Sweetkick : a qualitative investigation into the effect of Gymnema sylvestre on motivations to consume sweet foods : a thesis completed as part of the requirements for Master of Science in Nutrition and Dietetics at Massey University, Albany Campus Auckland, New Zealand

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Background: Although excessive sugar-sweetened food (SSF) consumption increases obesity risk, global consumption is inappropriately high. Complex motivations to eat these foods may contribute to high sugar intakes. The herb Gymnema sylvestre (GS) has been shown to reduce SSF consumption, but its effects on motivations to eat SSF are currently unknown. Objectives: To conduct a qualitative investigation into the motivations of adults to eat SSF whilst participating in a placebo-controlled randomised cross-over trial investigating the effects of GS on SSF consumption. Methods/Design: Placebo-controlled randomised cross-over trial with seven participants (mean age of 34.7 ± 13.8 years, two males, five females). Participants tested a placebo (administered three times a day in between meals, i.e., administered systematically, i.e., PLAC-SYS) for an initial 14 days, before they were randomly allocated to one of two GS treatment groups for a second 14-day period. Treatments consisted of administration of GS-containing mints systematically (three times a day in between meals, i.e., GS-SYS treatment), or administration of GS-containing mints ad-libitum (up to six times a day, at times completely controlled by participant, i.e., GS-ADLIB treatment). Participants were then crossed over to the treatment they had not tried yet for a final 14-day period. Each participant completed four interviews at baseline and after each 14-day testing period to capture thoughts, feelings and opinions about how motivations changed, how in control participants felt about SSF intake, and how effective treatments were at changing SSF intake. Interview transcripts were uploaded to NVivo for analysis. Themes and sub-themes were identified, linked and explored to ascertain how participants' motivations to eat SSF were affected during each arm of the trial, and what was influencing their motivations. Results: At baseline, adult motivations to eat SSF were psychological, external, habitual, hedonistic and physiological in origin; adults were also motivated to avoid SSF for the same reasons (except none avoided SSF out of habit). Baseline motivations to eat and avoid SSF were influenced by deliberate decisions to change lifestyles and external factors such as occupations. During the different testing phases of the study (i.e., PLAC-SYS, GS-SYS and GS-ADLIB) participants' motivations were affected by the treatments (GS and placebo), as well as external factors (such as occupations) but at all stages participants were still motivated to eat SSF because of pleasure-seeking reasons. Compared to PLAC-SYS, the GS-SYS and GS-ADLIB treatments affected motivations more because they reduced the pleasure derived from SSF to a greater degree, and because they enhanced the participants' mindful eating. Four of seven participants preferred GS-SYS to GS-ADLIB because they felt it tasted better and was more effective at changing behaviours related to SSF intake. Participants also reported their self-control levels of SSF intake changed by administration of GS-ADLIB and through the influence of external factors (but not GS-SYS or PLAC-SYS). However, participants overall reported varying levels of control during the study, mostly because of changes in their lives (i.e., external factors) rather than the effects of GS-ADLIB. Conclusion: Compared to placebo, GS administered systematically and ad-libitum may increase motivations to avoid SSF. The herb may be a useful addition to interventions that already utilise mindful eating, as it could help enhance these practices by increasing the time frame between initially being motivated to eat SSF and actually eating the SSF. Gymnema sylvestre may also be useful when used as part of larger interventions because there are many external factors that affect how in control individuals feel over SSF intake, and when administered ad-libitum, GS may help enhance self-control levels. Therefore, lifestyle interventions that provide holistic support to navigate changing external factors combined with GS may be particularly effective in reducing total SSF intake.