Periodised nutrition: what is it?
Many posts from athletes and nutrition podcasts discuss the importance of periodised nutrition to support training demands, performance and recovery. So what is it?
Juekendrup (2017) refers to periodised nutrition as the strategic combined use of exercise training and nutrition, or nutrition only, with the overall aim to obtain adaptations that support exercise performance. In the sport of triathlon, where athletes juggle 3 different disciplines, plus strength training, and no doubt work and family, ensuring calorie demands are met is no easy task. A recent systematic review and meta analysis by Gallant et al., (2024) examining 59 studies and over 6000 athletes found that in endurance sport, overall Low Energy Availability (LEA) was at around 44.7%, 44.2% females and 49.4% male athletes, which would suggest that endurance athletes are at a high risk of suffering the consequences of low energy availability. This is not surprising considering high training volumes, appetite suppression after hard sessions, plus travel, competition, and well, just life! The consequences are poor sleep, poor recovery from sessions, not to mention the impact on performance. Long term chronic LEA can also result in RED-S, the consequences of which are outlined in \mountjoy et al, (2018) consensus statement. There are numerous combinations of periodising nutrition, however here we are just going to focus on the two most common strategies used by athletes to manipulate fuel, and the pros and cons of these methods, and how to ensure we fuel adequately to ensure we have Optimum Energy Availability (OEA)
Fasted training: There are numerous ways in which athletes complete sessions in a fasted or low glycogen state. Such as early in the morning with no fuel before hand, their last meal being the evening before, or if they train twice a day, if carbohydrates are limited between session 1 and 2, or if they regularly follow a low carbohydrate high fat diet. The amount of muscle glycogen will vary depending on the extent to which carbs have been limited, however liver glycogen will be low. The training benefits will be enhanced fat oxidation, improved metabolic flexibility and for some athletes it will improve gut comfort (if they do not like training with food in their gut). BUT it also runs the risk of increasing the chance of LEA, a reduction of training quality, a feeling of increased RPE and can increase cortisol and stress load. Also, if fueling post session is inadequate, AND there are two training sessions in the day, then there is a risk of protein muscle breakdown. Therefore before you disappear out the door with no fuel, consider the goal of your training session, length and where you are in your training block. If its an easy 60-90mins in a recovery week, then there are definitely benefits, however if you are mid heavy training block, or heading into your race season or it's a quality 90+ session, consider getting up a bit earlier to ensure you are fueling for the work required. Then post session, make sure you recover, replenish your muscle glycogen, and consume protein to help muscle repair. As no doubt there will be another session later in the day.
Train High: Consuming a high carbohydrate meal pre training sessions. This will ensure you can work above 65% VO2 max so ideal for hard quality sessions as greater adaptation to the session should occur, RPE will feel lower and increased improvements in race pace intensity. It can help to reduce hormonal stress, as high CHO availability blunts cortisol and adrenaline responses, which means better recovery, improved sleep, lower immune suppression, and more stable menstrual function in female athletes. With back to back sessions or in periods of heavy training it can also protect against muscle protein breakdown. Also, practicing with carbohydrates throughout longer training sessions can help train the gut to absorb and tolerate higher intakes, but this does not need to be practiced all the time, a few key sessions 8-10 weeks out from key races is key, otherwise your training sessions can become very costly!. The cons of ensuring high carbohydrate are that it will reduce fat oxidation adaptations, there is the potential for GI issues, such as bloating, gas cramps if consuming too close to a hard session, or the wrong type of carbohydrate, and in the off season, or periods of low training, if could result in over fuelling or weight gain. It also requires planning ahead to ensure the correct fuel is consumed pre during and post sessions, which is not always easy with busy lifestyles and often tricky for early starts.
As you can see, just as your training changes across the season, your nutrition needs to support these changes for optimum performance. Athletes will spend hours planning, executing and analysing their data, but will forget to fuel the pre- morning session, or run out the door after a hard session without fueling, which will undermine that effort, and impact recovery. Therefore taking time to understand the purpose of the session and fueling correctly is key to remain in energy balance, and reap the rewards of your hard work. If you find that you do not have the hours in the day to invest in this process, then let me know, and we can find a way to support your training and nutrition to ensure you maximise your goals.
Gallant TL, Ong LF, Wong L, et al. Low energy availability and relative energy deficiency in sport: a systematic review and meta‑analysis. Sports Med. 2024. doi:10.1007/s40279‑024‑02130‑0
Jeukendrup AE. Periodized Nutrition for Athletes. Sports Med. 2017;47(Suppl 1):51-63. doi:10.1007/s40279-017-0694-2
Mountjoy M, Sundgot‑Borgen JK, Burke LM, et al. IOC consensus statement on relative energy deficiency in sport (RED‑S): 2018 update. Br J Sports Med. 2018;52(11):687‑697.