None listed
Conditions
Brief summary
In 2015/2016, 31.6% of all New Zealanders over the age of 15 years were obese. This rising trend in obesity has been observed globally with obesity now affecting more of the world’s population than malnutrition. The World Health Organisation (WHO) estimated a prevalence of T2DM in NZ of 8.5% in 2014. Worldwide the global burden of T2DM is 422 million. Obesity is a disease of energy consumption that exceeds requirements. An individual’s daily calorie requirements are composed mainly of their resting energy expenditure (REE) and physical activity associated energy expenditure. Measurement of energy expenditure allows precise individualized calorie prescriptions to promote weight loss. However, even when a carefully administered calorie reduction is introduced with controlled physical activity, invariably less weight is lost than predicted. This has been ascribed to adaptive thermogenesis (AT) - changes in REE in response to a dietary intervention that occur in order to maintain weight at its baseline level, but are maladaptive if an individual is attempting to lose weight. AT is a result of alterations in hypothalamic neuro-hormonal circuitry resulting from obesity. Permanent changes in the regulation of body weight, energy expenditure, appetite, satiety and higher cognitive responses to food occur in the obese individual in response to weight loss. This is mediated by the central melanocortin pathway which interfaces with peripheral organs via the sympathetic and parasympathetic nervous system, leptin, adiponectin, ghrelin, insulin, glucagon and thyroid stimulating hormone, amongst others. It is not clear whether adaptive thermogenesis in response to calorie restriction requires a period of sustained dietary restriction to develop or will occur with even very brief energy restriction. An intermittent or interrupted schedule of fasting, compared with a regular schedule of daily restriction, may attenuate the development of adaptive thermogenesis in response to a calorie restricted diet. Primary Objective: To compare changes in resting energy expenditure in response to 6 weeks of intermittent or continuous calorie restriction. Secondary Objectives: To compare changes in the following parameters between treatment arms over the 6-week intervention period: fasting glucose, HbA1C & fasting lipids, weight, body composition, TSH, FT4, FT3, leptin, adiponectin, ghrelin, satiety, hunger, dietary adherence, physical activity level & diet composition.
Interventions
Brief Name:
Calorie Restriction: Arm 1 Continuous Daily Restriction (CDR)
Arm 2 Intermittent Very Low Calorie Diet (IVLCD) (see comparator group below)
The CDR arm consists of a daily calorie restriction to 78% of estimate daily requirements, this will be observed daily.
The intervention will be administered as a dietary prescription observed for duration of 6 weeks. A dietary prescription tailored to each participants estimated daily energy intake requirements will be given. Macro-nutrient
Brief Name: Calorie Restriction: Arm 1 Continuous Daily Restriction (CDR) Arm 2 Intermittent Very Low Calorie Diet (IVLCD) (see comparator group below) The CDR arm consists of a daily calorie restriction to 78% of estimate daily requirements, this will be observed daily. The intervention will be administered as a dietary prescription observed for duration of 6 weeks. A dietary prescription tailored to each participants estimated daily energy intake requirements will be given. Macro-nutrient composition will not be specified. The prescription consists of several days of set recipes. This will be based on baseline resting energy expenditure and self reported physical activity using the International Physical Activity Questionnaire (IPAQ). The recipes will be based on the participants pre-intervention food preferences and have been developed by a research dietitian with over 6 years experience. A 30 minute 1:1 counselling sessions with a member a physician on the research team will be provided at visit 1. Participants will be provided with access to calorie counting resources: http://www.caloriecount.co.nz/. This is based on the AUSNUT database from the Food Standards Authority, Australia/New Zealand. Participants will also be provided a written guide to reading nutrition labels prepared by the Food Standards Authority, Australia/New Zealand. Attempts to improve adherence will involve providing dietary counselling in relation to calories and the diet types, menus with a pre-specified diet composition and weekly telephone contact during the study. Weekly telephone calls of approximately 15 minutes duration, will be made by study by the study physicians. These calls will be performed to confirm ongoing adherence to diet, answer any questions in relation to the diet prescriptions, remind participants about upcoming assessments, to complete instruments prior to their next scheduled visits and to determine if the participants have developed any health problems since last contact. The dietary prescription will be adjusted at 3 weeks following repeat energy expenditure measurements and physical activity assessments. Food diary logs at 1 week, 3 weeks and 6 weeks will be used to assess adherence to the intervention. Participants will be asked to avoid implementing any additional weight loss measures, pharmacological or otherwise during the trial period. They will also be asked to maintain their baseline level of physical activity for the entire trial period in so far as possible. They will be asked to limit & record any alcohol intake.
Sponsors
Assoc Prof Jeremy Krebs
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
Male
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
BMI greater than or equal to 30 kg/m2.
Exclusion criteria
Recent significant weight change > 5 kg over the previous 3 months Current medical illness or medications (e.g. steroids) that may, in the view of the investigators, influence resting metabolic rate. Current Smoker Weight > 220kg, the maximum weight limit on the DEXA machine. History of any eating disorder. History of T2DM requiring treatment other than metformin or diet (1) OR poorly controlled T2DM with a HbA1C > 8.0%/64mmol/mol OR a fasting plasma glucose > 10 mmol/L(2)*.
Outcome results
None listed