How much PROTEIN should YOU be eating?

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High protein intakes directly contribute to muscle growth during weight gain and muscle retention during weight loss.

Reading time: ~5 minutes

Physiology 101:

Protein is composed of amino acids, which are the building blocks of the contractile proteins in muscle. Simply put, if you want to build muscle at the best possible rates, you will need to supply your body with protein for the two following reasons:

  1. so that your body can use the protein you’re eating to further build muscle mass. The process of creating (synthesising) new contractile proteins in muscle is called Muscle Protein Synthesis (MPS).
  2. so that your body does not need to get its amino acids directly from your muscle – thereby breaking down your hard-earned muscle mass. The process of breaking down your muscle’s contractile proteins is called Muscle Protein Breakdown (MPB) – you want to avoid this!

The net balance between these two is called the Net Protein Balance.

Net Protein Balance = MPS – MPB

Building muscle requires both energy and the necessary building blocks. The building blocks are the amino acids contained in protein. The energy required to build muscle can be obtained in several different ways, but, in order to ensure you’re building (and minimising breakdown of) as much muscle as you can, you should be eating more calories than you’re burning.

Why? Well, if your body needs energy to build something, and it’s not getting that energy from the diet.. it’ll breakdown some of its structures to get energy from them. In some cases, that might be muscle mass – which means you’ll lose muscle.

It could also take that energy from your body’s fat or carbohydrate stores.. in which case you won’t be able to perform maximally well! And if you can’t perform optimally, you’re also not providing your muscle with the best possible stimulus.

On the contrary, if plenty of energy is available via your diet, your body won’t have to resort to breaking down some of its structures to get energy to build or maintain some other stuff. Namely, if you’re eating more calories than you’re burning, the energy necessary to build muscle will be readily available and your body will be much less likely to breakdown your muscle/other substrates (like carbohydrate/fat stores) for energy.

The same rationale goes for amino acids/protein. If your body needs amino acids to build stuff, but your diet doesn’t have a sufficient amount of them, it will need to breakdown some of your structures to get the building blocks – meaning you might lose muscle mass.

On the other hand, again – if you have a sufficiently high and constant supply of amino acids in your diet via adequately timed and portioned protein intake, your body won’t need to break down its structures, meaning you can both maximise Muscle Protein Synthesis and minimise Muscle Protein Breakdown, resulting in the best possible muscle growth.

That ends Physiology 101.

Now, what really interests us is; if protein is so beneficial to us, how much of it do we need?

No research supports a protein intake of more than 1.8g/kg/day of high quality protein. Most research actually doesn’t find a benefit in how much muscle you gain/retain above a protein intake of 1.6 g/kg. If you’re eating 1.8g/kg of high quality protein daily, then it is very unlikely (though possible) that you’ll benefit from eating more than that.

Keep in mind that response can be vastly different between individuals. Depending on how muscular someone is, their genetics and many other factors, some people may need LESS than 1.8g/kg, while others might need MORE. With that being said, it’s pretty hard to actually objectively tell (especially using available methods) whether or not you need more protein, especially as an athlete. It’s not like you can just “feel” your body needing protein, or see a night and day difference between eating 1.5 vs 1.55g/kg. If you want to play it extra safe, eat a little more than 1.8g/kg daily.

There are some situations, however, where increasing/decreasing your protein intake is appropriate and beneficial.

When should you increase protein intake?

  • If you’re hungry and trying to lose weight

When you’re losing weight, increasing protein intake might prove useful. Protein is pretty satiating – just try eating 2 kilograms of chicken breast for example. That comes out to 2000 kcal or so – but you couldn’t eat all of it at once. Now, if you were to eat 2000 kcal worth of pizza.. that’s a different story. You would easily be able to eat more.

Some research also suggests higher protein intakes help with mood when dieting. No research (to my knowledge) has shown better body composition changes (how much muscle you’re retaining) in protein intakes >1.8g/kg though, so the physiological benefits of eating more protein might stop at ~1.8g/kg when losing weight.

ADDENDUM 02/12/2018:

I might have been mistaken about this. Anecdotally, I still think protein, on a calorie per calorie basis often makes people satiated more quickly than fats (pretty much always) and carbs (most of the time). An exception might be some foods like vegetables, whose volume to calorie ratio is very high and hence quite satiating.

  • If you’re plant-based/vegetarian/vegan

Plant-based sources of protein are usually inferior to animal protein (on a gram per gram basis) for 2 distinct reasons:

  1. Plant protein is digested less easily
  2. Plant protein usually has less leucine than animal sources of protein (and generally is more prone to having an imbalanced amino acid profile)

Because of these two reasons, it’s a pretty good idea to increase your protein intake above 1.8g/kg when avoiding the consumption of animals/animal products. How much should you eat instead?

Well, it depends on how much leucine the foods you consume have. If you’re vegetarian and consume primarily high quality protein from sources like whey, your requirements probably don’t change that much. To be on the safe end of things, consider eating a little more protein.

As a rule of thumb, 2.1g/kg of protein a day seems to be a good recommendation for vegans. If you avoid foods containing soy, however, and choose to base yourself on primarily grains and legumes, your requirements might be higher.

  • If you’re elderly

In studies, elderly subjects benefit from consuming a bit more protein than young subjects. This is because they are less responsive to the anabolic effects of essential amino acids in particular, and hence necessitate bigger protein servings to maximise Muscle Protein Synthesis. I’m no expert on the topic, but it would seem that elderly trainees are less responsive to Leucine – the amino acid that signals a spike in Protein Synthesis – which means they need more total protein per serving, particularly Leucine. So, you can either increase total protein intake or simply aim to consume foods with more Leucine to make up for your reduced sensitivity.

When should you decrease protein intake?

  • If you’re eating a ton of protein already

If you’re eating MUCH more than 1.8g/kg of protein a day, you might actually be limiting your results a little. Simply put, while protein is really good at providing you with the building blocks for muscle, it is not the best source of fuel for weight training/high intensity exercise. Hint: fats also aren’t the best energy source/substrate.

Yep, eating more carbohydrates – especially if you’re not eating many – can aid performance a bit. Since decreasing protein (down to ~1.8g/kg) won’t reduce muscle gain, but increasing carb intake will improve performance (and stimuli for muscle growth), it might be worth considering switching some of your protein with additional carbohydrate intake.

  • If you have trouble eating enough calories

Protein is satiating. On a calorie per calorie basis, protein is more satiating than both fat AND carbohydrate (despite the fact that fat has over twice has many calories).

Because of this, IF you’re struggling to consume sufficient calories – but are already consuming over 1.8g/kg when maintaining/gaining weight or perhaps a little more when losing weight – you might want to consider replacing some of that protein (down to 1.8)  by carbohydrate/fat. As discussed above, carbohydrate is usually a better fuel for training than fat – as such, eating more carbohydrate (especially in a liquid form, which is notoriously easy to consume in large quantities) is a GREAT idea if you’re struggling with caloric intake. Bear in mind, though, that getting enough calories in is priority number 1 here, and whether those calories stem from fat or carbohydrate is only a relatively small detail – so, if you just LOVE high fat foods, and struggle to eat enough calories using carbs, knock yourself out.

ADDENDUM 02/12/2018:

I might have been mistaken about this. Anecdotally, I still think protein, on a calorie per calorie basis often makes people satiated more quickly than fats (pretty much always) and carbs (most of the time). An exception might be some foods like vegetables, whose volume to calorie ratio is very high and hence quite satiating.

Key takeaways;

  • If you eat meat regularly, you won’t put on additional muscle mass/retain more muscle mass past eating 1.84g/kg of protein a day.
  • If you’re plant-based, vegetarian/vegan, your requirements increase.
  • Under certain circumstances, it’s worth considering a higher/lower protein intake – such as when losing weight or if you’re elderly.

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