Nutrition Science Articles
Why & How to High Protein Diet
Protein is the macronutrient in vogue at the minute, with Supermarket shelves full of ‘high protein’ this and ‘good source of protein’ that. Every other magazine seems to be promoting a high protein diet, but what does this actually mean?
Is it a good idea, and if so – how do you implement it?
Any besides - what the hell is protein anyway? We’ll start with this one.
What is Protein?
Protein is a term used for a category of compounds found within organic material, with the most abundant dietary sources being animal products like meat, fish, eggs and dairy, (though a not-too-insignificant amount can also be found in some plant sources).
It’s made up of long chains of molecules known as amino acids, which are the vital “building blocks for life” for every organism on the planet. When you eat a food containing protein, your body breaks it down during the digestive process into these amino acids which it can then use to make new proteins for use in muscle cells, hormones, hair, skin, nails and bone. Think of it like getting a bunch of Lego models, breaking them up into individual blocks and then rebuilding them into something else.
Protein has a load of different benefits to it (aside from what should now be obvious, namely that it’s vital to ‘make’ just about every part of you, including hair, skin, hormones, digestive enzymes and antibodies which fight disease). First, consuming protein is the main way in which we can activate a process known as ‘muscle protein synthesis’, which is essentially your body depositing protein into muscle fibres. Activate Muscle Protein Synthesis and you are building muscle tissue, do this over time in combination with a calorie surplus and weight training?
And even if you are looking to lose fat rather than build muscle tissue right now, protein has benefits. Protein Synthesis is a way in which your body protects and preserves muscle tissue, not just builds it, which means that eating enough protein is vital for dieters who don’t wish to end up looking like they are auditioning for The Machinist 2 (1). It is also highly satiating, more so than any other macronutrient, which means that it makes dieting far easier (1).
All of this is great, and it sounds like a high protein diet is the way to go, right? Well – that very much depends on what you consider to be a ‘high protein diet’, because this is far from a specific term.
The government recommend that women have 55g and men 65g of protein per day (2). That’s around 275 and 350g of chicken breast per day respectively, though realistically because of the tag along proteins in grains, beans and even vegetables, most people will meet this without trying if they eat a stereotypically ‘healthy’ diet.
This amount will theoretically be enough for a sedentary person aged below 65 (ish) to maintain normal metabolic function and produce all the hormones and hair that they want/need – with older people needing slightly more due to an impaired ability to use protein to do stuff. When it comes to getting the rest of the benefits of protein within a diet, however, you need a little more – and this is where the waters get murky.
Ask 3 different people what a high protein diet is and you’ll get three different answers, because there’s been a great number of different variations on the same theme over the years. To some, a high protein diet means that you eat a lot of meat and little else, to some a high protein diet means you have 40% of your daily calorie intake from protein, and to some a high protein diet means you multiply your bodyweight in kilos by 4 and eat that many grams. Opinions vary, but the literature is relatively constant.
According to the majority of the literature, a healthy, young and active person who partakes in some form of resistance training on a regular basis should be having around 2-3g of protein per kilogram of bodyweight depending on goals and body composition (3-4). This may or may not be a ‘high protein diet’ depending on who you ask, but it will be a diet which provides adequate protein for any needs, and realistically THAT is what we should be thinking about.
Do you go for 2 or 3, or somewhere in the middle? That depends. Generally speaking you’d go higher if you’re lean and dieting, and lower if you’re ‘softer’ and/or not looking to lose fat right now. Your intake should be dictated by where you lie on that spectrum, but please note that going a little higher than you need won’t cause harm directly (5).
No, in fact there is no research to date which shows that an excessively high protein intake causes any harm. That’s not to say that it definitely doesn’t – if you take your intake to ridiculously high levels there is no data, but hypothetically it should be absolutely fine within the levels we’ve highlighted here. Generally if you eat more protein than is needed we end up with a surplus of the above mentioned amino acids, and they just get sent to the liver to be converted into glucose and used as energy. Your steak just becomes expensive carbs – no harm, no foul.
The only time when a high protein intake would realistically cause an issue is if it was to lead to an imbalanced diet. This could be a lack of carbohydrates or fats, or indeed of fibre and micronutrients if an excessively high protein intake was limiting the intake of these other foods in some way (either driven by appetite or by caloric balancing). Eating so much protein that you can’t eat enough calories because you’re too full, or eating so much protein that your gym performance sucks due to a lack of carbs isn’t a good idea.
Aside from that, we need to consider that my flippant remark about ‘expensive carbs’ has an element of truth to it – protein based foods aren’t cheap and this could impact your food bill quite a bit. If your protein intake is so high that it is impacting you financially, it could cause undue stress on you or your loved ones and, of course, make your overall approach a LOT harder to stick to long-term. Adherence is key and if protein so filling that you can’t eat enough food, or if you can’t afford to run your car because you NEEDED another g of protein per kg then you have no chance of staying on course as long as you need to.
Finally, if one doesn’t account for calories and simply eats a bunch of protein, then you’re going to get fat eventually because you’ll be consuming too much food.
So is a high protein diet needed? Well, that depends on what you consider a high protein diet. A good intake of 2-3g per kilo can be hugely beneficial, though, and this is what I recommend.
- Stuart Phillips. A Brief Review of Higher Dietary Protein Diets in Weight Loss: A Focus on Athletes. Sports Med. 2014; 44(Suppl 2): 149–153.
- Food.gov Nutrient Institution (PDF)
- ACSM Position Stand. Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise: March 2016 - Volume 48 - Issue 3 - p 543–568
- Helms et al. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr. 2014 May 12;11:20. doi: 10.1186/1550-2783-11-20. eCollection 2014
- Tipton KD. Efficacy and consequences of very-high-protein diets for athletes and exercisers. Proc Nutr Soc. 2011 May;70(2):205-14. doi: 10.1017/S0029665111000024. Epub 2011 Mar 7