None listed
Conditions
Brief summary
Energy distribution (i.e., timing of calories ingested) and sedentary behaviours are important factors for glucose metabolism. Most Australians currently consume the majority of their energy in the evening, with dinner and an evening snack contributing up to 45% of the total daily energy intake. The pattern of increased energy intake in the evenings has previously been associated with an increased risk of obesity while partitioning calories normally consumed from dinner to earlier in the day (i.e., breakfast) has been associated with better appetite control and lower blood glucose and blood insulin levels-two important risk factors for type 2 diabetes. In addition, the extent to which sedentary behaviours (particularly prolonged periods of uninterrupted sitting) may contribute to the negative effects back-ending current feeding patterns is not well understood. However, earlier consumption of energy (i.e. larger breakfasts) and may be more beneficial to glucose metabolism in the context of prolonged periods of sitting. Similarly, frequent active breaks in the form of simple resistance exercises may also improve glucose metabolism when performed during extended periods of sedentary behaviour. Consequently, the aim of the present study is to examine how manipulations to the distribution of energy throughout the day influences blood glucose and insulin metabolism, and appetite control, during periods of prolonged sitting compared to breaking-up sitting time with intermittent simple resistance exercise in overweight/obese men and women. It is hypothesised that a day of prolonged uninterrupted sitting may potentially accentuate the effects elicited by a high caloric end-of-day feeding pattern compared to prolonged sitting interrupted by simple resistance exercises in individuals with pre-diabetes and Type 2 diabetes.
Interventions
Participants will complete 4 x 36 h periods of activity (using ActivPal and ActiGraph monitors) and glucose (using continuous blood glucose monitors) monitoring.
Participants will spend one day at the laboratory (between 7.30 am and 7 pm) during each of the 36 h periods.
Prior to the trial day, participants will receive a standardised meal to take home and consume for their last meal of the day, have finger prick blood samples taken, have a continuous blood glucose monitor (CGM) inserted subcut
Participants will complete 4 x 36 h periods of activity (using ActivPal and ActiGraph monitors) and glucose (using continuous blood glucose monitors) monitoring. Participants will spend one day at the laboratory (between 7.30 am and 7 pm) during each of the 36 h periods. Prior to the trial day, participants will receive a standardised meal to take home and consume for their last meal of the day, have finger prick blood samples taken, have a continuous blood glucose monitor (CGM) inserted subcutaneously on their lower back and have an ActivPal activity monitor adhered to their thigh. This appointment will take ~1 h prior to trial day. On a trial day, participants will get a taxi (costs covered by the study) to the laboratory. An indwelling cannula will be inserted into an anticubital vein of the forearm, and the study involves having serial blood measures and answering appetite questionnaires for the duration of a day (8 am to 7 pm) whilst remaining seated. Meals will be provided for breakfast (9am), lunch (1 pm) and dinner (5 pm) to consume at the laboratory. At the end of the trial day, participants will be taxied home, and they will wear the CGM and the Activpal and ActiGraph until 8 am the next morning. Trials will be separated by at least a 7 day period. Condition A: Energy intake is distributed with 20% of energy at breakfast, 30% of energy at lunch and 50% of energy at dinner whilst prolonged sitting. Condition B: Energy intake is distributed with 50% of energy at breakfast, 30% of energy at lunch and 20% of energy at dinner whilst prolonged sitting. Condition C: Energy intake is distributed with 20% of energy at breakfast, 30% of energy at lunch and 50% of energy at dinner with frequent active breaks (2 min every 30 min) throughout the prolonged sitting period. Condition D: Energy intake is distributed with 50% of energy at breakfast, 30% of energy at lunch and 20% of energy at dinner with frequent active breaks (2 min every 30 min) throughout the prolonged sitting period. For both dietary interventions the macronutrient distribution will be the same (i.e. 50% energy from carbohydrate, 20% energy from protein and 30% energy from fat).. Participants will complete food and activity diaries across the period encompassing the day prior to and the day after each trial day to ensure adherence. Whilst in the laboratory, participants will be monitored by the research staff.
Sponsors
Professor John Hawley
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
40 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
Presenting as pre-diabetic - [by having a fasting blood glucose greater than 5.9 mmol/L and/or a 2 hour oral glucose tolerance test blood glucose between 7.8 mmol/L and 11.0 mmol/L] OR as Type 2 diabetic - [by having a fasting blood glucose greater than 7.2 mmol/L and/or a 2 hour oral glucose tolerance test blood glucose greater than 11.0 mmol/L. Being overweight or obese - [body mass index (BMI) greater than 25 kg/m2 and less than 45 kg/m2.
Exclusion criteria
Participants will be excluded on the basis of: pregnancy; use of carbohydrate or lipid-lowering medication if it has been commenced within 3 months; bariatric surgery (gastric bypass or banding); employment in a non-sedentary occupation; currently watching less than 3 hours of television or computer use per day; regularly engaged in moderate-intensity exercise for greater than 150 min/week for more than 3 months; major illness/injury (acute or chronic), current smoker or use of nicotine replacement therapy; or physical or major illness/physical problems (acute or chronic) that may limit their ability to participate in the intervention.
Outcome results
None listed