There has been a lot of attention on the idea of nutrient timing over the past decade or so and how it might be able to offer ergogenic benefits over that of the actual supplements themselves. Opinions and research itself has varied from stoic support of the ‘window of opportunity’ to a casual ambivalence towards the idea. As research is always evolving, so should your ideas and methods. This article looks at some of the latest research and reviews regarding supplementation so you can be more informed to make the best choice for you.
Defining Nutrient Timing
When discussing or debating any topic, it’s important to provide the necessary definitions so that we have a reference point to address our arguments against and to keep our opinions on track. A broad but encompassing definition of nutrient timing is ‘a nutritional strategy in which precise amounts of particular nutrients are delivered at precise time points, relative to exercise, in order to enhance performance or training effects.’
As there have been countless studies in relation to nutrient timing and its effects, this article will focus more on nutrient timing in relation to oral supplementation and their effect on muscular adaptations with a bout of resistance training.
The Overall Importance of Nutrient Timing
While your overall diet is of course the key to achieving long term success in strength training and bodybuilding; with supplementation, consuming those at the right times can mean the difference between looking first rate and second best (taking aside other factors such as genetics, etc). Take the commonly quoted study of Cribbs and Hayes (2006)1 for example in which he supplemented two groups of recreationally trained males with a carbohydrate, protein and creatine supplement either in the morning and evening (MOR-EVE) versus supplementing with the same supplement pre- and post- training (PRE-POST). After 10 weeks of resistance training, they were able to show better body composition, strength gains and increased type 2 muscular fibres with the PRE-POST group than the MOR-EVE group. It makes sense that nutrient timing should be based around the times where your muscles are maximally stimulated in terms of protein synthesis; the resistance training session. Again, to reiterate, this is not to say that one cannot make any gains by consuming supplements any time of the day with resistance training. It merely means that to get the most out of your supplementation and training, there’s a substantial collection of evidence showing positive effects of supplementation within the period close to resistance training times. There are 3 such periods overall in which studies are based around; pre-training, intra-training and post-training.
A majority of studies looking at pre-training supplementation have focused on endurance based aerobic activities such as cycling, running, etc. However there is growing interest in possible muscular adaptations with pre-resistance training supplementation, however research is still in its infancy and equivocal. Take for example Tipton et al (2001)2 where he showed in a small sample of subjects that consumption of an essential amino acid (EAA) and carbohydrate supplement immediately prior to a resistance exercise session resulted in greater amino acid delivery and muscle protein synthesis than post-consumption. Contrast this to Tipton et al’s (2007)3 later study in which he showed that 20g of whey protein consumed pre- or post- resistance training did not result in significant differences in amino acid delivery and net muscle protein balance between the two groups. Furthermore, Fujita et al (2009)4 showed that 2hr post-exercise muscle protein synthesis rates did not differ between subjects who consumed an EAA and carbohydrate supplement pre training and those who simply fasted. Still other studies such as White et al (2008)5 were able to show a slight, but non significant trend in favour of carbohydrate and protein supplementation for attenuation of strength performance. Many studies and reviews however look at pre- and post-exercise supplementation which makes it hard to separate the results to find the significance of the pre-exercise supplementation by itself. Furthermore, few studies differentiate between carbohydrate or protein supplementation independently before exercise for ergogenic benefits.
Recommendations for Pre-Exercise Supplementation:
- If performing extended resistance training sessions (>90 mins) or more endurance based, high intensity sessions (>60 mins), consumption of carbohydrates before resistance training at 35g or 0.5g/kg of fat free mass may be beneficial in promoting muscular adaptations and alleviating strength losses.
- Consumption of protein before resistance training with at least 6g of essential amino acids or 20g-30g of whey may help to promote further muscle mass gains and beneficial adaptations.
- It is definitely wise to consume both protein and carbohydrates in conjunction, however, protein ingestion alone can elicit muscular adaptations.
- Supplementing with carbohydrates becomes more relevant when also supplementing with creatine.
As with pre-workout supplementation, studies looking at nutrient intake during the training period has often focused on endurance based activities. A more elegant study by Bird et al (2006)6 took 32 untrained male subjects and split them into four groups; a group consuming only a carbohydrate supplement during a resistance training session (CHO), a group consuming only an essential amino acid supplement (EAA), a combination (CHO+EAA) and a placebo group (PLA). Bird et al were able to find that those consuming just CHO were able to significantly attenuate cortisol rises with concurrent rises in insulin. The combination CHO+EAA group were further improve these results. In terms of muscle damage markers, while both CHO and EAA alone were able to reduce muscular damage compared to the placebo group, the reduction was not significant compared to pre-exercise values. However, the combination group has a statistically significant reduction in muscle degradation. In subsequent studies, Bird et al were able to show that similar results occurred with either a single bout7 of exercise or over 12 weeks8 of resistance training. Furthermore, over 12 weeks of resistance training, while all groups were able to increase muscle fibre cross sectional area (size), the most pronounced increase was from the combination group, with similar smaller increases in both the CHO and EAA alone groups. As with many nutrient timing studies, most studies look at more than one period of supplement ingestion time, ie before and during, during and after, which makes it hard to differentiate and isolate benefits from specific nutrient timing points.
Recommendations for Intra Training Supplementation:
- Consumption of protein and carbohydrates independently during a resistance training session may be able to attenuate cortisol rises, increase insulin levels, reduce muscular damage and improve muscle fibre size.
- Consumption of protein AND carbohydrates together can further potentiate these results.
- At least 6g of essential amino acids in a 6% CHO solution is recommended during a resistance training session.
- Additional branched chain amino acids (BCAA’s) may be included as higher intensity resistance workouts increase BCAA catabolism. Studies examining their use during resistance exercise are sparse.
A majority of the studies examining supplementation and resistance exercise have utilised post-resistance exercise supplementation. The main reason being that this is considered as the time in which the muscle is maximally stimulated in terms of protein synthesis. There is plenty of evidence that post resistance training supplementation works, however the actual timing of this supplementation has had fewer studies. Those that have looked at post-exercise supplementation timing have often compared between pre and post supplementation and different time periods of post training supplementation. Reiterating Tipton et al’s (2007)3 study showing no difference between 20g of whey consumed either before or after training on muscular adaptations and Tipton et al’s (2001)2 earlier study showing a lesser effect when EAA’s and CHO were consumed post exercise and comparing these studies to Rasmussen et al’s (2000)9 study showing no difference with protein and carbohydrate supplementation either 1hr or 3 hrs post workout, it is hard to find a discernible time for after exercise supplementation. It is interesting to note however that immediate consumption of an essential amino acid and carbohydrate supplement was less effective than when consumed 1hr post resistance exercise. Perhaps, the timing becomes more relevant with age as studied by Esmarck et al (2001)10 in which he found that muscular hypertrophy and muscle fibre adaptations were improved to a larger extent in elderly retirement age males who consumed a nutritional supplement providing 10g protein, 7g of carbohydrates and 3g of fat immediately post resistance exercise over those who consumed it 2hrs post training over a 12 week trial. This idea however is debated by both Candow et al (2006)11 and Verdijk et al (2009)12. In terms of post resistance training supplementation and attenuation of strength losses and markers of muscle damage, Cockburn et al (2010)13 were unable to show differences between those who consumed a protein, carbohydrate and fat supplement either immediately after training or 24hrs post training.
Recommendations for Post Training Supplementation:
- Ingestion of carbohydrates after resistance training is beneficial and can promote protein synthesis, but perhaps not enough to create a positive net protein balance.
- Ingestion of carbohydrates may also help promote glycogen resynthesis in highly intense workouts or workouts over 60-90 minutes.
- Combining both carbohydrates (30-40g high glycaemic index) and protein (6-20g of EAAs or 20-30g of whey) is the most ideal method of post-exercise supplementation for muscular adaptations.
- There is currently no evidence in young, healthy, trained populations that the timing of supplementation post exercise anytime within 3 hrs makes a significant difference in muscular adaptations.
- However, if essential amino acids are the sole source of supplementation, consumption at 1 hr is perhaps better than immediate consumption.
- Timing of supplementation is perhaps more important in elderly subjects, with an inclination towards more immediate supplementation post training.
- Combining creatine (5-10g) with protein and carbohydrates has also been shown to further augment muscular adaptations over single nutrient supplementation alone and even when compared to protein + carbohydrates.
Supplement Timing Studies
Studies addressing supplementation timing in relation to resistance training are lacking when compared to studies looking at just supplementation or supplementation timing studies with endurance based, aerobic activities. Additionally, the biggest problem with coming to agreements in the effectiveness of nutrient timing is the fact that there are a myriad of co-factors that can affect nutrient timing. Following is an incomplete list of just some of these factors:
- Sex – Males and females have different fuel consumption kinetics
- Training Status – The beneficial effects of supplement timing seems more pronounced in untrained or recreationally active individuals.
- Differing types of nutrients – Supplementation studies mostly examine one timing point.
- Nutrient combinations – Potentiation of effects are possible with several nutrients which makes one single recommendation hard.
- Exercise Type and Intensity – Different types of exercise places different demands on the body which requires a different supplementation regime.
Furthermore many sports science and sports nutrition studies are low in power due to generally low subject numbers. This becomes more evident the more involved the process is. Not everyone likes having blood and tissue samples taken out of them after all! In addition, there has always been the criticism that these studies do not reflect ‘real life’ interactions. However, these controlled environments in which the studies are conducted in provide the most reliable basis in which to make recommendations.
Suppplement Timing is Important
As with all things in nature and life, survival of the fittest is the main dogma. Little gains here and there can add up and may provide you with the edge over your opponents and the people around you. While the concept of nutrient timing is still in its infancy and not at all conclusive, there is definite possibility of an ergogenic effect over and beyond consuming the supplements itself. At the end of the day, it is important to remember that nutrient timing is just one weapon in your arsenal to achieving the results you want and strive for and should not be the be all and end all.
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