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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
35
Norwegian University of Science and Technology
Trondheim, Norway
Appetite related hormones
Appetite-related hormones (active ghrelin, PYY, GLP-1, CCK) will be measured in fasting and every 30 minutes up to 2,5 hours
Time frame: 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).
Body composition
Body composition measured by air displacement plethysmography
Time frame: Baseline, 2 and 4 weeks (VLCD group) and 4 and 8 weeks (LCD group) and 12 weeks (both groups)
Resting metabolic rate (RMR)
RMR measured by indirect calorimetry
Time frame: Baseline, 2 and 4 weeks (VLCD group) and 4 and 8 weeks (LCD group) and 12 weeks (both groups)
Exercise efficiency
Exercise efficiency measured by graded exercise on a bike
Time frame: Baseline, 2 and 4 weeks (VLCD group) and 4 and 8 weeks (LCD group) and 12 weeks (both groups)
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