Obesity
Conditions
Keywords
Weight loss, Speed of weight loss, Metabolic compensation, Diet therapy
Brief summary
Obesity has become a global epidemic with huge public health implications. Although clinical significant weight loss (WL) can be achieved by a combination of diet and behavioral modification, strong metabolic adaptations, with increased appetite and suppressed energy expenditure, are activated, which compromise WL maintenance and increase the risk of relapse. The aim of this project is to investigate the potential role of WL rate in modulating such responses. More specifically, the investigators want to determine if a similar WL achieved rapidly vs slowly induce the same compensatory responses to weight reduction. A secondary aim is to assess if speed of weight loss can influence motivation. A large battery of assessments will be performed before and after weight reduction including body composition, resting metabolic rate, substrate oxidation, exercise efficiency, fasting and postprandial release of several appetite-regulating hormones, subjective feelings of hunger and fullness and motivation. This project can bring large practical benefits concerning the design of weight loss programs to minimize weight relapse.
Interventions
BEHAVIORALVery-low calorie diet (VLCD)
BEHAVIORALLow calorie diet (LCD)
Sponsors
Monash University
Portuguese Research Council
Norwegian University of Science and Technology
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Adult (18-50 years old) * Obese healthy volunteers (30\<BMI\<45 kg/m2) * Weight stable on the last three months (\<2kg), not currently dieting to lose weight and with an inactive lifestyle)
Exclusion criteria
* History of endocrine/cardiovascular/pulmonary/kidney disease, anaemia, gout, milk intolerance, depression or other psychological disorders, eating disorders, drug or alcohol abuse within the last two years and current medication known to affect appetite or induce weight loss. Those with a planned surgery during the study period or participating in another research study will also not be accepted to take part in this study
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Appetite related hormones | Before the start of the study and again at week 2 and 4 (VLCD group) and 4 and 8 (LCD group). And also, on week 12 (for both groups). | Appetite-related hormones (active ghrelin, PYY, GLP-1, CCK) will be measured in fasting and every 30 minutes up to 2,5 hours |
| Body composition | Baseline, 2 and 4 weeks (VLCD group) and 4 and 8 weeks (LCD group) and 12 weeks (both groups) | Body composition measured by air displacement plethysmography |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Resting metabolic rate (RMR) | Baseline, 2 and 4 weeks (VLCD group) and 4 and 8 weeks (LCD group) and 12 weeks (both groups) | RMR measured by indirect calorimetry |
| Exercise efficiency | Baseline, 2 and 4 weeks (VLCD group) and 4 and 8 weeks (LCD group) and 12 weeks (both groups) | Exercise efficiency measured by graded exercise on a bike |
Countries
Norway
Outcome results
None listed