An intermittent energy restricted (IER) diet may modify cardio-metabolic disease risk factors compared to an energy-matched continuous energy restricted (CER) diet. A randomised controlled parallel design trial will determine the impact of a short-term IER diet (2 consecutive days of very low calorie diet (VLCD), 5 days moderate energy restriction each week for a 4 week period), compared to a CER diet, on insulin sensitivity in healthy (disease-free) subjects with central obesity.
Prediabetes rates in England have showed a marked increase, more than tripling between 2003 and 2011. It is characterised by an impaired fasting glucose or impaired glucose tolerance that increases the risk of progression to type 2 diabetes (T2D). It has been estimated that approximately 90% of T2D is attributed to excess weight. Central obesity is a primary driver of increased cardiometabolic risk due to its lipotoxicity effects, promoting a proinflammatory state that facilitates insulin resistance and beta cell dysfunction. A high waist circumference measurement, indicative of central obesity, is associated with increased risk of cardiovascular diseases and T2D, and is a stronger predictor of T2D than BMI. BMI has limitations as an indicator of adiposity since it doesn't distinguish lean from fat mass, and does not indicate body fat distribution. Conventionally, continuous energy restriction (CER) diets have been used for weight loss, which consist of a constant daily energy deficit relative to total energy expenditure. The impact on weight loss and health of an intermittent energy restriction (IER) approach has only rarely been investigated (although the "5:2 diet" has been popularised in lifestyle books aimed at the general public). An IER diet consists of a predefined period of time severely restricting energy intake, alternated with a period of greater energy intake. This approach was shown to confer metabolic benefits in overweight and obese women at risk of breast cancer with baseline BMI of 2445 (Harvie et al., 2013; Harvie et al., 2011). Rationale: An IER diet using meal replacements (VLCD foodpacks used as total dietary replacements for 2 consecutive days each week, and a food-based energy-restricted diet for the other 5 days of the week) may modify cardio-metabolic disease risk factors compared to an energy-matched CER diet. Research question: In centrally obese subjects, assessed by a high waist circumference measurement, does adherence to an IER diet have enhanced cardio-metabolic benefits compared to a CER diet? Hypothesis: Increases in insulin sensitivity following a 4 week dietary intervention with an IER weight loss programme will be greater compared to a standard CER programme. Objectives: 1. A randomised controlled parallel design trial will determine the impact of a short-term IER diet compared to a CER diet on primary outcome variables (insulin sensitivity) in healthy subjects with a high waist circumference. 2. To assess the impact of an IER diet on secondary outcome variables, including body composition, heart rate variability (HRV, a measure of cardiac autonomic function, including parasympathetic and sympathetic activity), blood pressure, vascular function, other markers of insulin resistance, inflammation/adipokines, plasma lipid profile, plasma norepinephrine, ketosis, the gut microbiome and cognitive function in healthy subjects with a high waist circumference.
Dietary advice to follow 5:2 diet supported by physical activity advice and motivational group support sessions
Dietary advice to follow daily energy restricted diet supported by physical activity advice and motivational group support sessions
Diabetes & Nutritional Sciences Division, King's College London, Franklin-Wilkins Buiding, 150 Stamford St.
London, England, United Kingdom
Revised QUICKI (RQUICKI)
Marker of insulin sensitivity
Time frame: Baseline
RQUICKI
Marker of insulin sensitivity
Time frame: day 29
RQUICKI
Marker of insulin sensitivity
Time frame: day 31
Plasma glucose concentration
Fasting
Time frame: Baseline
Plasma glucose concentration
Fasting
Time frame: day 29
Plasma glucose concentration
Fasting
Time frame: day 31
Plasma insulin concentration
Fasting
Time frame: Baseline
Plasma insulin concentration
Fasting
Time frame: day 29
Plasma insulin concentration
Fasting
Time frame: day 31
Plasma non-esterified fatty acid concentration
Fasting
Time frame: Baseline
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
42
Plasma non-esterified fatty acid concentration
Fasting
Time frame: day 29
Plasma non-esterified fatty acid concentration
Fasting
Time frame: day 31
Plasma total cholesterol concentration
Fasting
Time frame: Baseline
Plasma total cholesterol concentration
Fasting
Time frame: day 29
Plasma total cholesterol concentration
Fasting
Time frame: day 31
Plasma low density lipoprotein (LDL) cholesterol concentration
Fasting
Time frame: Baseline
Plasma LDL cholesterol concentration
Fasting
Time frame: day 29
Plasma LDL cholesterol concentration
Fasting
Time frame: day 31
Plasma high density lipoprotein (HDL) cholesterol concentration
Fasting
Time frame: Baseline
Plasma HDL cholesterol concentration
Fasting
Time frame: day 29
Plasma HDL cholesterol concentration
Fasting
Time frame: day 31
Plasma triglyceride concentration
Fasting
Time frame: Baseline
Plasma triglyceride concentration
Fasting
Time frame: day 29
Plasma triglyceride concentration
Fasting
Time frame: day 31
Plasma total cholesterol:HDL cholesterol ratio
Fasting
Time frame: Baseline
Plasma total cholesterol:HDL cholesterol ratio
Fasting
Time frame: day 29
Plasma total cholesterol:HDL cholesterol ratio
Fasting
Time frame: day 31
Homeostasis model assessment estimated insulin resistance (HOMA-IR)
Fasting (calculated from insulin and glucose)
Time frame: Baseline
Homeostasis model assessment estimated insulin resistance (HOMA-IR)
Fasting (calculated from insulin and glucose)
Time frame: day 29
Homeostasis model assessment estimated insulin resistance (HOMA-IR)
Fasting (calculated from insulin and glucose)
Time frame: day 31
Plasma adiponectin concentration
Fasting
Time frame: Baseline
Plasma adiponectin concentration
Fasting
Time frame: day 29
Plasma adiponectin concentration
Fasting
Time frame: day 31
Plasma leptin concentration
Fasting
Time frame: Baseline
Plasma leptin concentration
Fasting
Time frame: day 29
Plasma leptin concentration
Fasting
Time frame: day 31
Plasma interleukin-6 concentration
Fasting
Time frame: Baseline
Plasma interleukin-6 concentration
Fasting
Time frame: day 29
Plasma interleukin-6 concentration
Fasting
Time frame: day 31
Plasma beta-hydroxybutyrate concentration
Fasting
Time frame: Baseline
Plasma beta-hydroxybutyrate concentration
Fasting
Time frame: day 29
Plasma beta-hydroxybutyrate concentration
Fasting
Time frame: day 31
Plasma norepinephrine concentration
Fasting
Time frame: Baseline
Plasma norepinephrine concentration
Fasting
Time frame: day 29
Plasma norepinephrine concentration
Fasting
Time frame: day 31
Plasma soluble alpha-klotho concentration
Fasting
Time frame: Baseline
Plasma soluble alpha-klotho concentration
Fasting
Time frame: day 29
Plasma soluble alpha-klotho concentration
Fasting
Time frame: day 31
Body weight
Time frame: Baseline
Body weight
Time frame: day 29
Body weight
Time frame: day 31
Body mass index (BMI)
Time frame: Baseline
BMI
Time frame: day 29
BMI
Time frame: day 31
Waist circumference
Time frame: Baseline
Waist circumference
Time frame: day 29
Waist circumference
Time frame: day 31
Hip circumference
Time frame: Baseline
Hip circumference
Time frame: day 29
Hip circumference
Time frame: day 31
Percentage body fat
Time frame: Baseline
Percentage body fat
Time frame: day 29
Percentage body fat
Time frame: day 31
Percentage lean body mass
Time frame: Baseline
Percentage lean body mass
Time frame: day 29
Percentage lean body mass
Time frame: day 31
Heart rate variability (resting)
supine
Time frame: Baseline
Heart rate variability (resting)
supine
Time frame: day 29
Heart rate variability (resting)
supine
Time frame: day 31
Heart rate variability (ambulatory)
Time frame: 24 h recording at baseline
Heart rate variability (ambulatory)
Time frame: 24 h recording on day 29
Heart rate variability (ambulatory)
Time frame: 24 h recording on day 31
Heart rate variability (sleep-time)
Time frame: Baseline
Heart rate variability (sleep-time)
Time frame: day 29
Heart rate variability (sleep-time)
Time frame: day 31
Heart rate variability (during mental stress)
Time frame: Baseline
Heart rate variability (during mental stress)
Time frame: day 29
Heart rate variability (during mental stress)
Time frame: day 31
Ambulatory blood pressure 24 h
Time frame: 24 h analysis at baseline
Ambulatory blood pressure daytime
Time frame: Daytime analysis at baseline
Ambulatory blood pressure night-time
Time frame: Night-time analysis at baseline
Ambulatory blood pressure 24 h
Time frame: 24 h analysis on day 29
Ambulatory blood pressure daytime
Time frame: daytime analysis on day 29
Ambulatory blood pressure night-time
Time frame: night-time analysis on day 29
Ambulatory blood pressure 24 h
24 h
Time frame: 24 h analysis on day 31
Ambulatory blood pressure daytime
day time
Time frame: Daytime analysis on day 31
Ambulatory blood pressure night-time
night-time
Time frame: Night-time analysis on day 31
Digital volume pulse - stiffness index (SI)
Stiffness index
Time frame: Baseline
Digital volume pulse - SI
Stiffness index
Time frame: day 29
Digital volume pulse - SI
Stiffness index
Time frame: day 31
Digital volume pulse - reflection index (RI)
reflection index
Time frame: Baseline
Digital volume pulse - RI
reflection index
Time frame: day 29
Digital volume pulse - RI
reflection index
Time frame: day 31
Mnemonic Similarity Test
Time frame: Baseline
Mnemonic Similarity Test
Time frame: day 29
Mnemonic Similarity Test
Time frame: day 31
Power of food scale
questionnaire
Time frame: Baseline
Power of food scale
questionnaire
Time frame: day 29
Power of food scale
questionnaire
Time frame: day 31
COPE (not an acronym)
questionnaire
Time frame: Baseline
COPE
questionnaire
Time frame: day 29
COPE
questionnaire
Time frame: day 31