Since starting my blog, I like to think I have made my views on dietary fat pretty clear. If not, have a read here, here and here.

I've hopefully corrected a few long held misconceptions and busted a few myths along the way.

So, I trust were are all now gaining the wonderful nutritional (and performance) benefits of eating healthy (animal fats), drinking whole milk, and passing on the vegetable oils, trans fats and processed pseudo-foods.

I've also questioned the long held belief in the importance of dietary carbohydrate and even been so bold as to suggest that athletes need not be quite so reliant upon them – certainly not to the percentages advised by many mainstream sources. Indeed performance can be vastly improved (particularly in events lasting over an hour) by becoming LESS reliant on carbohydrate and (re)training our bodies to be more efficient at burning fat - and to do that you gotta eat it!

“Oh but you can get away with eating so much fat because you train so much – it doesn't apply to normal people!”

I hear this all the time, and let me lay this one to rest.....

YOU...ARE...WRONG

The reality is, if I trained less I'd eat MORE fat and even FEWER carbs. My training allows me eat more CARBOHYDRATE, not more FAT!

So what about protein?

So far, this macro nutrient has flown below the radar on my blog but today it gets it's 15 minutes of fame!

I'm gonna opt to delicately side step the ethical debate around meat consumption. I'm just going to assume that we all support the fact that we NEED protein and accept that people have the freedom to choose where that protein comes from. I respect ethical vegetarians and vegans and think their motivations are very noble.

Personally, I don't think the ethics of a vegetarian / vegan diet are quite so clear cut and I consider it a privilege, not a right to eat meat. I do so in a way which I view as ethical and sustainable as possible – choosing, as I do, to eat meat (and animal products) from animals which have lead as natural, and as happy a life as possible. Ok, not quite side stepped, but I leave it there.

So please, don't judge me for being a carnivore – I love animals too....... I just wish they didn't taste so damn good (or were so good for me).

I am also going to avoid getting dragged into addressing the numerous scare stories linking meat consumption to everything from cancer to global warming. This is not the subject of this post and 5 minutes on Google will highlight the massive flaws in ALL of these studies – yes, every single one.

If you are interested, here's another great blog that addresses the shortcomings of these studies.

Suffice it to say that any research grouping “red AND processed meat” into a SINGLE food group, and not allowing for the ratios of other macro nutrients being consumed, is not worth a second of your valuable consideration. Grass Fed Rib Eye and Billy Bear Ham are about as alike nutritionally as Jersey Butter and used Engine oil...... or margarine.

Really NOT the same thing!

No, this post is more about Protein as a macro nutrient, what it does for us, and critically how much we should consume and when. True to form, I'll also be donning my myth busting pants as well!

So queue the superhero music...... I need to find a phone booth!

So What is Protein Exactly?

“Protein” is often the catch all phrase used to describe a particular macro nutrient we obtain from our diet. To be accurate, this is “Dietary Protein” and we get it from many different sources in different quantities and qualities (more later).

Contrary to popular belief, humans do not use dietary protein directly. As an example, If I eat a steak – the protein content does not go straight to my muscles for repair like some sort of car body filler.

No, as with most dietary science, it's a little more complex than that – but brilliant in it's design.

Dietary proteins (like all proteins) are biochemical compounds consisting of one or more repeating chains of amino acids known as “polypeptides” - this is important, because it's the amino acids which are critical!

There are 22 amino acids which we need to worry about 13 of which we can make or “synthesise” ourselves, 9 of which we cannot (10 for children as they are unable synthesise the amino acid Arginine). These 9 (10) amino are known as “essential amino acids”.

As a side note – you'll often hear textbooks and some nutritionists / dieticians speak of 20 amino acids and 8 essential amino acids.

Strictly speaking there are another 2 (at least) “non-standard” amino acids which are genetically encoded for humans, these are Selenocysteine and Pyrrolysine – but I'm maybe splitting hairs.

20 or 22 - to fully understand this, you'd need to arm yourself with a degree in biochemistry or read this article – be warned, this article WILL make your brain hurt.

Thankfully, the scientific minutia is not all that important. What IS important is the notion that some protein sources (mostly animal based) contain ALL the amino acids the human body needs, other sources DO NOT (mostly plant based) and so must be combined to provide a “complete protein”. A complete protein is one that provides at least the 9 (10) essential amino acids (in sufficient quantity) from which all others can be synthesised.

Dietary protein can therefore be viewed as a model made of Lego bricks. With the individual bricks representing the individual amino acids.

Now, I might want to build a Lego car – but my sister has just built a little house for her dolls.

I have absolutely no use for a dolls house. (In the same way I have no direct use for a cows gluteus maximus)

No bother, I can “break down” her dolls house (most probably violently) and rebuild the Lego bricks into whatever I want – in this case a car.

Providing the model of the dolls house contains ALL the building bricks I need, I can build whatever I want.

If it doesn't, I may have to destroy the Lego fairy castle she's built as well (Seriously, leave my god damn Lego alone!!)

So this is exactly how the human body uses protein. We consume it in what ever form we fancy, we break it down into individual amino acids and “re-build” them into whichever proteins WE as humans need – Providing the original dietary protein source contains all the “building blocks” or amino acids we require.

This ladies and gents is “Protein Synthesis” - pretty neat eh?

So hopefully you can see, if you are consuming incomplete proteins due to a poor diet (I'm not saying vegetarian or vegan – but these diets DO make it harder to consume complete proteins), then you will not be able to synthesise the various proteins your body requires. Like the child with only a modest supply of Lego bricks who can only build lame stuff like aeroplanes with only one wing rather than cool stuff like spaceships!

So, lucky for those of us who consume animal products, meat, fish, poultry, cheese, eggs, yogurt, and milk as these are all fine sources of complete protein.

Unlucky for vegetarians and vegans most plant based foods are not. Even sources which do contain all 9 (10) essential amino acids (like Quinoa) they typically do not contain them in sufficient quantity to be considered “complete”. The may have what is know as a “limiting amino acid”.

Worse still, the many meat replacement products which do provide complete protein (soya products, Quorn etc) also have many negative health consequences to boot. (I'll save that one for another day – the vegans out there probably already hate me)

Of course, the vegetarian diet can be very healthy - it fact, in many ways it's much healthier than the typical Western diet. Vegetarians do actually seem to care what they eat at least!

The best way of providing enough high quality protein in the vegetarian diet is to include meat.... sorry I mean fish! Including fish (particularly oily varieties like mackerel) will also boost Omega 3 intake.

Vegans - seriously, best of luck, but I guess you'll be eating a whole lot of soya and beans / pulses / grains. Sadly these are not foods I would advise anybody to eat in large quantities if health is your ultimate goal. But each to their own.

Bottom line, if you don't eat animal products, you need to be very vigilant in obtaining your protein from a wide variety of different sources, ideally at every meal.

What does Protein do exactly?

“It helps us grow, build and repair muscle” is a fairly standard response but only represents a tiny fraction of what Protein does.

The importance of Protein is best summarised by saying it participates in virtually every process within cells. To this end we should not consider protein as a single compound but more as a number of many different compounds each one dedicated to performing different roles within the body.

So, from our supply of amino acids (derived from dietary protein) we are able to synthesise our own proteins for whatever role may be required.

These roles include....

Defence

Certain proteins, in the form of antibodies, provide defence by immobilizing foreign invaders so white blood cells can destroy them.

Muscle Contraction

The proteins Actin and Myosin are involved in muscle contraction and movement.

Biochemical Catalysts

These proteins facilitate and / or speed up chemical reactions within the body. For example, Lactase breaks down the sugar found in milk.

Hormones

Some proteins serve as chemical messengers to help to coordinate certain bodily functions and activities. You'll all have heard of one...”Insulin” is a hormone protein which regulates glucose metabolism. Another important ones for athletes is is Somatotropin, a growth hormone which stimulates protein production in muscle cells.

Structure

These proteins include Keratin, Collagen and Elastin. They are fibrous and stringy and provide support and strength for hair, nails, tendons and ligaments.

Storage

These proteins store amino acids allowing our bodies to draw on them as required to synthesise other proteins. This includes a protein you've probably heard of – casein (milk protein).

Transport

Carrier proteins move molecules around the body. An important example is hemoglobin which transports oxygen through the blood.

So protein is NOT just the preserve of athletes, gym junkies or body-builders. I'd strongly recommend including it in the diet of anybody who enjoys being alive!

So how much do we need?

Tricky ones this.

We could ask, “Well how much can I actually use?”

To which the answer would be – “It depends on how much you need!”

So kind of a catch 22 and there is the problem. Protein requirement varies from person to person based on genetics, gender, size, age, activity and stress levels, training goals etc.

You'll hear anything from 0.8g – 2.0g of protein per Kg of body weight.

The needs of a small, sedentary female, will differ from those of a large male engaged in heavy strength training which in turn differ from the needs of the elderly.

In this sense – if the body needs it, it'll pretty much take what you can give it! (within reason)

This needs some nuancing though.

I'm sure many of you have heard the proposition that we can only “absorb” 20-30g of dietary protein in one sitting. If a anybody tells you this they fundamentally misunderstand how protein is assimilated by the human body. As dogmas go, it ranks right up there with myths like “Saturated fat clogs your arteries”, “High Cholesterol causes heart disease” and “Athletes need to base their diet on 60% carbohydrate”.

Before we look at the science, lets consider this notion from a logical, evolutionary perspective.

Imagine if you will one of our Palaeolithic ancestors. Now, it is generally agreed that “paleo man” ate a heavily animal based diet – up to 65% total calories in fact (with the rest coming from plants).

So it can be taken as a given that our ancestors would have consumed a fair amount of dietary protein and fat (also less total carbohydrate, definitely MUCH LESS sugar and definitely ZERO “Weight-watchers “ lasagne).

See here: Hunter Gatherer Diets

Also, before the benefits of shops and refrigeration or other means of preservation, food would have been consumed more sporadically, eaten as and when it was available, most likely during large single feeds and interspersed with periods of enforced fasting. The human body evolved to operate in this way, as did those of most other animals. Indeed, intermittent fasting or “IF” has a large following amongst those looking to maximise health and longevity.

It would seem a pretty serious flaw in the human design if, having taken a number of days to bag a decent meal our paleo ancestor would only be able to make use of a mere 30g of dietary protein it contained?

I'm guessing a fully grown active caveman could need (conservatively) around 100-150g of protein per day. So the lousy 30g “hit” from his meal would see him becoming quickly protein deficient and pretty quickly dead – along with the rest of his species.

No, luckily for us the human body is far more elegant than that. Larger, protein rich meals (which are also likely to also contain significant amounts of dietary fat) will take longer to digest.

This is key, we don't eat pure protein or amino acids (unless we supplement) – we eat REAL food!

Also, the presence of protein in the duodenum causes the secretion of the peptide hormone Cholecystokinin which slows the intestinal contractions – giving yet more time for amino acids to be absorbed. Hey, it's almost like the body actually knows what it's doing and isn't deliberately trying to kill us!

So yes, while it may take time, ALL the protein you eat WILL be broken down into amino acids and absorbed. Remember, absorption only refers to nutrient uptake via the digestive tract and the fact is, our bodies have a very large capacity for amino acid absorption. Now amino acid UTILIZATION is a different story and this is probably where a lot of the miss-information comes from.

As I've explained amino acids serve many different roles within the body. But what about the specific benefits to athletes and sports people?

Muscle building

For endurance athletes this doesn't mean getting huge biceps and pecs (sorry). Genetics and body type will largely dictate if you are likely to “bulk-up” with training and diet – even if you lift big weights (which you should) - Natural endurance athletes (ectomorphs) are less likely to bulk up than naturally bigger people (meso and endomorphs). However – this doesn't mean endurance athletes can't build lean muscle and get very lean and very powerful – because we can!

So for endurance athletes combining protein with training is about building new, lean muscle mass, losing excess body fat and increasing our strength and power to weight ratio.

Oi fatty!

Exercise adaptation

This means becoming stronger or more efficient as a result of training. Diet (and specifically protein) supports this. It may be by producing more muscle tissue, but equally it may be through producing more mitochondria (energy cells) or new oxidative enzymes – to improve aerobic capacity.

This underlines the importance of protein intake after ALL types of training, not just those deemed to “damage muscles” as traditional dogma would dictate. The way and type of protein which is synthesised depends on the nature of the training stimulus.

Recovery

Recovery is of course a critical component of training. It's during recovery, NOT TRAINING that our bodies become stronger and more efficient than they were before. Training (and racing) causes damage at the cellular level. Without adequate protein, recovery from training will be impaired . This not only limits subsequent training (and adaptation) but also increases injury risk.

Above all, we want to make sure we are supplying our bodies with enough dietary protein to maximise muscle protein synthesis, and support exercise adaptation and recovery.

To achieve this, the rate of muscle protein synthesis (from amino acids) must be elevated above baseline (and above the rate of muscle breakdown). How much dietary protein do we need to achieve this?

Again, we need to look at amino acids. Studies have suggested that around 15g of essential amino acids are required to optimise muscle protein synthesis. Critically however, not all amino acids are equal and it seems that the amino acid Leucine has a more significant role to play. It has been shown that Leucine stimulates a compound in muscle known as mTOR or the rather wordy "Mammalian target of rapamycin" which is like a molecular "switch" which drives muscle protein synthesis. 15g of essential amino acids will typically yield around 3g of Leucine. So we need at least 3g of Leucine – how can we get this?

Well, 30g of Whey protein powder would do the job (less if you choose to add extra Leucine), but if you are using a food source you might need anything up to 40g if beef or fish was you protein of choice.

So, protein is doing it's thang – how long will this effect last? This will also depend on the nature of the protein source. Science seems to agree that protein synthesis will last around 2 hours following ingestion of a (whey) protein supplement and maybe 3 hours following food.

What's interesting is that protein synthesis seems to stall beyond this time frame, even if blood amino acids remain elevated. It can be said that protein synthesis becomes “refractory” or no longer responsive to elevated blood amino acid levels beyond a 2-3 hour period. A real shot in the eye to anybody advising a “grazing” dietary approach or one recommending protein intake should be spread out across many small meals. (including the gym junkies who neck a protein shake every 2 hours!)

A rat study by Wilson G, Layman D et al showed that once again Leucine had a role to play. Here it was found that Leucine supplimentation 2hrs after training (and initial protein intake) could extend the protein synthesis window or reactivate protein synthesis once it had become refractory to circulating blood amino acids. I am not aware that this study has been conducted in humans yet, so consider these results with caution.

Generally speaking though, it seems a “reset” is required and blood amino levels should be allowed to return to near base line levels before another bout of protein synthesis can be initiated with a protein feed.

Contrary to nutritional dogma then, it would seem our protein intake is better coming from 4-6 larger protein doses with 4 to 5 hours in between rather than lots of smaller doses with snacks and shakes etc.

This notion is supported by a great deal of research looking at both intermittent fasting diets and uneven protein feeding diets.

The study below had subjects eating ALL their daily food intake in one meal – pretty extreme my modern standards. However, the subjects did not become protein deficient (which they surely should have if we are to believe the 30g protein per meal limit). They DID however become leaner and had lower cortisol levels (the bodies stress hormone)

A controlled trial of reduced meal frequency without caloricrestriction in healthy normal-weight, middle-aged adults

This next study looked at elderly ladies who consumed dietary protein either split equally throughout all daily meals or taken as a large protein feed during one of their main meals.

Protein synthesis was significantly improved in the group consuming their daily protein intake in a single meal.

Daily protein intake was still within the “normally” advised range, but the elderly subjects benefited from the single higher “dose”.

Whether this benefit was due to the single feed or just the higher dose is hard to say. Maybe the split feeding did not provide enough protein to meal to optimise protein synthesis?

However, we CAN say that higher protein doses are not just tolerated – they are beneficial,

Protein pulse feeding improves protein retention in elderly women

So hopefully the nail is well and truly in the coffin of the “20-30g protein per meal” dogma

Daily requirement remains hard to quantify though. I would view the generally publicised range of 0.8-2.0g per Kg body weight as a minimum but would suggest elevated levels could be optimum - or more beneficial from a health / body composition / performance stand point.

The basic protein needs of a sedentary individual could probably be met at the lower / mid point of this scale by consuming real foods containing high quality protein (ideally animal based – sorry). But even this group may benefit from increasing protein intake (more later).

Those engaged in heavy training should definitely push intakes towards the 2g/kg level and will not experience negative health connotations (providing the individual is in good general and renal health and does not choose potentially damaging protein sources like soya).

Very big males wanting to build significant size and strength could even push beyond 2g/kg without ill effect.

But do remember, just because you may not be “working out” regularly, don't think you have no use for dietary protein. You do of course, as this blog has hopefully made clear by highlighting the many roles protein plays beyond simply “muscle building”.

Indeed, there may be another reason to increase protein intake amongst sedentary individuals

That being “Satiety” – or satisfying hunger.

Anecdotally, higher protein diets have been shown to satisfy hunger but the mechanism has been largely unexplained.

However, recent research has shown that satiety and food intake is modulated (in part) through special receptors (known as mu-opioid receptors or MORs) on nerves found in the walls of the portal vein.

The portal vein drains blood from the gut. So, stimulating these receptors enhances food intake, blocking them suppresses intake.

And what do we think protein does?

Yup – you guessed it. Protein, or more precisely peptides, (the products of digested dietary protein) block MORs, blunting appetite. These peptides then send signals to the brain which transmits signals back to the gut to stimulate the intestine to release glucose. This then suppresses the desire to eat.

Add to that the fact that animal protein often comes with a good source of healthy fats and you can start to see why a breakfast of bacon and eggs will satisfy hunger far more effectively than a “real world” serving of Special K! (And could be lower in calories as well!)

Another reason to consider increasing your protein intake is if weight loss or improved body composition is your goal.

A great (recent) study here showed that during a 12 month, calorie restricted diet, when protien intake was increased from the accepted norm of 0.8 g/kg to 1.6 g/kg a greater percentage of fat mass was lost and more muscle mass was maintained.

Interestingly, both high protein AND low protein groups did lose the same amount of weight but the lower protein group lost more muscle (and less actual fat) – not good.

This illustrates the problem with many conventional weight loss regimes which limit protein and fat in favour of carbohydrate (often poor quality). These diets do often yield weight loss (mostly by extreme calorie restriction) and people who follow them may even deem their “diet” to have been a success. Until, that is, they try to maintain this restrictive eating regime and realise it's just not possible. When they do eventually “fall off the wagon” the lost of precious muscle mass (and the preference for their bodies to burn sugar and store fat) will mean the fat very quickly returns.

The so called “yo-yo” diet ensues.

So why does protein consumption cause this preferential (and more likely permanent) weight loss? Well not only does dietary protein require more energy to break down than carbohydrate (increased thermogenisis), having more muscle mass increases your energy requirement at rest (increases BMR) so you burn more calories doing nothing!

Also, lower protein intakes most often mean higher carbohydrate intake (to obtain sufficient calories). Higher carbohydrate intakes (particularly of the refined sugary types) keeps insulin elevated which “locks in” fat as opposed to burning it as fuel. Higher protein diets on the other hand typically have lower carbohydrate percentages and higher fat percentages. Consuming fat does not trigger insulin, so our bodies adapt to becoming efficient fat burners.

So if weight loss is your goal (even for athletes) it's far better to keep good fats in the diet along with protein up to 1.5 – 2.0 g/kg and introduce strength training into your regime. That way, lean muscle mass will be maintained – even increased and you will become a lean, fat burning machine!!

Oh, an your food will taste good – which is a bonus!

Is there a flip side?

It would be remiss of me to extol the many virtues of protein intakes, which may be higher than those deemed appropriate by many main stream sources, without discussing any negative health issues.

Some would warn of the potential damaging effects of too much protein as this is said to place excessive stress on the kidneys.

Ok, “stress”. It's an emotive word.

Dead-lifts “stess” our back and other muscles, but this is what our back and other muscles are designed to do – lift heavy shit!

It's the same with our kidneys. Higher protein loads do “stress” our kidneys – but it's what our kidneys are designed to do – handle fluctuating protein loads.

It's like advising people not to breathe too hard because it stresses the lungs. Or think to hard because it stresses the brain!

Same applies to kidney stones. Increasing protein intake will not increase your risk. Again, it seems a pre-existing metabolic dysfunction is required before dietary protein can increase risk of stone formation.

No, in a healthy individual, with healthy, functioning kidneys, the idea that higher protein intakes come with increased risk of kidney disease is just not supported by the science.

Conversely, the notion that higher protein intake DOES NOT increase health risks, in healthy individual, IS supported by the science.

Dietary protein intake and renal function

High protein diets decrease total and abdominal fat and improve CVD risk profile

Bottom line – healthy individuals need not be concerned.

So with that, it's over to you all.

Consider your age, size and training / weight loss goals. Consider that for most of us, the lower end of the generally accepted range is too low and there are significant benefits to increasing protein consumption.

Consider splitting your (increased) daily protein intake across your 3 main meals and your 1 – 2 post workout recovery supplements. If anything, aim for 4-5 higher protein doses with more time in between, as opposed to “grazing” or multiple feeds with lower single protein doses.

Following this regime (and incorporating heavy weight training into my routine) I have been able to lose significant amounts of body fat and build more lean muscle.

Ok, so I've never been a fatty exactly, but I'm a stronger and leaner athlete in my 40's than I was in my 20's – FACT.