None listed
Conditions
Brief summary
Presently there is a large push in the non-scientific nutrition-diet community towards a high-fat diet for improving any disease state, with very little scientific evidence. In fact, research in animals (rats) has shown the negative effects of the high-fat, low carbohydrate diet to glucose regulation and weight management. In line with this research, much of the circadian rhythm and metabolomics literature published to date has been using animal models and no human data exists in this area. Establishing the circadian profile in a healthy middle aged population will act to inform future diet and exercise training studies. Currently, there are no dietary studies of circadian clock genes in humans and with increasing rates of type 2 diabetes and obesity, dietary alterations are common within today’s society that the consequences of such changes are not well understood.
Interventions
The study will employ two conditions, administered in a randomized design, for each participant. One condition will involve participants being on a high fat, low carbohydrate diet (Condition A) for five days. The other condition will involve participants being on a high carbohydrate, low fat diet (Condition B) for five days. Dietary interventions will be separated by a one week washout and all food for each intervention period will be provided prior to the consumption period. Skeletal muscle bio
The study will employ two conditions, administered in a randomized design, for each participant. One condition will involve participants being on a high fat, low carbohydrate diet (Condition A) for five days. The other condition will involve participants being on a high carbohydrate, low fat diet (Condition B) for five days. Dietary interventions will be separated by a one week washout and all food for each intervention period will be provided prior to the consumption period. Skeletal muscle biopsies will be collected in the morning (8 am) and at night (8 pm) on day 5 of each diet regime, as well as at the end of a 7 day food diary period of each participants typical dietary intake (to establish individual baselines) prior to each dietary intervention - i.e. eight biopsies per person in total over the trials. To achieve this, participants will complete 8 x 2.5 h visits to the laboratory. During each morning visit, DXA (for body composition), resting metabolic rate (RMR) and a blood sample will be measured. Following from these a single muscle biopsy will be obtained. Participants will then be free to leave the laboratory and will return in the evening. For each evening visit, a blood sample and a muscle biopsy will be obtained. An initial RMR and DXA measure, prior to each baseline period of 7 day food record, will be used to calculate participants energy requirements for the provided dietary periods. Throughout the two x 7 day baseline measurement periods and each of the two x 5 day periods of dietary modification, participants will wear activity and glucose monitors and record their dietary intake. Condition A: Dietary intake will be a high fat diet, with a composition of 65% energy from fat, 15% energy from carbohydrate and 20% energy from protein Condition B: Dietary intake will be a high carbohydrate diet, with a composition of 65% energy from carbohydrate, 15% energy from fat and 20% energy from protein
Sponsors
Professor John Hawley
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
Male
Age
30 Years to 45 Years
Healthy volunteers
No
Inclusion criteria
Overweight or obese as defined by a BMI between 27-32.5 kg/m2 Sedentary (for both occupation and recreational time - no more than 150 minutes of regular physical activity during a week, typical television watching time >3 h per day).
Exclusion criteria
Major or chronic illness that impairs mobility or eating/digestion/metabolism (i.e. type 2 diabetes, cancer, gastrointestinal disorders); previous bariatric surgery; shift workers; smokers; individuals with strict dietary intake regimes (i.e. vegan, avoidance of principal study foods); individuals who do not regularly consume a breakfast meal; individuals who do not have a regular dietary pattern of meals (i.e. breakfast, lunch, dinner); individuals who are currently restricting their dietary intake (i.e. actively trying to diet and lose weight); individuals who have not been weight stable for the last 3 months.
Outcome results
None listed