As I move towards wrapping up this series this week, I need to discuss a couple of other topics of relevance to the question of what are good sources of protein.  A good bit of what’s been discussed in other sections was a bit on the theoretical/sciency end of things and I’m going to keep the next couple of topics a lot more applied.

Today I want to look at an issue that I don’t think is addressed as much as it could be when folks are looking at protein source; that topic is the presence (or absence) of other nutrients.  Outside of a few select groups (that often get a majority of their protein from isolated sources such as protein powders or amino acids), most people get their daily protein from whole food sources and whole foods contain other nutrients.  Some of those nutrients may be beneficial, some of them may be detrimental; all need to be considered when looking at protein sources and deciding which are good, bad, or neutral.

By Lyle McDonald: www.bodyrecomposition.com

In What Are Good Sources of Protein? – Amino Acid Profile Part 2, I looked a little bit at both the branched-chain amino acids (BCAAs) and glutamine before examining two distinct pathways by which exercise not only increases overall protein requirements but might impact on the specific amino acid profile needed by the body to support heavy training.

In the final part of this sub-series within the series, I want to look at the final way that training can potentially impact on specific amino acid requirements.  I’ll also touch on dieting at the very end.

By Lyle McDonald: www.bodyrecomposition.com

In What are good sources of protein? – Amino Acid Profile Part 1, I examined the issue of amino acid profile, primarily as it relates to general health and wellness.  My basic conclusion, based on the research is that basically any high quality protein source (and this is eminently true in the modern world where people get plenty of protein from mixed sources along with lots of total calories) more than adequately meet the amino acid requirements of adult humans.

Today, I want to continue that by looking at some issues specific to athletes and those involved in heavy exercise training.  It’s fairly well established that athletes need more protein than sedentary individuals although there is still great argument over just how much is needed.

By Lyle McDonald: www.bodyrecomposition.com

Continuing from Wednesday’s article on What are good sources of protein? – Protein Quality, I want to talk a little bit about the amino acid profile of proteins and how that impacts on the answer to the question What are good sources of protein.

I’m going to actually divide this into two parts to keep it from getting too long.  In Part 1, I’ll discuss some basic concepts and look at how the amino acid profile of various proteins relates to supporting basic bodily function. In Part 2, which I’ll run on Monday, I’ll discuss the possibility that athletes have specific amino acid requirements above and beyond what’s necessary to support basic function.

By Lyle McDonald: www.bodyrecomposition.com

Having finished looked at the issue of speed of digestion in What are good sources of protein – Speed of Digestion Part 3, I want to move onto the next topic that I mentioned in the introduction: protein quality.  I’m going to keep this article as brief as possible, for reasons I’ll explain at the end of the article.  If you want or need more, you can pick up The Protein Book which has a detailed discussion of the issue.

By Lyle McDonald: www.bodyrecomposition.com

Ok, somehow this mini-topic got a little bit out of control (I have a lot to say) so I want to wrap up the discussion on speed of digestion and move into the other topics that go into answering the question What are good sources of protein?

Whole Foods vs. Protein Powders

I finished up What are Good Sources of Protein? Speed of Digestion Part 2 with a short chart showing the estimated digestion speeds of various proteins, including some whole foods.  As someone brought up in the comments, it’s unfortunate that there isn’t more data for whole foods because of the fact that, outside of athletes, most people are eating whole food protein sources, not protein powders, to obtain the majority of their daily protein.

By Lyle McDonald: www.bodyrecomposition.com

Yesterday, in What are Good Sources of Protein? – Digestion Speed Part 1, I looked briefly at the issue of protein turnover and synthesis and then looked even more briefly at the now infamous Boirie study that kicked off the interest in fast and slow proteins.

Summing up, that study found that whey and casein (the two proteins found in milk) digested at different speeds, with whey being a ‘fast’ protein that spiked amino acid levels before dropping (after 3-4 hours), and casein being a ’slow’ protein that raised amino acid levels more gradually but remaining stable for an extended period (7-8 hours).

Of more relevance, the researchers also found that the whey protein stimulated whole-body protein synthesis without much effect on protein breakdown while casein decreased protein breakdown with little effect on protein synthesis; I’d note that there was also an increase in the oxidation (burning for energy) of the whey protein.  Thus whey became known as an ‘anabolic’ protein and casein an ‘anti-catabolic’ protein.

By Lyle McDonald: www.bodyrecomposition.com

In the last article, What are good sources of protein – Digestibility, I examined some basics of protein digestibility and presented data on the gross digestibility of varying proteins.  Summing up, animal source proteins such as meat, milk and eggs show extremely high (90%+) digestion while vegetable source proteins show much lower values.

However, the efficiency of digestion alone is not the only factor which goes into answering the question What are good sources of protein?

Recently (and by that I mean the late 90’s or so), an interest in the speed of digestion and how that impacts on various aspects of human physiology has occurred.  It’s turning out that proteins can digest at fairly different rates and this turns out to affect various physiological processes; the main two are protein synthesis and protein breakdown.  As with the last article, I’m going to talk about these terms in brief before moving onto the main thrust of today’s article.

By Lyle McDonald: www.bodyrecomposition.com

In the introduction to this series of articles, I briefly described a number of different aspects of dietary protein that go into answering the question what is a good source of protein.  I’d mention again that ‘good’ in this sense can only be defined in a context-specific way. The protein that might be a good source under one set of conditions may not be a good source under another.  That will make more sense as I go through the series.

Today I want to talk about the issue of protein digestibility; to keep the length down I’ll save speed of digestion for Part 3 of the series.  Once again I’ll note that much of what will appear in this and subsequent articles in this series is being excerpted or paraphrased from The Protein Book, my complete look at the issue of dietary protein.

By Lyle McDonald: www.bodyrecomposition.com

In recent years, thanks to emerging research, diet books and popular articles, the general public is starting to become aware of something that many athletes (especially bodybuilders) have been saying for a while: higher protein diets are better for weight/fat loss and improved health.  In addition, athletes have long been on the search for nutrients or foods that can improve their performance or their adaptation to the training they put themselves through.

Between those two groups, a question that often comes up is “What are good sources of protein?”

Many websites offer simple answers to that question, generally revolving around whatever protein they happen to sell; the answer, as always, is far more complicated than that. A large number of variables go into the declaration of what a good source of protein is and, as always, what is good in one context may not be good in another.