The effect of Gymnema sylvestre-containing mints on sugar consumption in adults with a sweet tooth - the Liberate From Sugar, Mate! study

INTERVENTION: For an initial 14 days all participants will be treated with a placebo i.e. without the active ingredient. Participants will be required to consume the placebo mint (see below note about mints) three times per day for 14 days, at specified time points (mid‐morning, mid‐afternoon, post‐dinner). Participants will then be randomly allocated into two experimental groups which they will be in for the following 14 days: either the Systematic or Ad‐lib groups. After these 14 days, the participants will undertake the second intervention trial (i.e., “crossover” ‐ if participants were allocated to Systematic intervention for the first 14 days, they will then follow the Ad‐lib intervention for the next 14 days. Intervention B: Systematic intervention ‐ Materials: Gymnema sylvestre (GS) mints (see below note about mints) compliance diaries ‐ Procedures / activities: participants will undertake a 14‐day GS mint intervention where they are asked to 1) consume the GS mint three times a day at specified time points and 2) complete the compliance diary daily. ‐ Who will deliver intervention: student dietitians Imogen Nelson and David Hsiao ‐ Mode of delivery: mints will be provided for participants at visit 2 or 3 (depending on group allocation as per cross over design), and participants will then follow the intervention for 14 days at home. ‐ Number of times the intervention will be delivered and their duration, intensity or dose: three mints per day for 14 days. ‐ Location where intervention occurs: participant’s homes. Intervention C: Ad‐lib intervention ‐ Materials: GS mints (please see below note about mints), compliance diaries ‐ Procedures / activities: Participants will undertake a 14‐day GS mint intervention where they are CONDITION: Diet and Nutrition ‐ Other diet and nutrition disorders Mental Health ‐ Studies of normal psychology, cognitive function and behaviour Metabolic and Endocrine ‐ Diabetes Overweight;Diabetes mellitus;Obesity; ; Overweight ; Diabetes mellitus ; Obesity INCLUSION CRITERIA: Eligible participants for the study 1) have a self‐reported sweet tooth, 2) can come onto the Massey University Albany campus for four separate visits, 3) are in general good health. PRIMARY OUTCOME: Ad‐libitum intake of GS‐containing mints as assessed by compliance diaries designed for the study.[Days 16 ‐ 29 OR days 31 ‐ 44 after commencement of data collection, depending on which group the participants are randomly assigned to as per cross‐over design. Compliance diaries will be completed daily on each day of interventions A, B and C (i.e. days 1 ‐ 14, 16 ‐ 29, and 31 ‐ 44)] Changes in food cravings as assessed by a validated food cravings questionnaire called the Food Cravings Questionnaire (Cepeda‐Benito, Gleaves, Williams, & Erath, 2000); ; [Days 0, 30 and 45 after commencement of data collection. In other words, day 0 = baseline; day 30 = after intervention B or C; day 45 = final, after crossover to intervention C or B.; ; ] Motivations to eat sugar sweetened food as assessed by individual, semi‐structured interviews designed for the study with volunteers.; [Days 0, 15, 30 and 45 after commencement of data collection. In other words, day 0 = baseline; day 15 = after intervention A; day 30 = after intervention B or C; day 45 = final, after crossover to intervention C or B.; ] SECONDARY OUTCOME: (Primary outcome): changes in beverage intake as assessed by a beverage intake questionnaire. The beverage intake questionnaire used is called the Brief 15‐Item Beverage Intake Questionnaire (BEVQ‐15) and is adapted specifically for this study from Hedrick et al.'s original validated BEVQ‐15 questionnaire (2001).[Days 0, 30 and 45 after commencement of data collection. In other words, day 0 = baseline; day 30 = after intervention B or C; day 45 = final, after crossover to intervention C or B. ; ] (Primary outcome): changes in food intake as assessed by a food frequency questionnaire. The questionnaire used is called the Food Frequency Questionnaire and is adapted specifically for this study from Mumena & Kutibi's validated Food Frequency Questionnaire (2022) [Days 0, 30 and 45 after commencement of data collection. In other words, day 0 = baseline; day 30 = after intervention B or C; day 45 = final, after crossover to intervention C or B.] Changes in body composition (i.e. change in body fat % and change in total body weight) as assessed via bioelectrical impedance (BIA). The BIA being used in this study also weighs body weight (it has a function enabling it to act as a set of digital scales in addition to BIA). ; [Days 0, 30 and 45 after commencement of data collection. In other words, day 0 = baseline; day 30 = after intervention B or C; day 45 = final, after crossover to intervention C or B. ; ] Hunger levels as assessed via Visual Analogue Scales. ; [Days 0, 15 and 30 after commencement of data collection. In other words, day 0 = baseline; day 15 = after intervention A; day 30 = after intervention B or C. ; ] Levels of desire for sugar sweetened food as assessed via Visual Analogue Scales.[Days 0, 15 and 30 after commencement of data collection. In other words, day 0 = baseline; day 15 = after intervention A; day 30 = after intervention B or C. ; ] Self‐reported pleasure from sugar sweetened food as assessed via Visual Analogue Scales.[Days 0, 15 and 30 after commencement of data collection. In other words, day 0 = baseline; day 15 = after intervention A; day 30 = after intervention B or C. ; ]