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Influence of water-based exercise on energy intake, appetite, and appetite-related hormones in adults: A systematic review and meta-analysis.
Grigg, MJ, Thake, CD, Allgrove, JE, King, JA, Thackray, AE, Stensel, DJ, Owen, A, Broom, DR
Appetite. 2023;180:106375
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Exercise is an effective way to improve mental and physical health and can influence weight management due to the energy expenditure. Energy balance is influenced by day-to-day variations in energy intake and expenditure. The aim of this study was to address whether water-based exercise influences energy intake, appetite, and appetite related hormones differently to land based exercise in adults. This study is a systematic review and meta-analysis of nine studies which include randomised crossover ( 7 trials), semi-random (1 trial) (water-trial was required prior to iso-energetically matched water trial) and independent group (1 trial) (used in the 12-week study) designs. Results show that post-exercise energy intake is higher after water-based exercise versus a resting control. However, there wasn’t any difference in energy intake when water-based exercise was compared with land-based exercise. Furthermore, when different water temperatures were analysed, post-exercise energy intake was higher in cold water versus neutral water. Additionally, cycling and swimming did not alter fasting plasma concentrations of appetite regulating hormones (ghrelin and leptin), insulin or total peptide YY [gut hormone] but contributed to body mass loss. Authors conclude that if body mass management is a person’s primary focus, it is important to be mindful of the tendency to eat more in the subsequent hours after water-based exercise, as energy intake may be increased when compared to a no exercise control.
Expert Review
Conflicts of interest:
None
Take Home Message:
- The only type of exercise reporting an increase in energy intake was in water-based activities, where the temperature was between 18-20• C. However, this was only when explored in comparison to a resting control. No difference was reported in energy intake when water-based exercise was compared with land-based exercise.
- Any form of exercise, whether land or water-based should be considered where appropriate to reduce the risks of sedentary behaviour.
Evidence Category:
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X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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B: Systematic reviews including RCTs of limited number
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C: Non-randomized trials, observational studies, narrative reviews
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D: Case-reports, evidence-based clinical findings
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E: Opinion piece, other
Summary Review:
Introduction:
Exercise is effective for weight-management alongside other physical and mental health benefits. Changes in appetite-regulating hormones may affect energy balance, e.g. some exercise may suppress appetite, known as exercise-induced anorexia. This review evaluated differences in energy intake, appetite and appetite-related hormones in land-based versus water-based exercise.
Methods:
The meta-analysis followed PRISMA guidelines and was registered on PROSPERO. Literature searching resulted in eight studies published between 1991 and 2021, which met the inclusion criteria (water v control), 5 studies (water v land) and 2 studies (water at different temperatures). Risk of Bias was assessed using Cochrane’s Risk of Bias for randomised trials.
Results:
Data were analysed in RevMan 5.4.1 using fixed effects, generic inverse variance method on energy intake. High heterogeneity prevented analysis on appetite and appetite-related hormones. Standard deviation was inputted based on estimated values for missing data. Heterogeneity was calculated using the I2 index. Sensitivity analyses were conducted. Statistical significance was set at p<0.05 and analyses based on two-tailed Z tests.
All participants had a healthy BMI, were aged 19-39 and ranged from well-trained to non-exercisers. A single bout of water-based exercise increased ad-libitum energy intake compared to a non-exercise control (mean difference [95% CI]: 330 [118, 542] kJ, P = 0.002) but no difference was identified between water and land-based exercise (78 [-176, 334] kJ, P = 0.55). Cold water exercise (18–20 •C) increased energy intake more than neutral water (27–33 •C) temperature (719 [222, 1215] kJ; P < 0.005). One 12-week study reported cycling and swimming did not alter fasting plasma concentrations of total ghrelin, insulin, leptin or total PYY but contributed to body mass loss 87.3 (5.2) to 85.9 (5.0) kg and 88.9 (4.9) to 86.4 (4.5) kg (P < 0.05) respectively.
Conclusion:
Despite limitations, this review may provide preliminary evidence on energy intake and appetite for water-based activities. If weight management is a primary focus, then water temperature needs to be considered, particularly if sub 20•C .
Clinical practice applications:
Although this study suggests cold water exercise may cause an increase in energy intake, 95% confidence intervals for individual studies are very large so results should be interpreted cautiously. Those preferring exercise in cold water, should be encouraged, providing they are mindful of the tendency to eat more post-exercise.
It is not possible to draw any robust conclusions about the ratings of hunger in response to different types of exercise due to limited data. However, according to the review, five studies demonstrated that hunger was suppressed more than control prior at the start of water-based exercise, and during and immediately after exercise.
Considerations for future research:
Most participants were of healthy weight and physically active, however since appetite signals may be dysregulated in obesity, including all weight categories and different activity levels may generate a more comprehensive overview.
Further research recommendations include:
- Measuring the effects of water- based activities on appetite, appetite related hormones and energy intake at different time points following exercise in order to provide recommendations for effective weight management strategies and in a range of different temperatures.
- Using a ‘no exercise’ water immersion control. Evidence suggests that immersion in cold water alone may increase energy expenditure
- Evaluating the effect of a water-based activity, such as swimming performed in a ‘fasted’ and ‘non-fasted’ state to investigate the impact on appetite, appetite related hormones and energy intake.
Abstract
Single bouts of land-based exercise suppress appetite and do not typically alter energy intake in the short-term, whereas it has been suggested that water-based exercise may evoke orexigenic effects. The primary aim was to systematically review the available literature investigating the influence of water-based exercise on energy intake in adults (PROSPERO ID number CRD42022314349). PubMed, Medline, Sport-Discus, Academic Search Complete, CINAHL and Public Health Database were searched for peer-reviewed articles published in English from 1900 to May 2022. Included studies implemented a water-based exercise intervention versus a control or comparator. Risk of bias was assessed using the revised Cochrane 'Risk of bias tool for randomised trials' (RoB 2.0). We identified eight acute (same day) exercise studies which met the inclusion criteria. Meta-analysis was performed using a fixed effects generic inverse variance method on energy intake (8 studies (water versus control), 5 studies (water versus land) and 2 studies (water at two different temperatures)). Appetite and appetite-related hormones are also examined but high heterogeneity did not allow a meta-analysis of these outcome measures. We identified one chronic exercise training study which met the inclusion criteria with findings discussed narratively. Meta-analysis revealed that a single bout of exercise in water increased ad-libitum energy intake compared to a non-exercise control (mean difference [95% CI]: 330 [118, 542] kJ, P = 0.002). No difference in ad libitum energy intake was identified between water and land-based exercise (78 [-176, 334] kJ, P = 0.55). Exercising in cold water (18-20 °C) increased energy intake to a greater extent than neutral water (27-33 °C) temperature (719 [222, 1215] kJ; P < 0.005). The one eligible 12-week study did not assess whether water-based exercise influenced energy intake but did find that cycling and swimming did not alter fasting plasma concentrations of total ghrelin, insulin, leptin or total PYY but contributed to body mass loss 87.3 (5.2) to 85.9 (5.0) kg and 88.9 (4.9) to 86.4 (4.5) kg (P < 0.05) respectively. To conclude, if body mass management is a person's primary focus, they should be mindful of the tendency to eat more in the hours after a water-based exercise session, particularly when the water temperature is cold (18-20 °C).
2.
Effect of Dietary Intervention, with or without Cointerventions, on Inflammatory Markers in Patients with Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis.
Hall, RL, George, ES, Tierney, AC, Reddy, AJ
Advances in nutrition (Bethesda, Md.). 2023;14(3):475-499
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Multiple factors, including toxic accumulation of fatty acids in adipose tissue; impaired microbial functioning of the gut; and an imbalance of inflammatory mediators, contribute to a progressed inflammatory state in the liver. The aim of this study was to assess the cumulative effect of evidence regarding the effect of dietary intervention, with or without cointerventions, on the inflammatory profile of adults diagnosed with non-alcoholic fatty liver disease (NAFLD). This study was a systematic review and meta-analysis of forty-four randomised controlled trials. A total of 2579 participants with NAFLD were enrolled in the studies, of whom 2497 participants were analysed. Results (meta-analysis) showed that a hypocaloric diet, when used alone or with supplementation, was the most effective dietary intervention for the improvement of NAFLD-implicated inflammatory markers, adiponectin, and leptin. Whereas isocaloric or energy-balanced dietary interventions provided improvements to the same inflammatory cytokines and adipokines when coupled with supplementation but the benefit was less. Authors conclude that larger sample sizes and longer duration studies are needed in order to better determine the effectiveness of dietary intervention on a NAFLD population.
Abstract
Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of disease from simple steatosis to nonalcoholic steatohepatitis, with inflammatory cytokines and adipokines identified as drivers of disease progression. Poor dietary patterns are known to promote an inflammatory milieu, although the effects of specific diets remain largely unknown. This review aimed to gather and summarize new and existing evidence on the effect of dietary intervention on inflammatory markers in patients with NAFLD. The electronic databases MEDLINE, EMBASE, CINAHL, and Cochrane were searched for clinical trials which investigated outcomes of inflammatory cytokines and adipokines. Eligible studies included adults >18 y with NAFLD, which compared a dietary intervention with an alternative diet or control (no intervention) group or were accompanied by supplementation or other lifestyle interventions. Outcomes for inflammatory markers were grouped and pooled for meta-analysis where heterogeneity was allowed. Methodological quality and risk of bias were assessed using the Academy of Nutrition and Dietetics Criteria. Overall, 44 studies with a total of 2579 participants were included. Meta-analyses indicated intervention with an isocaloric diet plus supplement was more effective in reducing C-reactive protein (CRP) [standard mean difference (SMD): 0.44; 95% CI: 0.20, 0.68; P = 0.0003] and tumor necrosis factor-alpha (TNF-α) (SMD: 0.74; 95% CI: 0.02, 1.46; P = 0.03) than an isocaloric diet alone. No significant weighting was shown between a hypocaloric diet with or without supplementation for CRP (SMD: 0.30; 95% CI: -0.84, 1.44; P = 0.60) and TNF-α (SMD: 0.01; 95% CI: -0.43, 0.45; P = 0.97). In conclusion, hypocaloric and energy-restricted diets alone or with supplementation, and isocaloric diets with supplementation were shown to be most effective in improving the inflammatory profile of patients with NAFLD. To better determine the effectiveness of dietary intervention alone on a NAFLD population, further investigations of longer durations, with larger sample sizes are required.
3.
Body mass index, abdominal fatness, weight gain and the risk of psoriasis: a systematic review and dose-response meta-analysis of prospective studies.
Aune, D, Snekvik, I, Schlesinger, S, Norat, T, Riboli, E, Vatten, LJ
European journal of epidemiology. 2018;33(12):1163-1178
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Psoriasis is an immune-mediated inflammatory skin disease characterised by red, itchy, scaly and flaky skin. Research has shown an association between adiposity and inflammation cytokine release triggered by adipose tissue and increased body mass index and psoriasis. In this meta-analysis, seven prospective studies were included, and the association between BMI, abdominal fat, and psoriasis was examined. According to this meta-analysis, the relative risk of psoriasis increases by 19% for every 5-unit increase in BMI, 24% for a 10 cm increase in waist circumference, 37% for a 0.1-unit increase in waist-to-hip ratio, and 11% for a 5 kg weight gain. The risk of psoriasis was lower for people with a BMI below 20, and it was significantly higher for those with a BMI between 22.5-24. Psoriasis risk was positively associated with waist circumference, waist-to-hip ratio, and weight gain. Psoriasis risk escalates by 2-4 times with an increase in each measure of adiposity. Several potential strategies to reduce the risk of psoriasis are identified in this meta-analysis, including weight loss, dietary factors, and physical activity. To evaluate their effectiveness and develop appropriate strategies, further robust studies are needed. Healthcare professionals can use the results of this study to develop potential therapeutic strategies to reduce the risk of psoriasis by understanding the mechanisms and factors associated with the disease.
Abstract
Greater body mass index (BMI) has been associated with increased risk of psoriasis in case-control and cross-sectional studies, however, the evidence from prospective studies has been limited. We conducted a systematic review and dose-response meta-analysis of different adiposity measures and the risk of psoriasis to provide a more robust summary of the evidence based on data from prospective studies. PubMed and Embase databases were searched for relevant studies up to August 8th 2017. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a random effects model. The summary relative risk (RR) for a 5 unit increment in BMI was 1.19 (95% CI 1.10-1.28, I2 = 83%, n = 7). The association appeared to be stronger at higher compared to lower levels of BMI, pnonlinearity < 0.0001, and the lowest risk was observed at a BMI around 20. The summary RR was 1.24 (95% CI 1.17-1.31, I2 = 0%, pheterogeneity = 0.72, n = 3) per 10 cm increase in waist circumference, 1.37 (95% CI 1.23-1.53, I2 = 0%, pheterogeneity = 0.93, n = 3) per 0.1 unit increase in waist-to-hip ratio, and 1.11 (95% CI 1.07-1.16, I2 = 47%, pheterogeneity = 0.15, n = 3) per 5 kg of weight gain. Adiposity as measured by BMI, waist circumference, waist-to-hip ratio, and weight gain is associated with increased risk of psoriasis.