Monday, August 23, 2021

Is too much protein bad for you?


A common fear I see people have when discussing nutrition is that eating too much protein is going to cause long term harm to their kidneys. Moreover, that eating too much red meat will cause type-2 diabetes, coronary heart disease and even cancer.


Before we address the fears, let’s quickly cover what protein does for us. Essentially, protein (or rather the amino acids that make it up) is the building blocks of the human body. From hormones to muscle mass it all comes from protein. And as you get older, the body becomes less sensitive to protein which leads to a condition called sarcopenia. Which is effectively age-related muscle mass loss. Effecting your overall ability to perform daily tasks such as walking around.


Being deficient in protein is out of the question.


The recommended daily intake of protein for a sedentary person sits around 0.8 – 1.2gs of protein per kg of bodyweight per day. This supposedly covers our basic needs and ensures the body is supplied with essential amino acids to assist with the general upkeep of all cells and muscles.


Should that person take part in regular physical activity then the requirement increases to anywhere up to 2.2gs of protein per kg. Sometimes even more. Depending on their age, weight and level of activity. If you’re putting your body through the ringer, you need to ensure it gets what it needs to repair itself. And what it needs is protein.


So, if it’s so important why all the fear?


Well believe it or not for a long time there was very little known about the potential negative effects of a high protein diet. Nutritional science is still a relatively new area. And even now, with all the methods of study we have available to us it’s incredibly difficult to run an effective study. It can be expensive and inconvenient to your subjects to run a closed experiment, and usually then you can only do it for a short amount of time. As such you must rely on humans self-reporting on their food intake at home, leaving the scientists to just draw conclusions from that data. Humans who are unreliable at the best of times who under-report or completely forget to report altogether.

As you can imagine poor conclusions have been made due to a poor data-pool. Observations are then made without considering additional lifestyle habits which more than likely also cause issues such as cancer and coronary heart disease.


More specifically, however, a 2018 study by Gang Jee Ko et al allegedly shows that high protein diets aggravate chronic kidney disease. This is quite often used to prove that eating too much protein can cause kidney disease. When it quite clearly states that the subjects already had CKD. And protein was aggravating this resulting in the need to reduce intake to improve quality of life.


This is what’s known as reverse causality. The subjects of the study already had the thing that the advocates were trying to prove was a cause of the thing. This is often seen in studies around artificial sweeteners and obesity. But that’s for another post.


For those who fear red-meat, I turn to my favourite study by Al-Shaar et al (2020) who compiled data from 50,000 men who took part in semi-regular food questionnaires from 1986 onwards. They were asked to record dietary preferences alongside other lifestyle habits. Interestingly, the conclusion was: “We found that greater intakes of total, unprocessed, and processed red meat were each associated with a higher risk of CHD. (Coronary Heard Disease)”.


Yet earlier in the study it was mentioned that:


“Those with higher total red meat consumption were more likely to smoke, consume alcohol, have diabetes, and use aspirin. They had higher intakes of total energy and trans fatty acids but were less physically active and less likely to have hypercholesterolemia or a family history of cardiovascular diseases. They had lower intakes of multivitamins, fruit, vegetables, and cereal fiber compared with those in the lower fifths of total red meat intake.”


This is a case of correlation not being equal to causation. Red meat was unlikely to be the sole cause of the CHD. More than likely it was the caloric surplus made up of processed meat alongside the smoking, drinking and all-around sedentary lifestyle.


Recent studies cited by NASM have in fact shown that we are not eating enough protein. And suggests that the recommended daily intake is up to 50% too low. (Bandegan, Courtney-Martin, Rafii, Pencharz, & Lemon, 2017; Elango, Humayun, Ball, & Pencharz, 2010; Kato, Suzuki, Bannai, & Moore, 2016; Pencharz, Elango, & Wolfe, 2016).


Research has also shown that those consuming upwards of 4.4gs per kg of bodyweight per day will not even see an increase of body fat mass over time when calories are controlled. (Antonio et al, 2015; Antonio et al., 2014; Claesson et al 2009).


All this is to say, don’t fear the protein. If anything, eat more of it. Especially if you’re currently in a weight loss phase. More protein, and especially more resistance training, will ensure you’re preserving that muscle mass.

Obviously, this isn’t to say you should be smashing burgers 4 times a day. Ensure your foods are as mixed as possible, unprocessed and including enough nutrients, greens, fats and carbs as well.


If you’re a vegetarian or vegan meeting protein targets can be a touch more challenging. Therefor supplementation is advised.


Also, as I’ve mentioned before, nutrition is prescriptive. These are general guidelines. Everyone is different. And everyone’s situation is different.


But also if you want the burger…. just have the burger.

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