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Fast track to health - Intermittent energy restriction in adolescents with obesity. A randomised controlled trial study protocol.
Lister, NB, Jebeile, H, Truby, H, Garnett, SP, Varady, KA, Cowell, CT, Collins, CE, Paxton, SJ, Gow, ML, Brown, J, et al
Obesity research & clinical practice. 2020;(1):80-90
Abstract
BACKGROUND Intermittent energy restriction (IER) has shown early success in adolescents with obesity, however efficacy trials are needed. This study aims to determine if IER results in lower body mass index (BMI) z-score after 52 weeks in metabolically unhealthy adolescents with obesity compared with continuous energy restriction (CER). METHODS/DESIGN This is a prospective, randomised, multi-centre trial conducted in tertiary care settings, with three phases: jumpstart (weeks 0-4); intensive intervention (weeks 5-16); continued intervention and/or maintenance (weeks 17-52). During the jumpstart phase, all participants follow a very low energy diet (∼800kcal/3350kJ/day), then transition to their allocated intervention: IER or CER. IER involves three energy-restricted days/week, consuming one-third of daily energy requirements (∼600-700kcal/2500-2950kJ/day), and four days/week of a healthy meal plan. The CER, which is current standard care, has individually tailored energy prescription based on age and sex (13-14years, 1430-1670kcal/6000-7000kJ/day; 15-17years, 1670-1900kcal/7000-8000kJ/day). The study will recruit 186 (93 per arm) treatment-seeking adolescents aged 13-17years with obesity and at least one metabolic co-morbidity. The primary outcome is change in BMI z-score at 52 weeks. Secondary outcomes are changes at 4, 16 and 52 weeks in: body composition; diet quality, food choices and food patterns; cardio-metabolic risk factors; physical activity and sedentary behaviour; sleep and psycho-behavioural measures. DISCUSSION This study challenges existing clinical paradigms that CER is the only method for weight management in metabolically unhealthy adolescents. If successful, IER may offer an alternate medical nutrition therapy approach for those seeking treatment in tertiary settings. CLINICAL TRIAL REGISTRATION NUMBER ACTRN12617001630303.
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Effect of intermittent compared to continuous energy restriction on weight loss and weight maintenance after 12 months in healthy overweight or obese adults.
Headland, ML, Clifton, PM, Keogh, JB
International journal of obesity (2005). 2019;(10):2028-2036
Abstract
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.
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An Evolutionary Perspective on Why Food Overconsumption Impairs Cognition.
Mattson, MP
Trends in cognitive sciences. 2019;(3):200-212
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Abstract
Brain structures and neuronal networks that mediate spatial navigation, decision-making, sociality, and creativity evolved, in part, to enable success in food acquisition. Here, I discuss evidence suggesting that the reason that overconsumption of energy-rich foods negatively impacts cognition is that signaling pathways that evolved to respond adaptively to food scarcity are relatively disengaged in the setting of continuous food availability. Obesity impairs cognition and increases the risk for some psychiatric disorders and dementias. Moreover, maternal and paternal obesity predispose offspring to poor cognitive outcomes by epigenetic molecular mechanisms. Neural signaling pathways that evolved to bolster cognition in settings of food insecurity can be stimulated by intermittent fasting and exercise to support the cognitive health of current and future generations.
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Is two days of intermittent energy restriction per week a feasible weight loss approach in obese males? A randomised pilot study.
Conley, M, Le Fevre, L, Haywood, C, Proietto, J
Nutrition & dietetics: the journal of the Dietitians Association of Australia. 2018;(1):65-72
Abstract
AIM: The 5:2 diet (two non-consecutive days of 2460 KJ (600 calories) and 5 days of ad libitum eating per week) is becoming increasingly popular. This pilot study aimed to determine whether the 5:2 diet can achieve ≥5% weight loss and greater improvements in weight and biochemical markers than a standard energy-restricted diet (SERD) in obese male war veterans. METHODS A total of 24 participants were randomised to consume either the 5:2 diet or a SERD (2050 KJ (500 calorie) reduction per day) for 6 months. Weight, waist circumference (WC), fasting blood glucose, blood lipids, blood pressure and dietary intake were measured at baseline, 3 and 6 months by a blinded investigator. RESULTS After 6 months, participants in both groups significantly reduced body weight (P = <0.001), WC (P = <0.001) and systolic blood pressure (P = 0.001). Mean weight loss was 5.3 ± 3.0 kg (5.5 ± 3.2%) for the 5:2 group and 5.5 ± 4.3 kg (5.4 ± 4.2%) for the SERD group. Mean WC reduction for the 5:2 group was 8.0 ± 4.5 and 6.4 ± 5.8 cm for the SERD group. There was no significant difference in the amount of weight loss or WC reduction between diet groups. There was no significant change in diastolic blood pressure, fasting blood glucose or blood lipids in either dietary group. CONCLUSIONS Results suggest that the 5:2 diet is a successful but not superior weight loss approach in male war veterans when compared to a SERD. Future research is needed to determine the long-term effectiveness of the 5:2 diet and its effectiveness in other population groups.
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Flipping the Metabolic Switch: Understanding and Applying the Health Benefits of Fasting.
Anton, SD, Moehl, K, Donahoo, WT, Marosi, K, Lee, SA, Mainous, AG, Leeuwenburgh, C, Mattson, MP
Obesity (Silver Spring, Md.). 2018;(2):254-268
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Abstract
OBJECTIVE Intermittent fasting (IF) is a term used to describe a variety of eating patterns in which no or few calories are consumed for time periods that can range from 12 hours to several days, on a recurring basis. This review is focused on the physiological responses of major organ systems, including the musculoskeletal system, to the onset of the metabolic switch: the point of negative energy balance at which liver glycogen stores are depleted and fatty acids are mobilized (typically beyond 12 hours after cessation of food intake). RESULTS AND CONCLUSIONS Emerging findings suggest that the metabolic switch from glucose to fatty acid-derived ketones represents an evolutionarily conserved trigger point that shifts metabolism from lipid/cholesterol synthesis and fat storage to mobilization of fat through fatty acid oxidation and fatty acid-derived ketones, which serve to preserve muscle mass and function. Thus, IF regimens that induce the metabolic switch have the potential to improve body composition in overweight individuals. Moreover, IF regimens also induce the coordinated activation of signaling pathways that optimize physiological function, enhance performance, and slow aging and disease processes. Future randomized controlled IF trials should use biomarkers of the metabolic switch (e.g., plasma ketone levels) as a measure of compliance and of the magnitude of negative energy balance during the fasting period.