A Digital Approach to Improving Carbohydrate Periodisation Behaviours in Athlete: SMART+ Study

The study is conducted in two consecutive parts.

For part one, to assess the feasibility and acceptability of the digital approach, participants are recruited to use the app for 6 weeks and were given coach support, where coaches message (MesC) and call (ad-hoc Call) and the participants. A control group (no app) is also separately recruited to compare with the menu planner group.

For part two, to gain better understanding on the strategy to implement coach support with the menu planner app according to app engagement, a pilot multiple assignment randomized trial (SMART) design is conducted. Participants are equally randomised to either receive a stringent engagement criteria strategy or relaxed adherence criteria strategy. A stringent engagement criteria strategy requires the user to use the app at least twice a week at stage 1, and at least 3 times a week at stage 2 to be considered a responder at stage 1 and stage 2 (R1 and R2).

A relaxed engagement criteria strategy requires the user to use the app at least once a week in week 1 of using the app at stage 1, and at least 2 times a week at stage 2, to be considered a responder at stage 1 and stage 2 (R1 and R2). Non-responders for both criteria strategies at stage 1 and 2 (NR1 and NR2) will be re-randomised to either continue with the app only or additional coach support (MesC + ad-hoc Call).

Timeline wise,

Stage 1: Participants will first receive app for 1 week and will be categorised as responder (R1) or non-responders (NR1) at the end of the 1 week.

Stage 2: Responders to stage 1 (R1) will continue with the menu planner for 1 week. Non-responders to stage 1 (NR1) will either continue with the menu planner or receive additional coach support (MesC + ad-hoc Call) for 1 week. Participants are categorised again as responder (R2) or non-responders (NR2) at the end of the week.

Stage 3: Responders to stage 2 (R2) will only have menu planner for 2 weeks. Non-responders to stage 2 (NR2) will either have menu planner only or receive/continue with additional coach support (MesC + ad-hoc Call) for 2 weeks.

The SMART trial will take a total of 4 weeks to complete and have up to two randomisation points per participant. All re-randomisations are done at 1:1 allocation ratio.

• MP (Behavioral): The app-based menu planner (MP) given to the participants has an automated carbohydrate periodisation menu planning tool, an educational and motivational nutrition content (infographics, video and text articles), and recipes. Participants using the app will input their training schedule into the app to produce their own menu plans. The behaviour change techniques (BCT) underlying the intervention are goal \& planning, feedback \& monitoring, shaping knowledge, natural consequences, comparison of behaviour, comparison of outcome, associations, repetitions, reward \& threat, regulation and antecedents.
• Call (Behavioral): A 30-45 minutes coaching consultation telephone/Skype call from the nutrition coaching to give social support. The BCT underlying the intervention is goal \& planning, social support, natural consequences.
• MesC (Behavioral): Nutrition coach-led messaging (MesC) is where the mobile app (MP) has the text messaging feature activated, and the nutrition coach proactively initiates a conversation via text messaging up to three times a week to offer nutrition support to the participant. The BCT underlying the intervention is goal \& planning, social support, natural consequences.

Primary outcomes

• Success rates of carbohydrate periodisation behaviour at week 4, 6 [At week 6 (for part I of study) and week 4 (part II of study)]: A binary success of whether dietary periodisation behaviour has improved in the participant measured by the "periodisation behaviour questionnaire" (in the process of submitting the paper on validation of questionnaire). The scale is 1- does not periodise, 2-periodises energy but not carbohydrate, and 3-periodises both. Higher score indicates better periodisation behaviour. Only score of 3 is considered success.

Secondary outcomes

• Change in dietary self-efficacy from baseline to week 4, 6 [At baseline (week 0) and at week 6 (for part I of study) and week 4 (part II of study)]: The dietary self-efficacy will be assessed using a self-efficacy scale. This questionnaire have been validated in the general population (Stich, Knauper and Tint, 2009). The scale is a 5-point scale from 1 for not confident at all, to 5 for very confident. Higher score indicates higher self-efficacy.
• Change in beliefs about consequences from baseline to week 4, 6. [At baseline (week 0) and at week 6 (for part I of study) and week 4 (part II of study)]: The beliefs about consequences scale has not yet been validated but has been adapted from previous research on beliefs about capabilities by Wallin, Boström and Gustavsson (2012). The scale is a 5-point sale from 1- not at all to 5- extremely. Higher scores indicate higher beliefs about consequences.
• Change in body weight from baseline to week 4,6 [Baseline(week 0) and at week 6 (for part I of study) and week 4 (part II of study)]: Self-reported weight (in kg/lbs) collected at baseline and at week 6 (for part I of study) and week 4 (part II of study)

Other outcomes

• Personality traits on a BFI-2S questionnaire at baseline [At baseline (week 0)]: The BFI-2S questionnaire (Soto and John, 2017) is a validated questionnaire to assess the Big Five Personality domains of an individual.
• Level of need for autonomy on the nutrition causality orientation scale at baseline. [At baseline (week 0)]: The nutrition causality orientation scale is a measure of the need for autonomy in nutrition-related decisions. It is not yet validated but is adapted from previous research on the validated health causality orientation scale (Smit and Bol, 2020). The scale is a 7-point scale, with 1 being strongly disagree to 7 being strongly agree.

Sex: All, ages: 18 Years to 55 Years, accepts healthy volunteers

Inclusion Criteria:

* Have access to a personal smart phone.
* An elite or training athlete.
* Have a performance related weight loss or weight maintenance physical goal.
* Do not have or have not have a history of eating disorders or disordered eating.

Exclusion Criteria:

* Participants with a medically diagnosed history of eating disorders or disordered eating will be asked to self-exclude from the study.

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