Within any 24hr period, our body’s energy systems and muscles have varying requirements depending on activity within the period. The muscles are actively involved in the production of energy, periods of recovery and periods of growth/repair. For optimised metabolic response and therefore optimised performance, it is important that the correct types of nutrients are delivered in appropriate macronutrient partitions at the right times.
Depending on your nutrient requirements and desired metabolic response the body may produce glycogen (muscle stored glucose) to replace lost energy stores or synthesize protein for muscle repair/growth. Each of these functions requires different nutrients and often different nutrient ratios at the right time for the optimum response. This approach can greatly enhance recovery; improve muscle growth and repair, strength, explosive power and endurance.
Over the past 20 years, sports nutrition has emphasised different macronutrients for different types of athletes. Protein has been shown to highly effective for strength athletes and that their protein requirements are higher than others for improved strength and development. Carbohydrates, particularly simple (sugary) carbohydrates have been held in high regard in the form of sports drinks for many endurance and performance athletes.
Recent research shows that whilst these two main nutrients are undoubtedly valuable for all athletes, the key to improved results is not only in ensuring the body receives enough of these nutrients but the fact that for optimised response the body requires specific balances of nutrients (such 2:1 carb/protein for recovery) but also the time frames within which the nutrients are consumed and the many co-factor nutrients (such as vitamins and minerals) contained within real food are important for optimised assimilation and results.
Basically, timing, as in many things, is everything!
In simple terms, this can be broken down into three important phases, energy, recovery and repair.
The Energy Phase:
Often referred to as the loading phase and wrongly termed carb loading. This period is in effect the time where any athlete primes the body for exertion whether this is in the gym, at a training session or prior to a game or competitive event.
The importance here is to ensure the athlete attends with fuel tanks fully charge and in an optimum condition for activity, a primed state. Whilst most athletes are aware of the importance of glycogen/energy stores it is important to note than quickly drinking a few bottles of sports drink prior to the event is not only not an effective protocol but can be counterproductive.
Glycogen stores (the body’s fuel tank) need to be replenished over time and glycogen retention is optimised by the use complex carbohydrates (such as rice & oats) and other macro and micronutrients such as protein, amino acids and vitamins. Research has shown that when consumed in the correct ratios and over time the body can spare muscle glycogen, achieve greater endurance, blunt the rise of cortisol in response to exercise (reducing muscle damage) and prime the body for faster recovery.
It is worth noting that glycogen cannot be manufactured and stored by the body without water, so correct levels of hydration are important.
The Recovery Phase (Anabolic Window)
This is the post game, competition or training all important window for optimum recovery. This is where the presence of the correct balance of nutrients within the 45 minutes post event starts the process of repairing damaged muscle fibres with protein and the glycogen stores can be replenished.
Post-exercise muscle cells are extremely sensitive to the anabolic effect of the hormone insulin. This sensitivity peaks between 15 and 45 minutes post-exercise and then dramatically drops off to zero within two hours at this point the cells become insulin resistant and this can dramatically slow glycogen recovery and the repair and synthesis of new muscle fibres.
Adopting the correct protocol during this period can extend the anabolic window and counter the negative effects and increase the body’s ability for growth and regeneration.
The consumption of the correct balance of carbohydrates and protein during this period has a highly synergistic effect. The protein can assist in the production and retention of glycogen and carbohydrates can stimulate protein synthesis other co-factors such as vitamin C & E can also speed up the whole recovery process.
The Repair Phase (Growth and Regeneration)
This period is really an extension of the recovery stage and the start of the priming steps for the next training session or event. During this time the muscle enzymes get to work increasing the contractile proteins and increase and repair the muscle fibres and replenish the depleted muscle glycogen.
In a sense, the Repair / Growth phase has two parts, the first being the extension of the recovery / anabolic window for four hours post-event where the correct balance of proteins and carbohydrates maintain increased insulin sensitivity and the anabolic state for growth and repair.
In the second section, it is important to maintain a positive nitrogen balance and stimulate protein synthesis for protein turnover and recovery. Here research indicates that slightly higher levels of protein consumption and the correct times are important for strength athletes particularly.
Putting it into practice
For more detailed information on the specific protocols putting it into action and example programs, we will be posting specific papers for each Phase stay posted. Website registered members can partake in discussion groups on this matter and sport-specific protocols.
- Zawadzki, K.M., Yaspelkis., III, and Ivy, J.L., “Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise” Journal of Applied Physiology, 72:1854-1859, 1992.
- Suzuki, M., Doi, T., Leee, S.J., et al., “Effect of meal timing after resistance exercise on hindlimb muscle mass and fat accumulation” Journal of Nutritional Science and Vitaminology, 45:401-409, 1999.
- Gleeson, M., Lancaster, G.I., and Bishop, N.C., “Nutritional strategies to minimize exercise-induced immunosuppression in athletes” Canadian Journal of Applied Physiology, 26 (Suppl): S23-S35, 2001
- Ivy, J.L., “Dietary strategies to promote glycogen synthesis after exercise”: Canadian Journal of Applied Physiology, 26 (Suppl): S236-S245, 2001.
- Ivy, J.L., Katz, A.L., Cutler, C.L., et al., “Muscle glycogen Dietary synthesis after exercise: effect of time on carbohydrate ingestion”: Journal of Applied Physiology, 64: 1480-1485, 1988.
- Levenhagen, D.K., Carr, C., et al., “Postexercise nutrient intake timing in humans is critical to the recovery of leg glucose and protein homeostasis”, American Journal Physiology, 280: E982-E993, 2001