None listed
Conditions
Brief summary
Newly diagnosed individuals with T2D can be managed primarily by alterations to diet and physical activity (exercise) patterns, which are used to help control blood glucose. However, uptake and adherence to any behaviour change strategy is typically challenging and therefore low. Recently, time-restricted eating (TRE) has emerged as a promising therapeutic strategy that allows meals to be consumed alongside societal norms. Rather than stipulating the composition of meals, TRE aims to reduce the ‘eating window’ to facilitate a longer overnight fast (i.e. eating between 10 am-6 pm, rather than over periods longer than 12 h). Via TRE, meal timing can be aligned with the biological circadian rhythm. Specifically, an earlier dinner may contribute to better glucose control due to the known deterioration of the hormone insulin to regulate glucose declining over the day. In those with T2D, a later breakfast may also be beneficial to avoid eating at the same time as the morning spike in fasting glucose, which is known as the ‘dawn phenomenon’ in individuals with T2D and coincides with the increased circadian concentrations of cortisol, known to stimulate the liver to release glucose into the circulation. Acutely, to our knowledge, TRE has not been measured in individuals with type 2 diabetes. TRE performed over a period of weeks has been shown to effectively reduce post-meal insulin, blood pressure, and evening appetite; if continued for up to one year it has been demonstrated to result in sustained weight loss. However, there are a lack of studies investigating the acute, one-day effects of TRE, particularly in the context of other behaviours that might influence circadian rhythm. Exercise, for example, is a potent stimulus known to influence both circadian rhythm and glucose control. For individuals with T2D, just 10 minutes of walking in each of the 1 hour post-prandial period across a day is enough to improve blood glucose control. However, it is unknown whether strategically-timed exercise combined with TRE would result in an additive benefit to glucose control over the course of a day. In addition, it is unknown whether the benefits of exercise for glucose control would mitigate the detrimental effect of an extended feeding window on glucose control.
Interventions
In a randomised, cross-over design (with a minimum of 3-days washout period between each), participants will complete four trial conditions (including one control condition) where they attend the laboratory between 7 am and 10 pm to have serial blood samples taken and subsequently measured and all meals provided through the following conditions:
1) A normal "control" eating condition (eating all meals within 12 h; at 8 am, 2 pm and 8 pm);
2) Exercise breaks (3 x 15 min walking bouts on a treadmi
In a randomised, cross-over design (with a minimum of 3-days washout period between each), participants will complete four trial conditions (including one control condition) where they attend the laboratory between 7 am and 10 pm to have serial blood samples taken and subsequently measured and all meals provided through the following conditions: 1) A normal "control" eating condition (eating all meals within 12 h; at 8 am, 2 pm and 8 pm); 2) Exercise breaks (3 x 15 min walking bouts on a treadmill at 60% VO2peak, each in the 45 min - 1 hour post meal periods (i.e. 15 min exercise after each meal) with a control eating condition (eating all meals within 12 h, at 8 am, 2 pm and 8 pm); 3) Time-restricted eating condition (eating all meals within 8 h; at 10 am, 2 pm and 6 pm); 4) Exercise breaks (3 x 15 min walking bouts on a treadmill at 60% VO2peak, each in the 45 min - 1 hour post meal periods (i.e. 15 min exercise after each meal) with time-restricted eating (eating all meals within 8 h, at 10 am, 2 pm and 6 pm). In all conditions, except for exercise times, participants will remain seated and will be provided the opportunity to move during standardised toilet breaks throughout the day and may bring books or computers etc to entertain themselves between measures in all conditions. All meals will be provided at standardised times (#1/2: 8 am, 2 pm and 8 pm; #3/4: 10 am, 2 pm and 6 pm) and each meal will be of similar composition to typical macronutrient intake of ~50% carbohydrate, ~30% fat and ~20% protein. All meals will be designed by an accredited practicing dietitian and will be of the same foods for all participants, but calculated for energy intake relative to each individuals total daily energy requirements (as determined by resting metabolic rate multiplied by an activity factor of 1.4). No snacks will be provided but water can be consumed ad libitum in the first trial and will be repeated in the subsequent trials.
Sponsors
Dr Evelyn Parr
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
35 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
• Aged 35 to 65 years old • Diagnosed (by a GP/endocrinologist) with type 2 diabetes mellitus (T2D), with an HbA1c between 6.5% - 9.9%, and either diet-controlled or taking a maximum of two oral antihyperglycemic agents (excluding sulphonylureas, insulin and GLP-1 agonists) • Body mass index (BMI) between 25 - 45 kg/m2 (but total mass not >200 kg due to DXA measures)
Exclusion criteria
• Meeting current guidelines for physical activity (i.e. greater than 150 minutes of moderate physical activity per week for greater than 4 weeks); • Taking glucose lowering medications which recommend not fasting (i.e. sulphonylureas, or insulin) or requiring injecting (i.e. GLP-1 agonists); • Currently following a strict diet (i.e. vegan, coeliac/gluten free, ketogenic); • Participate in regular fasting (defined as fasting for equal to or greater than 16 h per day or having completed twelve 24-h fasts within the past year); • Participating in shift work (i.e. greater than 3 h between 10 pm and 5 am for 1 day per week (more than 50 days per year)) • Not weight stable (greater than 5 kg change over last 3 months); • On prescribed medications required to be taken with food in the early morning or late evening or taking other prescribed medications for greater than 3 months; • Current smoker (tobacco, nicotine or marijuana) or within 3 months of quitting; • Women who are pregnant, breastfeeding (within 24 wk); • Psychopharmacological treatment that has not been stable for more than 3 months; • Medications known to promote weight gain, weight loss or interact with glucose metabolism (i.e. corticosteroids); • Diagnosed gastrointestinal conditions, surgery (i.e. bariatric) or impaired nutrient absorption; • Known physical activity contraindications; • Major illness/physical problems (acute or chronic) that may limit the ability to perform walking on a treadmill for 15 minutes; • Previous hospitalisation/treatment for cardiac event.
Outcome results
None listed