“You Shouldn’t Eat So Much Protein”
Top 5 Nutrition Arguments You’ll Have this Christmas
Is it just me or is Christmas the time of year where we recieve advice about diet and training from nearly everyone? Maybe you have had a friend or family member tell you that you are doing it all wrong? If you have I’d love to hear about it. Anyway, here is a run down of the top 5 arguments to have with your friends and family this christmas 😉
Typically the message being passed along here is that too much protein is bad for our kidneys.
Now there is some truth to this, f you have a pre existing kidney problem an excessive level of deamination (the process we go through to rid excess protein) can certainly prove problematic. But what about the rest of us?
What does the research say?
A review paper of a large number of studies on the topic by Martin et al 2005 states;
“We found no significant evidence for a detrimental effect of high protein intake on kidney function in healthy persons after centuries of a high protein Western diet”
So how much is too much? Well depending on our protein intake we will sit somewhere along the sliding scale of deficiency to excess.
Deficiency; A reduction in the building up and breaking down of proteins to all but the essential organs leading to muscle loss.
Accommodation; No gain or significant loss in muscle proteins. Some reductions in physiological processes like a reduction in enzyme production. Basically we are ok but not optimal.
Adaptation: Your protein intake allows for optimal enzyme activity, immune function, muscle and other tissue repair and provides a safety margin.
Excess: We start to break down protein to be used as fuel to a far greater degree and we have gone past the point where muscle building and repair is improved and no greater benefit is achieved through additional intake.
Even if we are in excess, although we are not benefiting from the additional protein it is unlikely to cause us any harm.
This is due to a process called deamination. Deamination in basic terms is the body’s way of getting rid of excess protein. I won’t go into detail here but I can say that the amine group from the protein, plus carbon plus urea is successfully eliminated into the toilet!
So how much should we eat?
There are a few questions here. A hot topic at the moment is how much protein can we actually metabolise and how much can we absorb?
Well, we can absorb around 95 % of the animal protein we eat and about 85% of vegetable proteins we eat. How much we can metabolise in one sitting however is a bit more complicated.
Several relatively new studies (see bottom of the page if you like the nerdy stuff) have shown that muscle protein synthesis or the building of new muscle is not improved by any greater than 20g of protein in a single feeding even in athletic people.
The thing is building muscle is one of the reasons we would eat a high protein diet but there are lots of other reasons to stay relatively high protein.
What about all the other nutrients? Although we are mostly talking about protein above, many of the foods we would eat in order to reach our protein intake like for example meat also have a high number of other nutrients often found to be low in low protein diets for example, creatine, B vitamins and iron to name a few.
Increased nitrogen balance. Earlier I talked about the different levels of protein intake. Again I don’t want to go off on a tangent but nitrogen balance is effected by the amount of protein we consume and the amount of protein we breakdown. Only in the adaptation level can the growth process be accelerated, miss it and miss out.
Improved macronutrient ratio for fat loss. Reducing carbohydrate intake from 3.5g daily per kg of bodyweight to 1.4 5g daily per kg of bodyweight has shown increases in body fat loss, sparing of muscle mass, improvement in satiety, and improvement in blood sugar management without any change in total energy intake. Reducing your carbohydrate from a higher than necessary level can be a good strategy for fat loss but is incredibly hard without a high protein intake.
Increased glucagon. Protein consumption increases the amount of the hormone glucagon in the blood. Glucagon reduces the effects of insulin on adipose tissue (body fat), leading to greater fat loss.
Increased thermic effect of food. The thermic (the heating effect from eating food uses energy in itself) effect of protein is around double that of carbohydrates and fat. In actual fact eating protein can lead to a higher metabolic rate and greater loss in body fat.
If by now you are thinking what level of protein intake you should eat I am of course unable to tell you exactly the right amount for you personally but somewhere between 1.2 to 2.2g per kg in bodyweight daily will get you close to adaptation. I would place endurance athletes on the lower end of this scale and strength athletes toward the top with recreational trainers using weight training somewhere in the middle.
So when people tell you shouldn’t eat so much protein you have all the facts and you can smugly tell them;
“Its not my first rodeo…I got this!”
Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr. 2009.
A moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects. Journal of the American Dietetic Association, 2009.