None listed
Conditions
Brief summary
There is evidence that public health measures aimed at reducing the burden of obesity have not been effective. Whilst there are several possible reasons for this, including a multitude of competing messages, the overabundance of energy dense food and the near absence of obligatory physical activity, it is likely that the more important reason is the fact that weight appears to be physiologically regulated and defended. This means that using public health measures to combat obesity is not likely to work for obese subjects. What is not yet known is if subjects who are overweight (as opposed to obese), defend weight loss, nor is it known if modest (~5%) weight loss is defended. If overweight or modest weight losses are not defended, it would allow the targeting of public health messages towards the overweight and to focus on modest weight loss in the obese. This study aims to investigate if overweight people defend weight loss as vigorously as obese people, and to determine at what degree of weight loss these physiological changes begin. Overweight and obese people will be recruited and placed on a VLED (very low energy diet) for a period of 12 weeks, aiming to decrease body weight by 15%. Measurements in body weight and a number of biomarkers will be taken at proscribed intervals. All participants will be followed up for a period of two years, to observe weight regain (if any). Gut hormone and other biomarker changes over the trial will be compared between the overweight cohort and the obese cohort, to determine any differences. For both cohorts, changes in gut hormones and other biomarkers will be compared at 5%, 10% and 15% baseline body weight lost, to determine when physiological defences increase.
Interventions
Very Low Energy Diet (VLED) (OptiFast) for 12 weeks. All participants will be placed on OptiFast for a duration of 12 weeks. The OPTIFAST program is a total food
replacement for the overweight. It is intended for use as part of the management of the moderately to severely overweight persons. The OPTIFAST program has been clinically developed and scientifically formulated to totally replace normal food intake. Weight loss is comparable to that achieved by total fasting whilst minimising the comp
Very Low Energy Diet (VLED) (OptiFast) for 12 weeks. All participants will be placed on OptiFast for a duration of 12 weeks. The OPTIFAST program is a total food replacement for the overweight. It is intended for use as part of the management of the moderately to severely overweight persons. The OPTIFAST program has been clinically developed and scientifically formulated to totally replace normal food intake. Weight loss is comparable to that achieved by total fasting whilst minimising the complications of severe ketosis and muscle loss. The OPTIFAST formulation includes high quality protein, sufficient quantities of protein (for nitrogen sparing and to preserve lean body mass), carbohydrates, fatty acids, and follows the Recommended Dietary Intake (RDI) for vitamins, minerals and trace elements. Fortnightly measurements of urinary ketones will be taken to gauge adherence to diet.
Sponsors
University of Melbourne
Study design
Allocation
Non-randomised trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
*Written informed consent obtained *Age 18 – 65 years *BMI 25-50kg/m2 *Stable body weight *In good health
Exclusion criteria
*Body builders *Significant illness *History of recent weight loss *Past history of bariatric surgery *Use of weight affecting pharmacotherapy *Current smokers *History of unstable thyroid disorder
Outcome results
None listed