Last week I wrote about the timing of workout nutrition, concluding that pre-workout nutrition is vital to athletic performance and improvements to this performance. However, there’s also debate on the content of the nutrition.
I’ve set out below various parts of the debate so that you can reach your own conclusions.
Pre workout nutrition
A small study by Hackney et al (2009) comparing the effects of protein and carbohydrate pre workout nutrition for trained individuals carrying out resistance training. This showed that the protein group had a more significant increase to their resting energy expenditure.
The conclusion by the researchers was that having a protein supplement prior to weight training could be a simple and effective way to increase energy expenditure. Therefore if you are training to improve your body composition then getting protein into your pre workout nutrition seems to be important. Unfortunately this study seems to clearly divide protein and carbohydrate and doesn’t comment on having a mix of the two together pre workout.
Do we even need carbohydrate for our workout nutrition?
Having become quite open minded about workout nutrition after writing last week’s article, I was unsurprised to discover DiPasqual’s idea that ingesting carbohydrates straight after our workouts to “replenish the glucose stores in the muscles” is a myth.
In an article on Bodybuilding.com he summarises his argument that while exercise increases insulin sensitivity and depletes glycogen, the body increases glycogen in the body (both muscle and hypatic (liver) glycogen) as a priority after exercise.
As soon as the body increases the glycogen in the body substantially, our insulin sensitivity drops again. However, it is advantageous to keep insulin sensitivity high for as long as possible after the workout since increased insulin sensitivity:
- enhances amino acid uptake;
- enhances protein synthesis;
- increases profusion of muscles so gets more nutrition into muscles and enhanced anabolic effects from protein synthesis; and
- alerts the body to use fatty acids as the primary fuel after exercise.
Loading up on carbohydrate straight after the workout rapidly decreases insulin sensitivity so that the fatty acid burning, enhanced protein synthesis benefits of the heightened insulin sensitivity stop.
Think twice before having a potato post workout
This idea is supported by a study carried out by Garcia-Roves et al (2003) which concluded that preventing the supercompensation of glycogen after exercising results in the persistence of exercise-induced increases in protein synthesis. However, it should be noted that this study was carried out on rats (who were exercised through swimming), not resistance training humans.
Newsom et al (2009) have also noted that a carbohydrate deficit after exercising contributes to the insulin sensitising effects of exercise, though again there is an issue with relying on this study – it relates to acute aerobic exercise, not resistance training.
Protein: the alternative to post workout carbohydrate
It is clear from a study carried out by Koopman et al (2004) that protein is needed in post workout nutrition in order to stimulate muscle protein synthesis and optimise protein balance (when compared to carbohydrate only post workout nutrition).
A study carried out by Børsheim et al (2002) looked at the stimulation of net muscle protein balance when 6g of amino acids (an active part of protein) was administered 1 and 2 hours after resistance exercise. Interestingly this showed that the protein synthesis benefits from the amino acids administered after 2 hours were even greater than those from the first dose. So perhaps the best thing you can do after your post workout protein shake is to have some more an hour later.
Choice of protein source
It seems that, whatever you believe, we must have protein after our workout and indeed, most of us are programmed to drink down a whey protein shake or a pint of milk as soona s we get out of the gym for our post workout protein source.
But there are a few things to be aware of with dairy proteins:
- Whey protein undergoes a gluconeogenic response and gets into our system very quickly so that a lot of it gets converted into glucose and hits insulin sensitivity levels. A study carried out on diabetics using whey protein with their meals reflected the higher insulin responses they had to these supplemented meals.
- All proteins release insulin but Robb Wolf mentions in the Paleolithic Solution Episode 9 (about 28 mins in) that dairy proteins produce much higher levels of insulin.
So if you are trying to keep your insulin sensitivity elevated for as long as possible after a workout it may be beneficial to avoid dairy proteins as well as carbohydrates post workout. That leaves things like lean steak and fish as optimal post workout “snacks”.
Sardines post workout?
Summary
From the research I’ve done it seems that while protein in pre workout nutrition seems to be a given, the choice of post workout nutrition depends on your goals.
If body composition is a priority (eg figure athletes) then consider avoiding significant levels of carbohydrate and dairy in post workout meals. This optimises the enhanced protein synthesis and fatty-acid-burning triggers caused by the increased insulin sensitivity.
If maximising the glycogen in muscles is more important (eg. powerlifter training on a very frequent basis) and body composition is not a priority then maybe continue to load up on carbohydrates as part of the post workout nutrition. Just don’t neglect the protein.
I’d love to hear from you if you’ve seen other research that disagrees with this information – workout nutrition seems to be a minefield of contradictory studies!
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