The Anabolic Agent - Leucine

When it comes to marketing, you can’t go wrong throwing in ‘anabolic’. It suggests all the things we all want be – muscular, strong and powerful. The anabolic window is a term that is often used to describe the first hour, post workout, but recent research suggests that we have multiple anabolic windows throughout the day and understanding them could be the key to protein intake, meal frequency and optimising your own muscle development.

Current recommendations are that daily protein intake is the most important factor and that as long as you hit your requirements, the frequency and timing doesn’t matter quite as much. Couple this with some suggesting a protein intake of 4g/kg bw, others suggesting 0.8g/kg bw and you have a room for interpretation. A lot of room for interpretation!

Leucine has been established as the key amino acid when it comes to muscle protein synthesis, and, mps is our anabolic response. Research has shown that a dose of 3-4g of leucine will maximise the post feeding anabolic response but since leucine content in food varies and leucine supplements are expensive it is crucial to understand that protein choice will determine the anabolic affect of a meal.

Oh, and before you go mega dosing, it would appear that the anabolic response does have a ceiling, so the more the better just doesn’t work in this case.

So how much?

Firstly you need to determine your leucine needs (0.05xkg/bw) this will give you the amount of leucine you need to maximise your anabolic window. You could also just go off 3g and you would probably be ok. Secondly, you need to look at the different leucine content of foods, as this will determine the amount of the protein source you will need. For example whey protein is 11% leucine whilst soy protein is 7%.

So for a 95kg guy: 0.05x95 = 4.75g of leucine per meal Whey protein is 11% leucine content = 4.75 x 11

= 52g of whey protein

How often?

It appears that although mps returns to baseline after 2-3 hours, leucine plasma levels remain elevated for 4-6 hours. During this time it would appear unlikely that you can re-stimulate mps until these levels also return to baseline. However there is evidence that consuming some carbohydrates and free form EAA’s in between complete protein meals enhanced mps when compared to those who did not supplement between meals.

So what does this all mean? It means eating larger meals, further apart. The meals would vary dependant upon the leucine content of the meal.

I would suggest eating 4-5 meals, roughly 5 hours apart. Getting a minimum of 3g of leuince per meal to stimulate the anabolic response. You could also try consuming 20-30g carbs and 15g free-form EAA’s inbetween meals to maximise the response if you really are looking for that extra edge in packing on those lean pounds

 

Protein Source

% of leucine from total amount

Amount of protein needed from source to reach   3-4g leucine

Amount of food source needed to reach 3-4g   leucine

Whey Protein Isolate

12.0%

25-33g

27-36g

Milk Protein Isolate

9.8%

31-41g

34-46g

Casein

9.3%

32-43g

Varies upon brand

Egg

8.6%

35-47g

Approx 4.5-6.5 large whole eggs

Fish

8.1%

38-50g

158-208g

Beef

8.0%

38-51g

126-170g

Chicken

8.0%

38-51g

133-179g

Pork

7.5%

41-54g

132-174g

Wheat

6.8%

44-59g

15-20 slices of bread

 

Taken from Optimal Protein Intake And Meal Frequency To Support Maximal Protein Synthesis and Muscle Mass by Dr. L. Norton.

By Dan Forbes

Acknowledgements

Dr L. Norton Padden Jones et al J. Bohe, J.F Lowe et al

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