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Introduction: Cognitive behavioural therapy (CBT) is widely recommended as the treatment for bulimia
nervosa. CBT addresses dysfunctional cognitions pertaining to body image which are postulated to
maintain disordered eating behaviours. CBT aims to reduce the frequency of binge eating and
compensatory behaviours through promoting a reduction in dietary restriction and the adoption of
regular eating patterns. There is limited evidence investigating the impact of CBT on eating behaviours
and dietary intake. With the non-binge dietary intake of bulimic individuals deemed inadequate,
investigations pertaining to the impact of CBT, which aims to replace binge eating with regular eating,
on dietary intake is of importance. There has been one study investigating the impact of CBT on the
nutritional intake of bulimic individuals which reported an increased number of nutritional inadequacies
following treatment. However, the participant sample investigated did not exclusively receive CBT, with
a proportion assigned to an alternative treatment.
Aim: The overall goal of this study was to evaluate the impact of the 12-week group CBT programme
facilitated by Tupu Ora Eating Disorder Services on individuals with bulimia nervosa. The primary aim
was to investigate the impact that group CBT has on the intake of meals and snacks, specifically aiming
to assess changes in the proportion of individuals adopting a regular eating pattern of 3 meals and 3
snacks daily by the close of treatment. The impact of CBT on binge eating and compensatory
frequencies, nutritional intake, psychopathology, and body weight were also investigated.
Method: Eight individuals with bulimia nervosa were provided with 7-day food diaries at the start and
close of treatment for recording their dietary intake and detailing their intake as a meal or snack. Food
diaries were analysed using FoodWorks 10 Professional and average daily nutrient intakes were
compared with nutrient reference values to assess nutritional adequacy. Binge eating and
compensatory frequencies were collected by self-recall, food diaries and via the Eating Disorder
Examination Questionnaire (EDE-Q) at the start and close of treatment. Eating disorder related
psychopathology was assessed using the EDE-Q and Depression Anxiety Stress Scale (DASS) which
were also provided at the start and close of treatment. Body weight measures were also collected at
these two timepoints.
Findings: Meals and snacks could not be distinguished from one another due to a lack of and
inconsistent recordings within food diaries. No participants achieved 6 eating episodes per day
(reflecting the primary outcome criteria of 3 meals and 3 snacks) at the close of treatment. However,
significant increases in the number of eating episodes and reductions in binge eating frequencies were
achieved. There was disagreement between differing methods of data collection pertaining to changes
in the frequency of compensatory behaviours, with weekly measures indicating no improvements and
monthly measures indicating reductions in such behaviours. The daily non-binge intake of bulimic
individuals significantly increased in energy, fat, and protein (the latter achieved borderline significance)
by the close of treatment, with no change in carbohydrate intake. The contribution of energy from fats
and carbohydrates was imbalanced relative to the acceptable macronutrient distribution, with the former
exceeding recommendations and the latter below recommendations. The average daily non-binge
micronutrient intake for the majority of participants achieved estimated average requirements at the
close of treatment, with some potential inadequacies in calcium, iodine, selenium, zinc, and magnesium.
Despite a decreasing trend, no significant changes were found in the total daily intake (binge intake
combined with non-binge intake) of participants by the close of treatment. Significant improvements
were found in measures of dietary restraint and eating concern as per the EDE-Q, with no change in
concern with body shape, though improvements in concern with body weight were significant at the
10% level. Reductions in measures of stress were found at the close of treatment, with no significant
change in measures of depression and anxiety. No significant change was found in body weight.
Conclusion: Group CBT may offer a promising first line treatment for BN. However, a proportion of
participants may benefit from additional individualised treatment. |
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