These days it is ALLLLLLLLL about protein. Since the days of Dr Atkins and his infamous low-carb diet and the emergence of ‘middle class’ higher income families, it seems we have all been on the protein bandwagon. And I get it…..protein is important. Protein gives us more satiety than carbs or fats (keeps us fuller for longer), is an essential component of our muscles, our skin & connective tissue such as collagen. Protein also forms regulatory enzymes in the body that catalyze the breakdown of compounds such as lactate and alcohol, and damn straight we need it to rebuild and repair muscles after they have had a big workout.
But how much do we need?
Well according to current recommendations we are all eating way too much of the stuff. The RDI of protein for a male aged 19-70 years is 64 grams and for a female aged 19-70 years is 46 grams (Stewart, 2011). Or if you want to work it out specifically for your weight, men and women both need less than 1 gram of protein for every kg of their own body weight per day (ie. I weigh 56 kgs, so I need < 56 grams protein per day).
Now keep in mind that unless you are an elite athlete or you have a special condition requiring higher a protein intake (such as Anorexia Nervosa, Burns, Ageing) these are pretty standard figures. Elite athletes are recommended up to 1.4 g protein per day/per kg of body weight and strength trained athletes up to 1.7 g of protein per day/per kg body weight (Burke & Deakin, 2005). For example, an AFL player weighing 90kgs might be consuming around 126 grams of protein per day. Yet many of us normal beings are eating just as much as this!
Let’s have a look at the content of some food sources of protein:
Lean Chicken Breast – 28g
Hard boiled egg – 12 g
Snapper fillet – 27 g
Cheese, cheddar (100g) – 25 g
Lentils (100g) – 7g
Now this is just wholefoods, I haven’t included protein supplement products like powders, bars etc etc. Typically protein powders have around 17-25g of protein per serving.
So if you’re having a chicken boob, some cheese, an egg and a protein shake, you are consuming around 92 grams of protein in one day (consider this with regards to those RDI figures above). And this isn’t even factoring in the protein from everything else you might be eating in that period! There is protein in those oats or slices of toast you are having for breakfast, that coffee you’re drinking, that mid afternoon yoghurt, the tuna/beef/tofu/quinoa in your lunchtime salad.
It is easy to see that most of us are probably eating a diet that far exceeds the recommended amount of protein. Question is, does it matter?
You see, our bodies only use the amount of protein they require and we essentially just pee out the protein that we don’t use (what a waste of money hey, all that protein powder?). The kidneys are the little guys responsible for metabolising protein, and it makes me wonder how they’re coping with it all. Surely large amounts of dietary protein would be placing additional stress on our kidneys? Will we see more renal disease in the future, in us, this generation of high protein peeps?
I am not sure we actually know the answer, as diets that are so high in protein are a relatively recent phenomenon. From a clinical studies perspective, we seem to know alot more about what effect high carbohydrate diets have on our bodies than high protein diets.
With such a critical role in the body, it is not surprising that protein metabolism is complex and still incompletely understood. What we do know is the body uses the precise amount of protein that it requires, and no more. Eating additional protein on top of what your body needs is going to offer very little benefit, as the excess will just be excreted in your wee. It has been hypothesised that high levels of dietary protein could lead to kidney disease, via a mechanism called Glomerular Hyperfiltration (which basically just means the kidneys are working overtime to ‘filter’ the blood), as well as Nephrolithiasis (the development of kidney stones). The jury is out, many of the studies I have read suggest that this is not the case, however these have largely been carried out with small sample sizes and over relatively short periods. Further research needs to be done into the longer term effects of prolonged high dietary protein intake on kidney function.
If you have any kind of kidney-related condition, it is important you consult a GP or Dietitian before considering a high protein diet.
Have a great week folky folks!