The smart way to maximise protein synthesis

Not all proteins are created equal so eating the right types at the right times is the best way to improve muscle protein synthesis, says Layne Norton

Dr Layne Norton is a physique coach and natural pro bodybuilder and powerlifter, who holds a PhD in Nutritional Sciences. He is based in Tampa, Florida.

went into my PhD hoping to find data so I could increase the amount of protein I ate per day. Instead the opposite happened. I went from a target of 1.5g of protein per pound of bodyweight to 1g, because there was no evidence that taking more than that amount had any additional muscle-building effects. And here’s why.

To increase muscle protein synthesis the most important macronutrient is obviously protein.

But not all proteins are created equal. It appears that the leucine content is the dominant factor in increasing muscle protein synthesis. Our lab showed that about 60% to 70% of the anabolic effect was down to leucine and there’s a leucine threshold you need to hit per meal to get this response.

Bodyweight and lean mass are clearly significant factors in how much you personally need, but in general terms the minimum dose seems to be about 1.8g to 2g of leucine per meal is needed to initiate the response.  The effect is maxed out at about 2.5g to 3g: after that there is no additional beneficial response.

Minimum effective dose
Different protein sources have different leucine contents, so for whey, eggs or animal sources, you may only need around 30g to hit this leucine target, whereas for a soy or wheat or plant protein – which have a lower leucine content – you may need up to 40g. So you can maximise the anabolic response with less-quality protein sources, you just need to consume more of it.

Also, you can’t make up for a long period of low protein consumption by having a very high amount of protein later in the day. This makes sense when you consider you need to hit that leucine target to initiate the anabolic response. If you’re eating 100g of protein at one meal, you’re not going to get a bigger response than eating around 30g.

Carbs and fats
In adults, insulin isn’t anabolic, so eating a bunch of carbs post-workout won’t increase muscle protein synthesis. For that you need protein. Protein plus carbs does seem to increase the response slightly, but you only need a very modest amount – around 20g to 30g of carbs – to achieve the desired effect.

There’s not a whole amount of data on fats just yet and I can’t say one way or the other but it seems fat has a fairly passive role in muscle protein synthesis. It might depend on the fatty acids: some might have a positive role, while others might have a negative impact. It’s too early to know.

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