Intermittent fasting, Paleolithic, or Mediterranean diets in the real world: exploratory secondary analyses of a weight-loss trial that included choice of diet and exercise.
The American journal of clinical nutrition. 2020;(3):503-514
BACKGROUND Intermittent fasting (IF) and Paleolithic (Paleo) diets produce weight loss in controlled trials, but minimal evidence exists regarding long-term efficacy under free-living conditions without intense dietetic support. OBJECTIVES This exploratory, observational analysis examined adherence, dietary intake, weight loss, and metabolic outcomes in overweight adults who could choose to follow Mediterranean, IF, or Paleo diets, and standard exercise or high-intensity interval training (HIIT) programs, as part of a 12-mo randomized controlled trial investigating how different monitoring strategies influenced weight loss (control, daily self-weighing, hunger training, diet/exercise app, brief support). METHODS A total of 250 overweight [BMI (in kg/m2) ≥27] healthy adults attended an individualized dietary education session (30 min) relevant to their self-selected diet. Dietary intake (3-d weighed diet records), weight, body composition, blood pressure, physical activity (0, 6, and 12 mo), and blood indexes (0 and 12 mo) were assessed. Mean (95% CI) changes from baseline were estimated using regression models. No correction was made for multiple tests. RESULTS Although 54.4% chose IF, 27.2% Mediterranean, and 18.4% Paleo diets originally, only 54% (IF), 57% (Mediterranean), and 35% (Paleo) participants were still following their chosen diet at 12 mo (self-reported). At 12 mo, weight loss was -4.0 kg (95% CI: -5.1, -2.8 kg) in IF, -2.8 kg (-4.4, -1.2 kg) in Mediterranean, and -1.8 kg (-4.0, 0.5 kg) in Paleo participants. Sensitivity analyses showed that, due to substantial dropout, these may be overestimated by ≤1.2 kg, whereas diet adherence increased mean weight loss by 1.1, 1.8, and 0.3 kg, respectively. Reduced systolic blood pressure was observed with IF (-4.9 mm Hg; -7.2, -2.6 mm Hg) and Mediterranean (-5.9 mm Hg; -9.0, -2.7 mm Hg) diets, and reduced glycated hemoglobin with the Mediterranean diet (-0.8 mmol/mol; -1.2, -0.4 mmol/mol). However, the between-group differences in most outcomes were not significant and these comparisons may be confounded due to the nonrandomized design. CONCLUSIONS Small differences in metabolic outcomes were apparent in participants following self-selected diets without intensive ongoing dietary support, even though dietary adherence declined rapidly. However, results should be interpreted with caution given the exploratory nature of analyses. This trial was registered with the Australian New Zealand Clinical Trials Registry as ACTRN12615000010594 at https://www.anzctr.org.au.
The Effectiveness of Intermittent Fasting to Reduce Body Mass Index and Glucose Metabolism: A Systematic Review and Meta-Analysis.
Journal of clinical medicine. 2019;8(10)
Plain language summary
Calorie restriction (CR) is known to reduce body weight and to improve various cardiovascular risk factors. Due to the many difficulties in sustaining daily CR, intermittent fasting (IF) has been proposed as an alternative strategy for achieving and maintaining weight reduction. The aim of this study was to investigate the effectiveness of IF on weight loss and glucose metabolism by analysing the effect size of previous studies among the general population without diabetes mellitus. A total of 12 studies were included in this study. The total number of participants was 545 (261 in the intervention group and 284 in the control group). Study analysis indicates an improvement in glycaemic control and insulin resistance through IF diet as compared with a non-fasting control group. Lean mass was relatively conserved in the IF diet group however, no significant weight reduction was identified. Authors conclude that IF diet may improve fat distribution in the general population without chronic metabolic disease.
undefined: The effects of an intermittent fasting diet (IFD) in the general population are still controversial. In this study, we aimed to systematically evaluate the effectiveness of an IFD to reduce body mass index and glucose metabolism in the general population without diabetes mellitus. Cochrane, PubMed, and Embase databases were searched to identify randomized controlled trials and controlled clinical trials that compared an IFD with a regular diet or a continuous calorie restriction diet. The effectiveness of an IFD was estimated by the weighted mean difference (WMD) for several variables associated with glucometabolic parameters including body mass index (BMI) and fasting glucose. The pooled mean differences of outcomes were calculated using a random effects model. From 2814 studies identified through a literature search, we finally selected 12 articles (545 participants). Compared with a control diet, an IFD was associated with a significant decline in BMI (WMD, -0.75 kg/m ; 95% CI, -1.44 to -0.06), fasting glucose level (WMD, -4.16 mg/dL; 95% CI, -6.92 to -1.40), and homeostatic model assessment of insulin resistance (WMD, -0.54; 95% CI, -1.05 to -0.03). Fat mass (WMD, -0.98 kg; 95% CI, -2.32 to 0.36) tended to decrease in the IFD group with a significant increase in adiponectin (WMD, 1008.9 ng/mL; 95% CI, 140.5 to 1877.3) and a decrease in leptin (WMD, -0.51 ng/mL; 95% CI, -0.77 to -0.24) levels. An IFD may provide a significant metabolic benefit by improving glycemic control, insulin resistance, and adipokine concentration with a reduction of BMI in adults.
Lifestyle Medicine for Clinicians
This is a digital modular course based on Inspired Medics signature conference "The Future of Healthcare is Lifestyle Medicine."
Effect of intermittent compared to continuous energy restriction on weight loss and weight maintenance after 12 months in healthy overweight or obese adults.
International journal of obesity (2005). 2019;(10):2028-2036
BACKGROUND AND OBJECTIVE Intermittent energy restriction (IER) is an alternative to continuous energy restriction (CER) for weight loss. There are few long-term trials comparing efficacy of these methods. The objective was to compare the effects of CER to two forms of IER; a week-on-week-off energy restriction and a 5:2 program, during which participants restricted their energy intake severely for 2 days and ate as usual for 5 days, on weight loss, body composition, blood lipids, and glucose. SUBJECTS AND METHODS A one-year randomized parallel trial was conducted at the University of South Australia, Adelaide, Australia. Participants were 332 overweight and obese adults, ages 18-72 years, who were randomized to 1 of 3 groups: CER (4200 kJ/day for women and 5040 kJ/day for men), week-on-week-off energy restriction (alternating between the same energy restriction as the continuous group for one week and one week of habitual diet), or 5:2 (2100 kJ/day on modified fast days each week for women and 2520 kJ/day for men, the 2 days of energy restriction could be consecutive or non-consecutive). Primary outcome was weight loss, and secondary outcomes were changes in body composition, blood lipids, and glucose. RESULTS For the 146 individuals who completed the study (124 female, 22 male, mean BMI 33 kg/m2) mean weight loss, and body fat loss at 12 months was similar in the three intervention groups, -6.6 kg for CER, -5.1 kg for the week-on, week-off and -5.0 kg for 5:2 (p = 0.2 time by diet). Discontinuation rates were not different (p = 0.4). HDL-cholesterol rose (7%) and triglycerides decreased (13%) at 12 months with no differences between groups. No changes were seen for fasting glucose or LDL-cholesterol. DISCUSSION AND CONCLUSION The two forms of IER were not statistically different for weight loss, body composition, and cardiometabolic risk factors compared to CER.
Effect of combining pre-exercise carbohydrate intake and repeated short sprints on the blood glucose response to moderate-intensity exercise in young individuals with Type 1 diabetes.
Diabetic medicine : a journal of the British Diabetic Association. 2019;(5):612-619
AIMS: To determine whether pre-exercise ingestion of carbohydrates to maintain stable glycaemia during moderate-intensity exercise results in excessive hyperglycaemia if combined with repeated sprints in individuals with Type 1 diabetes. METHODS Eight overnight-fasted people with Type 1 diabetes completed the following four 40-min exercise sessions on separate days in a randomized counterbalanced order under basal insulinaemic conditions: continuous moderate-intensity exercise at 50% V˙O2 peak; intermittent high-intensity exercise (moderate-intensity exercise interspersed with 4-s sprints every 2 min and a final 10-s sprint); continuous moderate-intensity exercise with prior carbohydrate intake (~10 g per person); and intermittent high-intensity exercise with prior carbohydrate intake. Venous blood was sampled during and 2 h after exercise to measure glucose and lactate levels. RESULTS The difference in marginal mean time-averaged area under the blood glucose curve between continuous moderate-intensity exercise + prior carbohydrate and intermittent high-intensity exercise + prior carbohydrate during exercise and recovery was not significant [0.2 mmol/l (95% CI -0.7, 1.1); P = 0.635], nor was the difference in peak blood glucose level after adjusting for baseline level [0.2 mmol/l (95% CI -0.7, 1.1); P = 0.695]. The difference in marginal mean time-averaged area under the blood glucose curve between continuous moderate-intensity and intermittent high-intensity exercise during exercise and recovery was also not significant [-0.2 mmol/l (95% CI -1.2, 0.8); P = 0.651]. CONCLUSIONS When carbohydrates are ingested prior to moderate-intensity exercise, adding repeated sprints is not significantly detrimental to glycaemic management in overnight fasted people with Type 1 diabetes under basal insulin conditions.
The effect of intermittent compared with continuous energy restriction on glycaemic control in patients with type 2 diabetes: 24-month follow-up of a randomised noninferiority trial.
Diabetes research and clinical practice. 2019;:11-19
AIMS: We investigated the effects of intermittent compared to continuous energy restriction on glycaemic control in patients with type 2 diabetes mellitus. METHODS Adults (N = 137) with type 2 diabetes (mean [SD] HbA1c level, 7.3% (56 mmol/mol) [1.3%] [14.2 mmol/mol]) were randomised to one of two diets for 12 months. The intermittent group (n = 70) followed a 2100-2500 kJ (500-600 kcal) diet 2 non-consecutive days/week and their usual diet for 5 days/week. The continuous group (n = 67) followed a 5000-6300 kJ (1200-1500 kcal) diet for 7 days/week. Follow-up occurred at 24 months, 12 months after the completed intervention. The primary outcome was change in HbA1c and the secondary outcome was weight loss. RESULTS Intention-to-treat analysis showed an increase in mean [SEM] HbA1c level at 24 months in both the continuous and intermittent groups (0.4% [0.3%] vs 0.1% [0.2%] respectively; P = 0.32) (4.4 [3.3 mmol/mol] vs 1.1 [2.2 mmol/mol]; P = 0.32), with a between-group difference of 0.3% (90% CI, -0.31 to 0.83%) (3.3 mmol/mol [90% CI, -3.2 to 9.1 mmol/mol]) outside the prespecified boundary of ± 0.5% (5.5 mmol/mol), so statistical equivalence was not shown. Weight loss was maintained (P < 0.001) at -3.9 kg [1.1 kg] in both groups at 24 months, with a between-group difference of 0.07 kg (90% CI, -2.5 to 2.6 kg) outside the prespecified boundary of ±2.5 kg. There were no significant differences between groups in body composition, fasting glucose levels, lipid levels, or total medication effect score at 24 months, which remained less than baseline. CONCLUSIONS In this prospective analysis weight loss was maintained but despite this HbA1c increased to above baseline levels in both groups.
Abdominal tuberculosis with a Pseudo-Sister Mary Joseph nodule mimicking peritoneal carcinomatosis.
BMJ case reports. 2019;(6)
A 46-year-old woman presented in severe abdominal pain on a background of 3 months of weight loss and intermittent vomiting. She had visited East Africa 6 months prior but reported no unwell contacts. On examination, she had generalised abdominal tenderness, distension and a painful paraumbilical swelling. CT scanning confirmed small bowel obstruction and revealed widespread peritoneal nodules, lymphadenopathy, ascites and a soft tissue paraumbilical mass. CA-125 tumour marker was elevated. However, transvaginal ultrasound scanning showed normal-appearing ovaries. She underwent a diagnostic laparoscopy for ascitic fluid analysis and biopsy of omental and peritoneal nodules, which revealed a lymphocytic exudate and caseating granulomas, respectively. Interferon-γ release assay and repeated stains for acid-fast bacilli were negative. She was commenced on antituberculous chemotherapy for a presumed diagnosis of abdominal tuberculosis. Positive culture results 2 weeks later confirmed Mycobacterium tuberculosis infection. The patient experienced a complete resolution of symptoms within 6 weeks of treatment.
Short-term Intermittent Fasting for Weight Loss: A Case Report.
Intermittent fasting, in which individuals fast periodically, is an increasingly popular weight loss regimen. To understand the short-term effects of such a regimen, we present a case of intermittent fasting with data collection that mimics the single-case design. A healthy but slightly overweight adult male underwent complete fast for two full days and resumed with normal eating for five days, and repeated the cycle three times. Data were collected from three periods: baseline (one week); fasting (three weeks); post-fasting (one week). Measurements taken daily include weight, body fat ratio, temperature, blood pressure, blood glucose, as well as waist and hip circumferences. Blood tests were conducted weekly for safety screening and to obtain observations on lipid profile, high-sensitive C-reactive protein (hsCRP), hemoglobin A1c (HbA1c), and uric acid. The participant lost 1.3 kilograms (kg) in body weight (W̅b = 65.9kg vs W̅p = 64.6kg). Body fat ratio did not differ much (F̅Rb = 19.1% vs F̅Rp = 18.8%). Fasting caused an acute drop in the blood glucose level, which was restored upon resuming normal eating. Total cholesterol dropped drastically immediately after the first fasting cycle but rebounded 15% higher than baseline before dropping down. Fasting also temporarily raised uric acid levels, blood pressure, and body temperature. HbA1c and waist and hip circumferences were not affected by fasting. Improvement in inflammatory marker (hsCRP) was observed (2.0 to 0.3 milligrams per liter, mg/L). This case demonstrates that intermittent fasting can induce short-term weight loss and reduce acute inflammatory marker in a healthy adult, but not body fat ratio and lipid profile. Similar single-case study design can be applied across a practice-based network for inter-case replication.
Time-restricted feeding plus resistance training in active females: a randomized trial.
The American journal of clinical nutrition. 2019;(3):628-640
BACKGROUND A very limited amount of research has examined intermittent fasting (IF) programs, such as time-restricted feeding (TRF), in active populations. OBJECTIVE Our objective was to examine the effects of TRF, with or without β-hydroxy β-methylbutyrate (HMB) supplementation, during resistance training (RT). METHODS This study employed a randomized, placebo-controlled, reduced factorial design and was double-blind with respect to supplementation in TRF groups. Resistance-trained females were randomly assigned to a control diet (CD), TRF, or TRF plus 3 g/d HMB (TRFHMB). TRF groups consumed all calories between 1200 h and 2000 h, whereas the CD group ate regularly from breakfast until the end of the day. All groups completed 8 wk of supervised RT and consumed supplemental whey protein. Body composition, muscular performance, dietary intake, physical activity, and physiological variables were assessed. Data were analyzed prior to unblinding using mixed models and both intention-to-treat (ITT) and per protocol (PP) frameworks. RESULTS Forty participants were included in ITT, and 24 were included in PP. Energy and protein intake (1.6 g/kg/d) did not differ between groups despite different feeding durations (TRF and TRFHMB ∼7.5 h/d; CD: ∼13 h/d). Comparable fat-free mass (FFM) accretion (+2% to 3% relative to baseline) and skeletal muscle hypertrophy occurred in all groups. Differential effects on fat mass (CD: +2%; TRF: -2% to -4%; TRFHMB -4% to -7%) were statistically significant in the PP analysis, but not ITT. Muscular performance improved without differences between groups. No changes in physiological variables occurred in any group, and minimal side effects were reported. CONCLUSIONS IF, in the form of TRF, did not attenuate RT adaptations in resistance-trained females. Similar FFM accretion, skeletal muscle hypertrophy, and muscular performance improvements can be achieved with dramatically different feeding programs that contain similar energy and protein content during RT. Supplemental HMB during fasting periods of TRF did not definitively improve outcomes. This study was prospectively registered at clinicaltrials.gov as NCT03404271.
The Effects of Time Restricted Feeding on Overweight, Older Adults: A Pilot Study.
A growing body of evidence indicates that time restricted feeding (TRF), a popular form of intermittent fasting, can activate similar biological pathways as caloric restriction, the only intervention consistently found to extend healthy lifespan in a variety of species. Thus, TRF may have the potential to also improve function in older adults. Given the challenges many individuals have in following calorie restriction regimens over long-time periods, evaluation of alternative approaches that may produce weight loss and improve function in overweight, older adults is important. Ten overweight, sedentary older adults (≥65 years) at risk for, or with mobility impairments, defined by slow gait speed (<1.0 m/s) participated in this trial. All participants received the intervention and were instructed to fast for approximately 16 h per day over the entire four-week intervention. Outcomes included changes in body weight, waist circumference, cognitive and physical function, health-related quality of life, and adverse events. Adherence levels were high (mean = 84%) based on days goal was met, and mean weight loss was 2.6 kg (p < 0.01). Since body composition was not measured in this study, it is unclear if the observed weight loss was due to loss of fat mass, muscle mass, or the combination of fat and muscle mass. There were no significant changes in other outcomes; however, there were clinically meaningful changes in walking speed and improvements in quality of life, with few reported adverse events. The findings of this pilot study suggest that time restricted feeding is an acceptable and feasible eating pattern for overweight, sedentary older adults to follow.