The effect of low energy availability and low carbohydrate availability on hormone status, metabolism and performance in elite race walkers ('Supernova 4")

Parallel Group design with elite race walkers allocated, according to their preference, to an intervention of short term (5-6 d) exposure to and reversal of: • Low Energy Availability (LEA: ~20 kcal/kg fat free mass/day, with ideal protein intake to the other diets but reduced carbohydrate and fat intake) • High Energy/Carbohydrate Availability (Control: ~40 kcal/kg fat-free mass/day; 65% of energy from carbohydrates, ~15% from energy fats, and 2.1g/kg/d protein) • High Energy/Low Carbohydrate Availability eating (LCHF: 75-80% of energy from fats, <50g/d carbohydrates and 2.1g/kg/d protein) Detailed methodology: The Supernova 4 Research camp will be held over a ~4 week period from January 3-February 3, with final information being collected from the 20 km National Race Walking Championships in Adelaide on February 10. Supernova 4 Research camp will be held at the AIS Canberra campus and will involve live-in accommodation in the AIS Residences in which the dietary interventions and training program will be controlled and monitored. Study funding will support the accommodation, meals and training resources needed to implement the study design. A professional chef will provide all meals to ensure that it is an enjoyable experience, and menus will be personalised to the requirements and special needs/preferences of the athletes. We anticipate that most of the participants will have been involved in previous Supernova Research camps and value both the training camp experience/benefits and the embedded research. Study phases. Phase 1 (Screening): On entry to the Supernova 4 camp, we will undertake screening tests to identify baseline characteristics around aerobic capacity, performance and pre-existing markers of energy availability. This will allow us to identify participants who should be excluded from the study due to frank markers of LEA (e.g. consistency in results of low RMR and low fasting hormone concentrations), and to finalise the allocation of athletes into treatment groups based on intervention preferences and matching of key baseline characteristics. Screening tests will involve • VO2max and economy test according to previous Supernova protocols (key change = test to be undertaken after a standardized meal rather than in fasted state) • DXA assessment of body composition and bone mineral density • Measurement of Resting Metabolic Rate • Screen for fasting concentrations of key hormones (testosterone, estrogen, IGF-1, insulin and T3) to screen for LEA • 10,000 m race walking event conducted by ACT athletics and sanctioned by IAAF (Race 1). This race will be preceded by 24 h of standardised high-carbohydrate, high-energy availability eating, and a high carbohydrate pre-race meal Phase 2 (Harmonisation): All participants will be supervised to consume a Control diet as described above providing high energy availability and high carbohydrate availability to support a structured training program, which will consist of several standardised training sessions (long walk. Hills session, rep session) and sessions of the athlete’s own choosing. This phase will be conducted for 5 d, with the goal of achieving full energy availability for each participant for the baseline test block (Test 1). This diet will be continued throughout Test Block 1, and on completion of the testing, participants will then commence their dietary intervention. Block 1 testing will consist of • DXA/RMR • 25 km long walk test • Hormone profiling/BJ challenge Phase 2 (Intervention) Participants will be supervised to consume one of three personalised diets: LEA, LCHF or Control. Participants will continue to consume these diets for the commencement of Block 2 testing. Test Block 2 will repeat the tests involved in Block 1, with the addition of: • VO2max/economy test (to profile metabolism over a range of exercise intensities as a result of the dietary treatments) • Race 2. Race 2 will involve the same protocol as Race 1, with all subjects resuming 24 h of standardised high-carbohydrate, high-energy availability eating and a high carbohydrate pre-race meal. Phase 3 (Refeeding) In this phase, all participants will resume 5 d of high energy/high carbohydrate diet (i.e. the Control diet)to fully restore fuel availability before undertaking Test Block 3. Test block 3 will be a repeat of Test Block 1, to investigate whether any pertubations in body systems identified in Test Block 2 can be reversed in a similar time period Post-camp It is anticipated that most participants will race in the 2019 Australian Road Racing 20 km championships in Adelaide on February. Participants will be invited to record their self-chosen dietary intake and training in preparation for this race. Researchers will provide support for participants during the race (feeding from aid stations) and record race behaviours (fluid intake, carbohydrate intake, BM changes) and outcomes to provide feedback about the achievement of their self-chosen race nutrition goals. This will form descriptive information on practices of elite endurance athletes during race conditions, and provide opportunity for insight into the effect of the camp involvement on race performance Test Protocols: To avoid the need for an excessively lengthy ethics application and to aid in understanding the project as a whole, this application will provide an abbreviated description of data collection within the 5 testing protocols , with the identification of new testing variables and study collaborations not previously involved in SN 1-3. 1. DXA and RMR: Duplicate measurements of Resting Metabolic Rate will be undertake on participants under fasting, resting conditions according to AIS Best Practice Protocols. This will be followed by a DXA assessment of body composition also undertaken according to AIS Best Practice Protocols by an accredited DXA technician. Bioimbedance will be used to estimate total body water at the same time to check for artefacts in the DXA measurements of Lean Body Mass created by the loss of muscle glycogen and its bound water stores. This protocol will allow us to investigate the true effects of the dietary interventions on resting metabolic rate, as well as determine whether a potential artefact can cause a false interpretation. 2. 10,000 m race. Athletes will consume a standardised high carbohydrate pre-race meal (2 h pre-race) and follow their self-chosen race warm up/preparation strategies. • In the case of the LCHF diet group, the warm up will include a brief laboratory test of economy and fuel utilisation at 2 exercise intensities, to allow the investigation of changes achieved separately by the 6 d of LCHF diet and 24 h restoration of glycogen. Race logistics do not allow this information to be collected from all participants; and prioritisation will be given to the LCHF group since the capacity of “fat-adapted” muscle to utilise glycogen if it is restored remains an unresolved issue. In this case, direct comparison can be made between the VO2max test days and the Race days, to show shifts in muscle fuel use due to chronic adaptation and acute fuel stores • All participants will provide capillary blood samples to monitor glucose, lactate and ketones pre, and post-race 3. VO2max/economy test Participants will consume a meal according to their dietary phase (e.g. Control or intervention), 2 h prior to the test. The test will involve the standard 4 stage + ramp to fatigue undertaken in previous SN camps and as routinely used in distance athletics in Australia • Capillary blood samples will be collected post-meal and at the end of each stage of the test to measure blood metabolites 4. 25 km long walk protocol • Hybrid Lab-Field test with segments in laboratory and remainder as 5 km loops around AIS • 5 min lab (~1 km) segments (0-1, 6-7, 12-13, 18-19, 24-25 km) to monitor fuel use and economy at 2nd speed of economy test (~ 50 km race speed) • A mixture of venous and capillary blood samples will be taken to minimise total blood volume and allow investigation of a range of variables • New parameters add to 25 km walk test: Metabolome; Reticulocytes for Athlete Biological passport; Salivary/Blood testosterone and cortisol. 5. Hormonal profiling and Beetroot juice challenge: Participants will be observed for a 6-7 h period at rest, involving early morning and fasted blood samples (hormone pulsatility), plus the response to a meal and a beetroot juice supplement challenge. In addition to blood samples, we will collect fecal and saliva samples for investigation of changes in the microbiome.