for the contractile elements of the muscle tissue). If you gain this muscle mass over a 7 days span, the extra daily protein requirements are only 15-18g.

Now, it's important to note that dietary protein is not used with 100% efficiency, so in reality this figure would be more substantial.

Although at this point we don't have sufficient data, if we assume that 3-5g of protein is needed to provide the building blocks for one gram of muscle, then our 15-18g becomes 45-90g - which is a completely different picture.

Also, even of more importance is that muscle gain is not the only variable in this equation. What about the protein needed to repair the damage done by training? As the old metaphor goes, when you train, you dig a hole that has to be filled before building any muscle.

My guess is that the protein needed to “fill the hole”, so to speak, may be greater than the quantity added on top.

At this point we simply don't have enough information regarding this matter because the available studies last around 10-12 weeks, which makes it very difficult to monitor the changes that occur in body composition.

Ideally, for a sound conclusion, the time frame for such a study should be at least one year.

The solution to this debate may come from a protein researcher named Kevin Tipton, who found that a daily protein intake of 2.5-3g/kg (1.1-1.4g/lb) may be needed for long term improvements in body composition.

And although this figure may seem exaggerated, a highish consumption is vital when calories are reduced below maintenance.

In my opinion, a strength athlete could get away with a "moderate" protein consumption (2.0-2.5g/kg) if he/she has already attained his/her genetic potential, and the main goal is long term maintenance.

But if your goal is to improve consistently your body composition, daily protein requirements may go up.

Also, most bodybuilders had always consumed copious amounts of lean protein, and their long term results are an empiric proof that it's better to eat more of this vital macronutrient than not enough.

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