None listed
Conditions
Brief summary
This was a non-blinded, 2 phase, randomised dietary intervention trial investigating if the rate of weight loss is important in long-term weight maintenance; if physiological adaptations encouraging weight regain are different with different rates of weight loss; if these adaptations reverse with time and if psychological profile can help us choose if slow or rapid weight loss is best suited to a particular psychological profile. Participants were obese (BMI 30.0 - 45.0 kg/m2) and aged between 18 and 70 years. Following telephone and onsite screening 200 subjects commenced phase 1 of the trial (weight loss phase) and were randomised by strata to either a rapid or gradual weight loss program. During this phase appointments were at the same interval with similar quality of dietary education materials for all subjects. Projected weight-loss graphs were personalised to each participant and utilised at each visit to compare expected and actual weight-loss achieved at each time point. Both the rapid and gradual weight loss group had prescriptions for the same overall energy deficit (105,000 kcal or 430,500 kJ). The rapid weight loss group were asked to accumulate the deficit over 3 months while the gradual weight loss group had to accumulate the same deficit over 9 months. In both treatment groups, participants were instructed to undertake at least 30 minutes a day of mild to moderate intensity exercise (e.g. brisk walk). Participants attended fortnightly for individual consultations with the same qualified dietitian. During these visits, they had anthropometry measurements taken and were given dietary counselling based on their individual needs in order to remain on their projected curve and achieve their target weight of 15% weight loss. All participants who successfully achieved 15% weight loss in phase 1 were eligible to enter into phase 2 (weight maintenence phase) of the trial. During phase 2 participants followed a weight maintenance diet which was individualised for each participant and similar to the Australian Guidelines for Healthy Eating(Smith A 1998). Individual sessions were conducted with the study dietitian quarterly for the three years following phase I.
Interventions
Phase 1:Weight Loss Phase
Arm 1: Rapid Weight Loss Group- subjects will consume a commercially available VLCD preparation (Optifast(R)) for three months. During this phase 3 meals a day (Breakfast, Lunch and Dinner) will be replaced with a nutritionally sound meal replacement in a liquid form called Optifast (R). To administer these liquid meals participants will add the Optifast(R) powdered sachet (40grms) to 200ml of water and shake vigrously in a closed container. The Optifast shakes are app
Phase 1:Weight Loss Phase Arm 1: Rapid Weight Loss Group- subjects will consume a commercially available VLCD preparation (Optifast(R)) for three months. During this phase 3 meals a day (Breakfast, Lunch and Dinner) will be replaced with a nutritionally sound meal replacement in a liquid form called Optifast (R). To administer these liquid meals participants will add the Optifast(R) powdered sachet (40grms) to 200ml of water and shake vigrously in a closed container. The Optifast shakes are approximately 150-200 calories per shake. The Optifast shakes contain all the energy, macro and micro nutrients required to reach recommended daily intakes (RDIs). Participants will also have biweekly contact with the dietician who will instruct the subjects to follow a VLCD. During this weight loss phase participants will be required to lose at least 15% of their body weight (approximately 1.50kg/week). Arm 2: Gradual Weight Loss Group- subjects will be instructed bi-weekly by a dietician to follow a weight loss program similar to the Australian Guide to Healthy Eating and at least one meal a day will be replaced with a optifast(R) meal for nine months. During this weight loss phase subjects will be required to lose at least 15% of their body weight (approximately 0.5kg/week). Phase 2: Weight Maintenance Phase All participants will be monitored for the following 3 years post phase 1.
Sponsors
The University of Melbourne
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
Inclusion criteria The criteria for inclusion in the trial are: *Healthy men and women aged 18-70 years with a desire to lose weight *Weight stable for 3 months *BMI >30kg/m2
Exclusion criteria
*Pregnancy or breast feeding *History of surgical procedures or laxative abuse for weight loss *The use of any VLCD or weight lowering drugs in the past three months *Known major weight change in the previous six months (>10% body weight) *Inability to attend scheduled examinations and visits *Inability to follow the study instructions, or unlikely to be compliant to the dietary prescription provided *For females taking an oral contraceptive pill: dose must have been stable for the past three months *For females using hormone replacement therapy: dose must have been stable for past 3 months *For participants receiving thyroid preparations or thyroxin treatment: dose must have been stable for the past three months *Surgical intervention planned during the study * Any recent (less than six months) cessation of smoking and current smokers *Participation in another study, or administration of any investigational drug in the past three months *Uncontrolled and clinically significant disease or known malignancy that could interfere with the study conduct *Presence of any clinically significant renal or endocrine disease (including diabetes) according the Investigator or as revealed by screening blood tests
Outcome results
None listed