Whenever I get a new client and they are a few days “in”, eating a healthy diet and experiencing what it feels like having a significant dose of protein with every meal, sooner or later I will get this question: “But isn’t eating so much protein bad?” I’m not sure where this fear stems from, but I blame the crappy fitness and health industry. No, it isn’t bad for you, quite the opposite is the case, it is healthy! Let me explain why.
The word protein comes from the Greek ‘proteios’, meaning ‘of first rank’, already indicating its importance. Proteins are responsible for most bodily functions and are found throughout the entire human body. They are your body’s worker bees. Over 40% of body protein is found in skeletal muscle, over 25% is found in body organs, and the rest resides mostly in the skin and blood. Check out Chantal’s article about protein for a quick reminder of what a protein is.
Functions of Protein
As already mentioned, proteins are of extremely high importance for your body, as almost every body function relies on them. A quick summary of the different roles of proteins:
- Structural elements: Several proteins have structural roles in the body. They are effectively part of the bricks, mortar and steel that is your body’s house. We are talking of muscles, connective tissue, skin, hairs and so on…
Muscle retention is higher with high protein diets – Houston et al. (2008). This is important especially for the elderly as it reduces fall risk!
- Catalysts (a.k.a. Enzymes): Enzymes are proteins that speed up chemical reactions and processes in the body. For example, in order to digest food you need enzymes. By the way, life would’nt be possible without enzymes, as the chemical reaction speed would be too slow.
- Messengers: Certain smaller proteins are hormones that act as messengers in the body to activate or deactivate processes, think of insulin for example.
- Buffers: Certain proteins act as buffers that regulate acidity levels of your blood and within cells. One prominent example is the hemoglobin found in red blood cells.
- Fluid balancers: Certain proteins, such as albumin, act as fluid balancers that regulate water levels, keeping water in your cells.
- Immuno-protectors and acute phase responders: Antibodies in your immune system that prevent you from getting seriously sick are proteins too; other proteins, called acute phase responders, regulate the inflammation response which is necessary for fighting pathogens and repair wounds.
“Protein deficiency compromises immune function, elevated levels may improve it” – Gjevestad et al. (2019)
- Transporters: Certain proteins act as transporters, akin to tiny ships in your body that have all kind of nutrients, water, hormones or drugs as their cargo.
- Other roles: Proteins carry out many additional roles in the body like cell adhesion and signal transmission in and out of the cells. In addition to their use in the synthesis of body proteins, amino acids are used to synthesize nitrogen-containing compounds that are not proteins but nonetheless play important roles in the body (like carnitine and creatine) as well as some of the neurotransmitters (for example phenilalanine is used to synthetize adrenaline and dopamine).
- Recovery from immobilisation: want to get healthy faster after being at the hospital? Perfect, eat more protein! Higher protein intakes have been shown to be beneficial after prolonged bed rest, post surgery and wound healing – Mitchell et al. (2017). But it should not wonder you after reading the whole list of what proteins do!
Generally speaking it is a good idea to err on the higher protein side for health as the following paper by Dr. Alexandra Johnstone (2017), aptly named “Why we shouldn’t ignore protein: Substantial evidence supports the increased consumption of high-quality protein to achieve optimal health outcomes”, calls for. Dr. Johnstone concludes: “Protein intakes well above the current Recommended Dietary Allowance help to promote healthy aging, appetite regulation and weight management”. What can you ask more?
Protein and weight management
Protein consistently is mentioned whenever we are talking about healthy body fat levels. And rightfully so:
- It increases satiety due to a decreased ghrelin secretion after a meal – Blom et al. (2006)
- It increases overall satiety, thermogenesis, sleeping metabolic rate and protein balance – Lejeun et al. (2006)
- It lowers spontaneous energy intake, which is especially important for non-trackers/ad libitum eating – Weigle et al. (2005)
- Greater weight loss, fat loss & muscle retention – Wycherley et al. (2012)
- Greater weight loss & improvements in HbA1C levels in type 2 diabetics – Dong et al. (2013)
- Greater weight loss, BMI, waist circumference, BP, fasting insulin & triglyceride reduction – Santesso et al. (2012)
- Significantly less fat free mass loss and more fat loss on higher protein intakes – Pasiakos et al. (2013)
As you can see, protein has a variety of mechanisms that make it useful in a weight loss scenario. It just makes dieting easier!
Next, let’s talk about a few terms regularly found in protein-related media:
Essential amino acids
Amino acids are the building blocks of every protein and there are nine of them that are essential for the human body. Essential in this context means that the body is unable to produce them on its own and is completely reliant on constant intake of those essential amino acids from the food.
In other words: your life depends on eating enough essential amino acids! Where do you find them? Well, pretty much all animal protein sources are complete and provide all amino acids that you possibly need. Vegans should try to eat a variety of different plant protein sources, at least over the course of a day, to make sure they cover all their needs. Plant protein sources usually lack one or more essential amino acids, but combining different sources evens things out.
As a strength trainee, you are interested in anabolism, the building process of your body. We want muscle tissue to grow and muscle consists mainly of protein, so we need sufficient protein intake.
Luckily protein intake is in itself a good signal for anabolism, so whenever we eat a meal that is rich in protein, we signal our body to grow, increasing protein synthesis acuetly.
How much protein should you eat to guarantee a good anabolic stimulus? Non-lifters should probably go for at least 1g protein per 1kg bodyweight, lifters and other athletes needs a little more, 1,5g and up are usually recommended. It also is a good idea to eat at least 20g of protein with every main meal as the body needs to cross a certain threshold to upregulate anabolism and these 20g per meal have been shown to be a good starting point.
So, why are people still afraid to eat “too much” protein? Well, because there are still plenty of protein myths out there:
In the following I want to explore some common myths about the “overconsumption” of protein. Somehow protein got a bad reputation and as soon as “normal people” see somebody with serious protein intake, they are worried if this is good for his/her health.
Again, I’m not sure where this fear comes from. Nobody freaks out if you stuff yourself with bread and pasta, but as soon as you eat a whole chicken breast, people think your end is near. So let’s see why everybody needs to calm down.
Veganism is all the rage now. The food industry happily jumps on this as they can now finally market cheap plant products with plenty of profit to high income custumers. Social media influencers and gurus preach the superiority of a vegan diet to gain exposure, followers and ultimately money. But animal protein sources really aren’t bad!
One of the main targets of vegan hate is dairy. But there is really good evidence that dairy is a great source of protein: “The totality of available scientific evidence supports that intake of milk and dairy products … may protect against the most prevalent chronic diseases …” – Thoring et al. (2016). Further dairy consumption is associated with lower:
- Insulin resistance, presence of atherogenic dyslipidemia and incidence of diabetes – Mozaffarian et al. (2010)
- Risk of developing a first myocardic infarction – Warensjo et al. (2009)
- Heart disease and stroke risk – Elwood et al. (2004)
- Risk of cardiovascular death – Bonthius et al. (2017)
- Inflammation – Bordoni et al. (2017)
Of course meat consumption, especially red meat, gets always gets a bad rep. I should probably write an entire article on this, but the main problem with all the red meat research is that we only have observational research. This is problematic as only correlation is found and no causation, but media likes to make no distinction between those very different findings. Red meat intake is often correlated with worse health outcomes because the population with high red meat intake is the same population with the lowest general health seeking behaviours. That means that these people are not concerned about their health, so they smoke, drink alcohol, go less often to the doctor, exercise less, have worse sleep hygene, etc., than a generally more health seeking population. You can try to correct for this with some statistics wizardry, but you can never make up for a huge systematic error like this.
Long story short: animal protein is perfectly save for human consumption. If you don’t like to eat it, it’s also fine, you don’t have to!
You often hear that a high protein intake causes dehydration. In genereal it is true that a high protein intake causes a higher water intake, however the overall inpact on hydration is only minimal. To back that up, we have research showing no signs of dehydration in men consuming 3,6g of protein per kg bodymass (that’s a lot!).
The dehydration myth seems to come from a study where dry rations for military personal were studied, showing a higher urine excretion with high protein rations. While this may prove useful in water restricted environments (like marshing through a desert), this isn’t of importance if you are able to drink as much water as you want.
Another popular protein myth is that protein is bad for your bones. The theory behind this belief states that sulfur-containing amino acids lead to acidification of the body and in order to neutralize this acidifying effect, calcium is removed from the bones. This is based on the observation that individuals on a high protein diet excrete more calcium in urine.
However, we now know that this acidifying effect isn’t detrimental to bone health, as your body is perfectly able to handle this on it’s own (as long as you follow some kind of healthy diet). The high calcium excretion can be easily explained by the effect that protein facilitates calcium uptake from your diet in the first place. Therefore your body has to get rid of the increased calcium in your body again, increasing calcium excretion.
Liver and Kidney Toxicity
Thirty years ago a scientist established an hypothesis that increased glomerular filtration rate (GFR) due to increased protein intake can lead to liver and kidney damage. GFR is a measure of how fast your kidney can eliminate waste products and the theory stated that a high GFR leads to higher pressure inside the organ, increasing the risk of damaging it.
Nowadays we have research showing that no organ damage is caused by high protein diets, even with very high protein intake (over 2,5g per kg bodyweight) over an entire year. Most experts agree that the higher GFR is just an adaptation of the body and is entirely physiological (not harmful in any way). GFR also increases during pregnancy, and as we know, being pregnant is not unhealthy in any regard.
There’s nothing inherently wrong or unhealthy about consuming more protein than your body can use to build muscle. The excess will simply be used as energy. Even highly excessive protein intakes consumed for months on end generally do not affect your health negatively and that includes your kidney health.
Proteins have a wide array of functions in your body and we need to consume them regulary to prevent catabolism, the state where your body “eats up” its own muscle or even organ mass to sustain its need for protein. This is even more important if you are in a calorie deficit! Live a healthy lifestyle, drink plenty of water, eat a balanced diet and enjoy your steak as often as you like 😉 .
Do you know of any other protein myths? Please let me know, comment down in the comment section!