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Effect of Ramadan Fasting on Weight and Body Composition in Healthy Non-Athlete Adults: A Systematic Review and Meta-Analysis.
Fernando, HA, Zibellini, J, Harris, RA, Seimon, RV, Sainsbury, A
Nutrients. 2019;11(2)
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Ramadan is the Islamic tradition of fasting for one month from sunrise to sunset. Generally, Ramadan is known to impact weight. This systematic review and meta-analysis specifically evaluated the effects of Ramadan on both weight and body mass (fat mass and fat-free mass), pre and post fasting, and in the context of there being no attempt to influence physical activity or diet. The meta-analysis was conducted on 70 publications, 90 comparison groups and 2947 participants. Data was also extracted for diverse sub-groups such as overweight/obese, gender and geographical location. The results showed that Ramadan promoted a significant reduction in weight pre and post fasting across all participants, and that the greater the BMI prior to Ramadan fasting, the greater the weight loss. No significant differences were noted between genders. Weight loss was significant in the Middle East + North Africa, South Asia and South East Asia, but not in Westernized countries. Ramadan fasting promoted a transient reduction in fat mass as a percentage of weight, and absolute fat mass, but quickly returned to pre-fasting levels at follow-up 2-5 weeks later. A significant reduction in fat-free mass was also noted but 30% less than total fat mass. There was insufficient data to analysis the possible impact of physical activity. The authors conclude that Ramadan represents an opportunity for promoting weight and fat loss for people with overweight or obesity but requires strategies for long-term maintenance
Abstract
BACKGROUND Ramadan involves one month of fasting from sunrise to sunset. In this meta-analysis, we aimed to determine the effect of Ramadan fasting on weight and body composition. METHODS In May 2018, we searched six databases for publications that measured weight and body composition before and after Ramadan, and that did not attempt to influence physical activity or diet. RESULTS Data were collected from 70 publications (90 comparison groups, 2947 participants). There was a significant positive correlation between starting body mass index and weight lost during the fasting period. Consistently, there was a significant reduction in fat percentage between pre-Ramadan and post-Ramadan in people with overweight or obesity (-1.46 (95% confidence interval: -2.57 to -0.35) %, p = 0.010), but not in those of normal weight (-0.41 (-1.45 to 0.63) %, p = 0.436). Loss of fat-free mass was also significant between pre-Ramadan and post-Ramadan, but was about 30% less than loss of absolute fat mass. At 2⁻5 weeks after the end of Ramadan, there was a return towards, or to, pre-Ramadan measurements in weight and body composition. CONCLUSIONS Even with no advice on lifestyle changes, there are consistent-albeit transient-reductions in weight and fat mass with the Ramadan fast, especially in people with overweight or obesity.
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Effects of obesity treatments on bone mineral density, bone turnover and fracture risk in adults with overweight or obesity.
Harper, C, Pattinson, AL, Fernando, HA, Zibellini, J, Seimon, RV, Sainsbury, A
Hormone molecular biology and clinical investigation. 2016;(3):133-149
Abstract
BACKGROUND New evidence suggests that obesity is deleterious for bone health, and obesity treatments could potentially exacerbate this. MATERIALS AND METHODS This narrative review, largely based on recent systematic reviews and meta-analyses, synthesizes the effects on bone of bariatric surgery, weight loss pharmaceuticals and dietary restriction. RESULTS AND CONCLUSIONS All three obesity treatments result in statistically significant reductions in hip bone mineral density (BMD) and increases in bone turnover relative to pre-treatment values, with the reductions in hip BMD being strongest for bariatric surgery, notably Roux-en Y gastric bypass (RYGB, 8%-11% of pre-surgical values) and weakest for dietary restriction (1%-1.5% of pre-treatment values). Weight loss pharmaceuticals (orlistat or the glucagon-like peptide-1 receptor agonist, liraglutide) induced no greater changes from pre-treatment values than control, despite greater weight loss. There is suggestive evidence that liraglutide may increase bone mineral content (BMC) - but not BMD - and reduce fracture risk, but more research is required to clarify this. All three obesity treatments have variable effects on spine BMD, probably due to greater measurement error at this site in obesity, suggesting that future research in this field could focus on hip rather than spine BMD. Various mechanisms have been proposed for BMD loss with obesity treatments, notably reduced nutritional intake/absorption and insufficient exercise, and these are potential avenues for protection against bone loss. However, a pressing outstanding question is whether this BMD reduction contributes to increased fracture risk, as has been observed after RYGB, and whether any such increase in fracture risk outweighs the risks of staying obese (unlikely).
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Effect of diet-induced weight loss on muscle strength in adults with overweight or obesity - a systematic review and meta-analysis of clinical trials.
Zibellini, J, Seimon, RV, Lee, CM, Gibson, AA, Hsu, MS, Sainsbury, A
Obesity reviews : an official journal of the International Association for the Study of Obesity. 2016;(8):647-63
Abstract
We conducted a systematic review and meta-analysis to identify how diet-induced weight loss in adults with overweight or obesity impacts on muscle strength. Twenty-seven publications, including 33 interventions, most of which were 8-24 weeks in duration, were included. Meta-analysis of seven interventions measuring knee extensor strength by isokinetic dynamometry in 108 participants found a significant decrease following diet-induced weight loss (-9.0 [95% confidence interval: -13.8, -4.1] N/m, P < 0.001), representing a 7.5% decrease from baseline values. Meta-analysis of handgrip strength from 10 interventions in 231 participants showed a non-significant decrease (-1.7 [-3.6, 0.1] kg, P = 0.070), with significant heterogeneity (I(2) = 83.9%, P < 0.001). This heterogeneity may have been due to diet type, because there was a significant decrease in handgrip strength in seven interventions in 169 participants involving moderate energy restriction (-2.4 [-4.8, -0.0] kg, P = 0.046), representing a 4.6% decrease from baseline values, but not in three interventions in 62 participants involving very-low-energy diet (-0.4 [-2.0, 1.2] kg, P = 0.610). Because of variability in methodology and muscles tested, no other data could be meta-analyzed, and qualitative assessment of the remaining interventions revealed mixed results. Despite varying methodologies, diets and small sample sizes, these findings suggest a potential adverse effect of diet-induced weight loss on muscle strength. While these findings should not act as a deterrent against weight loss, due to the known health benefits of losing excess weight, they call for strategies to combat strength loss - such as weight training and other exercises - during diet-induced weight loss. © 2016 World Obesity.
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Do intermittent diets provide physiological benefits over continuous diets for weight loss? A systematic review of clinical trials.
Seimon, RV, Roekenes, JA, Zibellini, J, Zhu, B, Gibson, AA, Hills, AP, Wood, RE, King, NA, Byrne, NM, Sainsbury, A
Molecular and cellular endocrinology. 2015;:153-72
Abstract
Energy restriction induces physiological effects that hinder further weight loss. Thus, deliberate periods of energy balance during weight loss interventions may attenuate these adaptive responses to energy restriction and thereby increase the efficiency of weight loss (i.e. the amount of weight or fat lost per unit of energy deficit). To address this possibility, we systematically searched MEDLINE, PreMEDLINE, PubMed and Cinahl and reviewed adaptive responses to energy restriction in 40 publications involving humans of any age or body mass index that had undergone a diet involving intermittent energy restriction, 12 with direct comparison to continuous energy restriction. Included publications needed to measure one or more of body weight, body mass index, or body composition before and at the end of energy restriction. 31 of the 40 publications involved 'intermittent fasting' of 1-7-day periods of severe energy restriction. While intermittent fasting appears to produce similar effects to continuous energy restriction to reduce body weight, fat mass, fat-free mass and improve glucose homeostasis, and may reduce appetite, it does not appear to attenuate other adaptive responses to energy restriction or improve weight loss efficiency, albeit most of the reviewed publications were not powered to assess these outcomes. Intermittent fasting thus represents a valid--albeit apparently not superior--option to continuous energy restriction for weight loss.
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Does Diet-Induced Weight Loss Lead to Bone Loss in Overweight or Obese Adults? A Systematic Review and Meta-Analysis of Clinical Trials.
Zibellini, J, Seimon, RV, Lee, CM, Gibson, AA, Hsu, MS, Shapses, SA, Nguyen, TV, Sainsbury, A
Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research. 2015;(12):2168-78
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Abstract
Diet-induced weight loss has been suggested to be harmful to bone health. We conducted a systematic review and meta-analysis (using a random-effects model) to quantify the effect of diet-induced weight loss on bone. We included 41 publications involving overweight or obese but otherwise healthy adults who followed a dietary weight-loss intervention. The primary outcomes examined were changes from baseline in total hip, lumbar spine, and total body bone mineral density (BMD), as assessed by dual-energy X-ray absorptiometry (DXA). Secondary outcomes were markers of bone turnover. Diet-induced weight loss was associated with significant decreases of 0.010 to 0.015 g/cm(2) in total hip BMD for interventions of 6, 12, or 24 (but not 3) months' duration (95% confidence intervals [CIs], -0.014 to -0.005, -0.021 to -0.008, and -0.024 to -0.000 g/cm(2), at 6, 12, and 24 months, respectively). There was, however, no statistically significant effect of diet-induced weight loss on lumbar spine or whole-body BMD for interventions of 3 to 24 months' duration, except for a significant decrease in total body BMD (-0.011 g/cm(2); 95% CI, -0.018 to -0.003 g/cm(2)) after 6 months. Although no statistically significant changes occurred in serum concentrations of N-terminal propeptide of type I procollagen (P1NP), interventions of 2 or 3 months in duration (but not of 6, 12, or 24 months' duration) induced significant increases in serum concentrations of osteocalcin (0.26 nmol/L; 95% CI, 0.13 to 0.39 nmol/L), C-terminal telopeptide of type I collagen (CTX) (4.72 nmol/L; 95% CI, 2.12 to 7.30 nmol/L) or N-terminal telopeptide of type I collagen (NTX) (3.70 nmol/L; 95% CI, 0.90 to 6.50 nmol/L bone collagen equivalents [BCEs]), indicating an early effect of diet-induced weight loss to promote bone breakdown. These data show that in overweight and obese individuals, a single diet-induced weight-loss intervention induces a small decrease in total hip BMD, but not lumbar spine BMD. This decrease is small in comparison to known metabolic benefits of losing excess weight.