A Review of the Effect of Dietary Composition on Fasting Substrate Oxidation in Healthy and Overweight Subjects.

AIM: The purpose of this review was to assess existing evidence on the effects of chronic dietary macronutrient composition on substrate oxidation during a fasted state in healthy and overweight subjects. METHODS: A systematic review of studies was conducted across five databases. Studies were included if they were English language studies of human adults, ≥19 years, used indirect calorimetry (ventilated hood technique), specified dietary macronutrient composition, and measured substrate oxidation. RESULTS: There was no evidence that variations of a typical, non-experimental diet influenced rate or ratio of substrate utilization, however there may be an upper and lower threshold for when macronutrient composition may directly alter preferences for fuel oxidation rates during a fasted state. CONCLUSION: This review indicates that macronutrient composition of a wide range of typical, non-experimental dietary fat and carbohydrate intakes has no effect on fasting substrate oxidation. This suggests that strict control of dietary intake prior to fasting indirect calorimetry measurements may be an unnecessary burden for study participants. Further research into the effects of long-term changes in isocaloric macronutrient shift is required.

Relative validity of a brief Fat and Fibre Behaviour Questionnaire in a population of overweight and obese breast cancer survivors: A note of caution.

AIM: Dietary intake assessment is often difficult in research contexts because of time and resource constraints and participant burden. Valid, reliable and brief assessments of dietary behaviour are needed. Additionally, examination of instrument performance in a variety of populations is needed. This study assessed relative validity and responsiveness to change of the Fat and Fibre Behaviour Questionnaire (FFBQ) in a population of breast cancer survivors compared with dietary intake measured by 24-hour recalls. METHODS: Data were collected at baseline and six months after baseline of a six-month, randomised controlled trial that evaluated a telephone-based behavioural weight loss intervention (n = 45) compared to usual care (n = 45) among overweight and obese breast cancer survivors. The FFBQ's total index, fat index and fibre index were assessed for relative validity against two 24-hour recalls (Pearson's correlations). Responsiveness to change was assessed as intervention group change divided by standard deviation of usual care group change. RESULTS: Pearson's correlations of the fat index with fat intake measures ranged from -0.09 to -0.30 (P < 0.05) at baseline and from -0.19 to -0.28 (P < 0.05) for dietary change. Correlations of the fibre index with unadjusted and energy-adjusted fibre intake measures (0.25-0.32, P < 0.05) were significant at baseline only. Both the FFBQ and 24-hour recall were responsive to fat-related dietary changes and not responsive to fibre-related changes. CONCLUSIONS: The FFBQ showed small to medium relative validity against 24-hour dietary recall for assessing fat and fibre dietary behaviours and changes in dietary fat, and was responsive to fat-related dietary changes in this population.

Telephone-delivered weight management services in the hospital outpatient setting: Decision-makers' perceptions of their use in routine practice.

AIM: Providing effective weight management services to the growing number of overweight or obese hospital patients necessitates long-term service provision; however, it is arguably not within the acute-care hospital remit to provide such extended services. Referral to community-based programs is required to provide continuing weight management services. The Get Healthy Service is a free six-month, telephone-delivered lifestyle program, now offered in several states of Australia with potential for wide population reach. However, health practitioner referral into the service has been low. The study aimed to examine awareness and suitability of the Get Healthy Service for referral of hospital outpatients for weight management, among key health-care decision-makers. METHODS: Nine key decision-makers from metropolitan and rural Queensland Health hospitals took part in semi-structured telephone interviews that were audio-recorded (January-July 2014), transcribed verbatim and thematically analysed. RESULTS: Interviews revealed that most decision-makers had limited awareness of the Get Healthy Service but perceived the telephone service to be suitable for patient referrals. Incorporating Get Healthy Service referrals into patient care was seen to be potentially valuable and relatively easy to implement, with most interviewees suggesting that they would provide a Get Healthy Service brochure to patients who could then self-refer into the service. CONCLUSIONS: The Get Healthy Service provides a referral model for weight management service provision that appears feasible for use in Queensland hospital settings. Increased awareness and a more integrated approach to referrals would likely result in improved enrolment to the service, with future research needed to demonstrate this.