Eight weeks of intermittent fasting versus calorie restriction does not alter eating behaviors, mood, sleep quality, quality of life and cognitive performance in women with overweight

Human trials that compare intermittent fasting (IF) to calorie restriction (CR) with psychological, behavioral and cognition outcomes are limited. We hypothesized that there would be no difference between CR and IF on perceived eating behaviors, mood, sleep quality, quality of life (QOL) and cognition in women with overweight and obesity. In this prespecified secondary analysis of an open-label, single center, parallel assignment, randomized controlled trial, healthy women with overweight or obesity (N = 46, mean [SD] age 50 [9] years, BMI 32.9 [4.4] kg/m2), without a diagnosed eating disorder and who were randomized into 2 weight loss groups (prescribed 70% of calculated energy requirements as IF or CR) were included. Measurements were assessed in both IF and CR groups following a 12-hour overnight fast during baseline and week 8 and additionally following a 24-hour fast in the IF group only at week 8. We observed that IF produced greater weight and body fat loss than CR (P .05). IF may be a viable alternative to CR for weight loss, in the short-term, without adversely impacting eating behaviors, mood, sleep quality, QOL or cognition in healthy women with overweight or obesity. However, larger and long term trials are required.Xiao TongTeong, Amy T.Hutchison, Bo Liu, Gary A.Wittert, Kylie Lange, Siobhan Banks, Leonie K.Heilbron

An update to the study protocol for a randomized controlled trial comparing daily calorie restriction versus intermittent fasting to improve glycaemia in individuals at increased risk of developing type 2 diabetes

Xiao Tong Teong, Kai Liu, Amy T. Hutchison, Bo Liu, Christine Feinle-Bisset, Gary A. Wittert ... et al

Preoperative dietitian-led Very Low Calorie Diet (VLCD) Clinic for adults living with obesity undergoing gynaecology, laparoscopic cholecystectomy, and hernia repair procedures: a pilot parallel Randomised Controlled Trial

Obesity can increase the risk of postoperative complications. Despite increased demand for patients living with obesity to lose weight prior to common surgical procedures, the impact of intentional weight loss on surgical outcomes is largely unknown. We aimed to conduct a pilot study to assess the feasibility of a full-scale randomised controlled trial (RCT) to examine the effect of preoperative dietitian-led Very Low Calorie Diet (VLCD) Clinic on surgical outcomes in gynaecology and general surgeries. Between August 2021 and January 2023, a convenience sample of adults living with obesity (BMI ≥ 30 kg/m2) awaiting gynaecology, laparoscopic cholecystectomy and ventral hernia repair procedures were randomised to dietitian-led VLCD (800–1000 kcal using meal replacements and allowed foods), or control (no dietary intervention), 2–12 weeks preoperatively. Primary outcome was feasibility (recruitment, adherence, safety, attendance, acceptability and quality of life (QoL)). Secondary outcomes were anthropometry and 30-d postoperative outcomes. Outcomes were analysed as intention-to-treat. Fifty-one participants were recruited (n 23 VLCD, n 28 control), mean 48 (SD 13) years, 86 % female, and mean BMI 35·8 (SD 4·6) kg/m2. Recruitment was disrupted by COVID-19, but other thresholds for feasibility were met for VLCD group: high adherence without unfavourable body composition change, high acceptability, improved pre/post QoL (22·1 ± 15 points, 0·05). The RCT study design was deemed feasible in a public hospital setting. The dietitian-led VLCD resulted in significant weight loss and waist circumference reduction compared with a control group, without unfavourable body composition change and improved QoL.</p

Rationale and protocol for a randomized controlled trial comparing daily calorie restriction versus intermittent fasting to improve glycaemia in individuals at increased risk of developing type 2 diabetes

BACKGROUND: Intermittent fasting (IF) is proposed as a viable alternative to moderate calorie restriction (CR) for weight loss and metabolic health, but few long term randomized trials have been conducted. This protocol paper describes the rationale and detailed protocol for DIRECT study (Daily versus Intermittent Restriction of Energy: Controlled Trial to Reduce Diabetes Risk), comparing long term effectiveness of IF versus CR on metabolic health in individuals who are at increased risk of developing type 2 diabetes. METHODS: Anticipated 260 non-diabetic men and women aged 35-75 years, BMI 25-50 kg/m2 with score ≥12 on the Australian Diabetes Risk (AUSDRISK) calculator will be recruited into this open-label, multi-arm, parallel group sequential randomized controlled trial. Participants will be randomized to one of three groups for 18 months: IF (30% of energy needs on fast days), CR (70% of energy needs daily), or standard care (SC) group. All participants will visit the clinic fortnightly for weight assessments during active intervention phase (6 months), followed by a 12-month follow-up phase. IF and CR groups will receive further diet counselling by dietitian. Two primary outcomes are the changes in glycated haemoglobin (HbA1c) and postprandial glucose area under the curve (AUC) at week 24 post-randomization. Secondary outcomes include changes in weight, body composition via dual-energy X-ray absorptiometry, gastro-intestinal hormones, cardiovascular risk factors, and dietary record by a smartphone-based application. DISCUSSION: This study will provide substantial evidence as to whether IF is an effective nutrition intervention for glycaemic control in a population at risk of developing type 2 diabetes.Xiao Tong Teong, Kai Liu, Amy T. Hutchison, Bo Liu, Christine Feinle-Bisset, Gary A.Wittert ... et al

Impact of a dietitian-led very low calorie diet clinic on perioperative risk for patients with obesity awaiting elective, non-bariatric surgery: A retrospective cohort study

Background: Despite a lack of evidence that intentional weight loss reduces the risk of postoperative complications, adults with obesity are commonly asked to lose weight before elective surgery. We hypothesized that patients undertaking dietitian-led preoperative, very low calorie diet treatment could reduce perioperative surgery risks, as per validated risk scoring systems. The purpose of this study was to measure the impact of a dietitian-led preoperative very low calorie diet clinic on the American Society of Anesthesiologists physical status scores and National Surgical Quality Improvement Program Surgical Risk Calculator scores for patients with obesity awaiting non-bariatric elective surgery. Methods: This retrospective cohort study included patients referred to the preoperative dietitian-led very low calorie diet clinic before elective surgical procedures over a 2-year-9-month period. The dietitian prescribed individualized, very low calorie diet-based treatment. Primary outcomes were changes in the American Society of Anesthesiologists and Surgical Risk Calculator scores from pretreatment until surgery. Results: A total of 141 eligible participants (48 ± 13.4 years, 76% women, body mass index 41.7 ± 6.3 kg/m2) demonstrated clinically significant weight loss (mean 7.1 ± 6.1kg, 5.2% body weight, P < .001). Median treatment duration was 13 weeks (interquartile range 6.2–19.2 weeks). Five participants (3.5%) avoided surgery due to weight loss-related improvements in their condition. American Society of Anesthesiologists scores improved for 16% (n = 22/141) of participants. Overall, the median surgical risk calculator estimated risk of ‘serious’ and ‘any’ postoperative complication reduced from 4.8% to 3.9% (P < .001) and 6% to 5.1% (P < .001), respectively. Reduction in all Surgical Risk Calculator scores occurred, including surgical site infection, re-admission, and cardiac events (P < .05). Conclusion: The dietitian-led preoperative, very low calorie diet clinic improved American Society of Anesthesiologists and Surgical Risk Calculator scores for non-bariatric elective surgery patients with obesity. Randomized controlled trials comparing this approach with a control group are warranted</p

Eating architecture in adults at increased risk of type 2 diabetes: associations with body fat and glycaemic control

First published online 5 August 2021Eating architecture is a term that describes meal frequency, meal timing, and meal size and the daily variation in each of these. The aim of this study was to determine the relationship between components of eating architecture on body fat and markers of glycaemic control in healthy adults at increased risk of type 2 diabetes (T2DM). Participants (N=73, 39 males, age 58.8 [8.1] years, BMI 33.4 [4.4] kg/m²) recorded food intake and wore accelerometers and continuous glucose monitors (CGM) for 7-14 days under free-living conditions. Body fat and glycated haemoglobin (HbA1c) were also measured. The mean and day-to-day variation (calculated as the standard deviation during the monitoring period) of each component of eating architecture were calculated. Multivariable linear regression models were constructed for three separate outcome variables (body fat mass, mean CGM glucose, and HbA1c) for each component of eating architecture before and after adjustment for confounders. Higher variability in the time of first meal consumption was associated with increased body fat mass after adjusting for confounders (β=0.227, 95% CI: 0.019, 0.434, p=0.033). Increased variability in the time lag from waking to first meal consumption was also positively associated with increased HbA1c after adjustment (β=0.285, 95%CI: 0.040, 0.530, p=0.023). Low day-to-day variability in first meal consumption was associated with lower body fat and improved glucose control in adults at increased risk of T2DM. Routine consumption of meals may optimise temporal regulation to anticipate and respond appropriately to a glucose challenge.Lijun Zhao, Xiao Tong Teong, Kai Liu, Bo Liu, Yohannes Adama Melaku, Andrew Vincent, Emily Manoogian, Satchidananda Panda, Gary A. Wittert, Amy Hutchison, and Leonie K. Heilbron