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theses

Behavioral weight loss interventions are effective at achieving clinically significant weight loss, though weight regain is common because dietary adherence is problematic. Studies report that taste is the primary determinant of food intake, so accounting for individual variability in taste preferences may improve adherence to a weight loss regimen. Genetically mediated sensitivity to the bitter compound, 6-n-propylthiouracil (PROP) associates with differences in perception and preference for basic tastes and oral textures, most notably fat. Previous research from our laboratory has revealed that PROP non-taster (NT) women exhibit higher preferences for, and daily intake of, fat when compared to PROP super-taster (ST) women, suggesting that a single dietary approach may not be appropriate for everyone attempting to lose weight. In our study, we randomized PROP ST and NT women with obesity to a low-fat (LF) or low-carbohydrate (LC) diet within a 6-month behavioral weight loss intervention to assess whether prescribing a diet complementary to their taste preferences would improve dietary adherence to promote greater weight loss. As an ancillary study, we investigated whether changes in taste perception and liking for sweet and fatty foods would occur concomitantly with weight loss throughout the intervention. For the main study, results showed that PROP NT women randomized to the LC diet lost more weight than NT women randomized to the LF diet (-8.5 ± 0.5 kg vs. -6.6 ± 0.5 kg, P = 0.008), and that weight loss was comparable for ST women randomized to either diet (-8.9 ± 0.5 vs. -8.8 ± 0.4, P = 0.35). Dietary analyses indicated that energy and fat intake were consistent with the dietary prescriptions, though were not associated to weight loss. These findings suggest that pre-screening for PROP status may be an effective tool for improving weight loss outcomes in women, but further research is necessary to understand the dietary patterns of NT and ST women within a weight loss context. For the ancillary study, analyses detected a change in liking, but not perception, for sweet and fatty foods. By 6 months, liking increased for tasted foods with less sugar and fat, irrespective of diet. These findings show that gradual weight loss is capable of modifying taste preferences, which could serve to influence food selection patterns and be implicated in weight loss maintenance.

ETD_7635

Ph.D.

Includes bibliographical references

by Brenda Burgess

doi:10.7282/T34Q7X80

ETD doctoral

The author owns the copyright to this work.