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The Role of Diet Quality in Mediating the Association between Ultra-Processed Food Intake, Obesity and Health-Related Outcomes: A Review of Prospective Cohort Studies.
Dicken, SJ, Batterham, RL
Nutrients. 2021;14(1)
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Diet has long been a cornerstone of weight management, with dietary policies being a core feature of government and health organisation strategies to reduce obesity worldwide. Indeed, poor diets are a leading cause of preventable obesity-related death and non-communicable diseases, including cancer, cardiovascular disease and type 2 diabetes. The aim of this study was to provide novel insights into the relative impact of nutrient content and dietary patterns vs. ultra-processing on obesity and adverse health-related outcomes. This study is a review of prospective cohort studies. Findings show that adjustment for fat, sugar and sodium intake, or adjustment for adherence to a range of healthy or unhealthy dietary patterns has a minimal impact on the adverse associations between UPF intake and a diverse range of health-related outcomes. Authors conclude that their findings raise important questions regarding current policy and future research needs, suggesting that the nature and extent of processing is an important dietary dimension.
Abstract
Prospective cohort studies show that higher intakes of ultra-processed food (UPF) increase the risk of obesity and obesity-related outcomes, including cardiovascular disease, cancer and type 2 diabetes. Whether ultra-processing itself is detrimental, or whether UPFs just have a lower nutritional quality, is debated. Higher UPF intakes are inversely associated with fruit, vegetables, legumes and seafood consumption. Therefore, the association between UPFs and poor health could simply be from excess nutrient intake or from a less healthful dietary pattern. If so, adjustment for dietary quality or pattern should explain or greatly reduce the size of the significant associations between UPFs and health-related outcomes. Here, we provide an overview of the literature and by using a novel approach, review the relative impact of adjusting for diet quality/patterns on the reported associations between UPF intake and health-related outcomes in prospective cohort studies. We find that the majority of the associations between UPFs, obesity and health-related outcomes remain significant and unchanged in magnitude after adjustment for diet quality or pattern. Our findings suggest that the adverse consequences of UPFs are independent of dietary quality or pattern, questioning the utility of reformulation to mitigate against the obesity pandemic and wider negative health outcomes of UPFs.
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Effect of sleep duration on dietary intake, desire to eat, measures of food intake and metabolic hormones: A systematic review of clinical trials.
Soltanieh, S, Solgi, S, Ansari, M, Santos, HO, Abbasi, B
Clinical nutrition ESPEN. 2021;45:55-65
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Adequate sleep is crucial to health. Yet, sleep disturbances have become very common in modern societies. A lack of sleep is linked to increased risk for several chronic diseases such as diabetes, high blood pressure, metabolic syndrome and cardiovascular disease. Furthermore, appetite-regulating hormones can be disrupted by sleep shortages, which is thought to drive chronic overeating, leading to weight gain, obesity and its associated health consequences. This review examined the relationship between sleep duration and food consumption and energy intake, whilst also monitoring changes in body weight and appetite-regulating hormones. The review encompassed 50 randomized controlled trials (RCTs) with 3387 participants, including 1079 children and adolescents and 2308 adults. The findings suggested that sleep shortages contribute to significant increases in calorie intake, fat intake, increased body weight, appetite, hunger, more frequent eating and bigger portion sizes. In this review lack of sleep did not change protein and carbohydrate intake. Nor did lack of sleep make people exert more or less energy overall, however, a variance amongst ethnic groups was observed here. There was not enough evidence for changes in metabolic rate, so the review assumed no significant effect. When viewed collectively, the appetite-regulating hormones of leptin and ghrelin, the stress hormone cortisol and the sugar-regulating hormone insulin were not significantly influenced by sleep duration. However, there seemed to be a wide variance of outcomes when looking at individual studies' results. In conclusion, the authors reiterated the importance of sleep for health maintenance, advocating for a minimum of 7 hours of sleep per day for adults and that, despite busy modern lifestyles, sleep optimisation strategies should be prioritised. Less than 6 hours of sleep per day increases the risk of health consequences, like weight gain and metabolic disorders and sleep management should be considered part of their treatment protocols.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Reduced sleep duration may serve as a mediator for weight gain in part due to increased appetite, increased fat intake and disruptions to energy balance.
- Enhancing sleep quality may serve to support weight loss protocols.
Evidence Category:
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A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
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X
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
Short sleep duration and disruptions to circadian rhythm have been associated with being overweight and obese. It has been suggested that sleep restriction may interfere with appetite regulating hormones leading to increased appetite and disrupted energy balance.
This study aimed to systematically review studies exploring the relationship between sleep duration and food consumption, energy intake, anthropometric characteristics and appetite-regulating hormones.
Methods
This systematic review included 50 randomised controlled trials including 3,387 participants.
Results
Energy intake
- 13 out of 30 the included studies found that short sleep conditions led to higher energy intake.
- 1 study identified that sleep restriction resulted in a 15.3% and 9.2% increase in energy intake in both women and men.
- 3 studies noted that prolonging sleep duration led to a reduction in energy intake.
- 1 study reported a reduction in energy intake after sleep restriction (P=0.031).
Fat consumption
- 9 studies out of 22 identified a significant association between short sleep and increased fat consumption.
- 7 studies did not identify a difference between groups.
- 3 studies noted a decrease in fat consumption following prolonged sleep (P<0.001, P<0.05, P=0.04).
Hunger and appetite
- 11 studies out of 17 observed that sleep restriction resulted in increased hunger ratings.
- 3 studies found an increase in appetite following sleep restriction (P<0.01) with 3 finding no difference..
- 1 study reported a decrease in appetite following sleep restriction.
- 2 studies noted that portion sizes increased as a result of sleep restriction (P<0.01).
- 1 study reported an increase in eating occasions following restricted sleep compared to habitual sleep (6.08 vs 4.96).
Body weight
- 6 studies out of 14 found no effect of sleep loss on body weight.
- 4 studies identified that sleep restriction led to weight gain (P<0.001, P<0.05, P=0.14, P=0.031).
- 2 studies reported weight loss following increased sleep duration (P<0.001).
Ghrelin and leptin
- Leptin and ghrelin levels were generally not found to be influenced by sleep duration, with the exception of a few studies.
Clinical practice applications:
Reduced sleep duration may promote weight gain by:
- Increasing energy intake.
- Increasing fat consumption.
- Increasing hunger and appetite.
- Increasing portion sizes and eating occasions.
Prolonging sleep duration may support weight loss by:
- Reducing energy intake.
- Reducing fat intake.
Considerations for future research:
- Mixed results on the influence of sleep restriction on appetite regulating hormones, leptin and ghrelin.
- Some studies noted the negative impact of sleep restriction on leptin and ghrelin concentrations, collectively shortened sleep duration did not appear to influence these hormones.
- Further sleep restriction studies exploring additional appetite regulating hormones and neuropeptides and the reward system may provide a more definitive understanding of the underlying mechanism for reduced sleep duration to disrupt the appetite and energy balance and promote weight gain.
Abstract
BACKGROUND AND AIMS Sleep, as well as diet and physical activity, plays a significant role in growth, maturation, health, and regulation of energy homeostasis. Recently, there is increasing evidence indicating a possible causal association between sleep duration and energy balance. We aimed to examine the relationship between sleep duration and food consumption, energy intake, anthropometric characteristics, and appetite-regulating hormones by randomized controlled trials (RCTs). METHODS Electronic literature searches were conducted on Medline, Web of Science, and Google Scholar until July 2020. The search was conducted with the following words: "Sleep Duration", "Circadian Rhythm", "Sleep Disorders" in combination with "Obesity", "Overweight", "Abdominal Obesity", "Physical Activity", "Energy Intake", "Body Mass Index", "Lipid Metabolism", "Caloric Restriction", Leptin, "Weight Gain", and "Appetite Regulation" using human studies.methods RESULTS After screening 708 abstracts, 50 RCTs (7 on children or adolescents and 43 on adults) were identified and met the inclusion criteria. In general, the findings suggested that sleep restriction may leads to a significant increment in energy intake, fat intake, body weight, appetite, hunger, eating occasions, and portion size, while protein and carbohydrate consumption, total energy expenditure, and respiratory quotient remained unaffected as a result of sleep restriction. Serum leptin, ghrelin, and cortisol concentrations were not influenced by sleep duration as well. CONCLUSION Insufficient sleep can be considered as a contributing factor for energy imbalance, weight gain, and metabolic disorders and it is suggested that to tackle disordered eating it may be necessary to pay more attention to sleep duration.
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Carbohydrate restriction with postmeal walking effectively mitigates postprandial hyperglycemia and improves endothelial function in type 2 diabetes.
Francois, ME, Myette-Cote, E, Bammert, TD, Durrer, C, Neudorf, H, DeSouza, CA, Little, JP
American journal of physiology. Heart and circulatory physiology. 2018;314(1):H105-H113
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Prevention of cardiovascular disease in individuals with type 2 diabetes (T2D) is a major treatment goal. Within this, diet and exercise remain the cornerstone lifestyle therapies. The aim of this study was to examine the effects of 4 days of a low-carbohydrate diet, with or without daily post-meal walking, on vascular health in individuals with T2D. The study recruited sixteen individuals with physician-diagnosed T2D to complete 3 short-term controlled intervention periods in a randomised crossover design. Results indicate that attenuating postprandial hyperglycaemia (a very high rise in blood sugar following a meal) by restricting carbohydrates and post-meal walking can improve vascular health in individuals with T2D. Authors conclude that carbohydrate restriction and post-meal exercise may represent an effective strategy to mitigate the negative effects of postprandial hyperglycaemia and reduce cardiovascular disease risk in individuals with T2D.
Abstract
Postprandial hyperglycemia has deleterious effects on endothelial function. Restricting carbohydrate intake and postmeal walking have each been shown to reduce postprandial hyperglycemia, but their combination and subsequent effects on endothelial function have not been investigated. Here, we sought to examine the effect of blunting postprandial hyperglycemia by following a low-carbohydrate diet, with or without postmeal walking exercise, on markers of vascular health in type 2 diabetes (T2D). In a randomized crossover design, individuals with T2D ( n = 11) completed three 4-day controlled diet interventions consisting of 1) low-carbohydrate diet alone (LC), 2) low-carbohydrate diet with 15-min postmeal walks (LC + Ex), and 3) low-fat control diet (CON). Fasting blood samples and brachial artery flow-mediated dilation (%FMD) were measured before and after each intervention. Total circulating microparticles (MPs), endothelial MPs, platelet MPs, monocyte-platelet aggregates, and adhesion molecules were assessed as biomarkers of vascular health. There was a significant condition × time interaction for %FMD ( P = 0.01), with post hoc tests revealing improved %FMD after LC + Ex (+0.8 ± 1.0%, P = 0.02), with no change after LC or CON. Endothelial MPs were significantly reduced with the LC diet by ~45% (from 99 ± 60 to 44 ± 31 MPs/μl, P = 0.02), with no change after LC + Ex or CON (interaction: P = 0.04). Total MPs were lower (main effect time: P = 0.02), whereas monocyte-platelet aggregates were higher (main effect time: P < 0.01) after all interventions. Plasma adhesion molecules and C-reactive protein were unaltered. Attenuating postprandial hyperglycemic excursions using a low-carbohydrate diet combined with postmeal walking appears to be an effective strategy to improve endothelial function in individuals with T2D. NEW & NOTEWORTHY Carbohydrate restriction and postmeal walking lower postprandial hyperglycemia in individuals with type 2 diabetes. Here, we show that the combination significantly improved endothelial function and that carbohydrate restriction alone reduced circulating endothelial microparticles in individuals with type 2 diabetes. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/low-carb-diet-and-exercise-improve-endothelial-health/ .
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The Effect of a Diet Moderately High in Protein and Fiber on Insulin Sensitivity Measured Using the Dynamic Insulin Sensitivity and Secretion Test (DISST).
Te Morenga, L, Docherty, P, Williams, S, Mann, J
Nutrients. 2017;9(12)
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The protein, fat and carbohydrate composition of diets can modify heart function abnormalities associated with insulin resistance (when cells in the muscles, fat, and liver do not respond well to insulin and cannot easily take up glucose from the blood) and therefore reduce the risk of diabetes. The aim of the study was to examine the effect of a reduced carbohydrate diet that was high in both protein and dietary fibre on insulin sensitivity and insulin secretion in overweight and obese women at risk of diabetes, independent of weight loss. The study is a randomised control trial which recruited 89 women at risk of diabetes. The participants were randomly assigned to either a standard diet or a relatively high protein and fibre diet group for a period of 10 weeks. Results indicate that a modest increase in consumption of dietary protein and fibre, without emphasis on energy reduction, improved several cardiometabolic risk factors in overweight women. There were modest reductions in body mass, total body fat and central body fat, without loss of lean mass and improvements in total serum and low-density lipoprotein cholesterol levels. Authors conclude that the heart function benefits achieved with moderate increases to fibre and protein, support the use of this dietary approach for overweight individuals at risk of diabetes.
Abstract
Evidence shows that weight loss improves insulin sensitivity but few studies have examined the effect of macronutrient composition independently of weight loss on direct measures of insulin sensitivity. We randomised 89 overweight or obese women to either a standard diet (StdD), that was intended to be low in fat and relatively high in carbohydrate (n = 42) or to a relatively high protein (up to 30% of energy), relatively high fibre (>30 g/day) diet (HPHFib) (n = 47) for 10 weeks. Advice regarding strict adherence to energy intake goals was not given. Insulin sensitivity and secretion was assessed by a novel method-the Dynamic Insulin Sensitivity and Secretion Test (DISST). Although there were significant improvements in body composition and most cardiometabolic risk factors on HPHFib, insulin sensitivity was reduced by 19.3% (95% CI: 31.8%, 4.5%; p = 0.013) in comparison with StdD. We conclude that the reduction in insulin sensitivity after a diet relatively high in both protein and fibre, despite cardiometabolic improvements, suggests insulin sensitivity may reflect metabolic adaptations to dietary composition for maintenance of glucose homeostasis, rather than impaired metabolism.
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Effects of weight loss interventions for adults who are obese on mortality, cardiovascular disease, and cancer: systematic review and meta-analysis.
Ma, C, Avenell, A, Bolland, M, Hudson, J, Stewart, F, Robertson, C, Sharma, P, Fraser, C, MacLennan, G
BMJ (Clinical research ed.). 2017;359:j4849
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Obesity is known to increase the risk of many diseases including cardiovascular disease, various cancers and type 2 diabetes. Interestingly, there is evidence suggesting weight loss in obese adults may be harmful, particularly in older people with cardiovascular disease. The aim of this systematic review was to assess the effect of weight loss interventions for adults with obesity on mortality, cardiovascular disease, cancer and body weight. Based on the 30,000 participants identified, current evidence shows that weight loss interventions significantly decrease all cause mortality. There was also evidence to suggest weight loss is associated with developing new cardiovascular events, though fewer trials reported these outcomes so uncertainty remains around these results. Based on the current literature and this review, the authors conclude weight-reducing diets may reduce all cause mortality in adults with obesity and support public health measures to prevent weight gain and facilitate weight loss.
Abstract
Objective To assess whether weight loss interventions for adults with obesity affect all cause, cardiovascular, and cancer mortality, cardiovascular disease, cancer, and body weight.Design Systematic review and meta-analysis of randomised controlled trials (RCTs) using random effects, estimating risk ratios, and mean differences. Heterogeneity investigated using Cochran's Q and I2 statistics. Quality of evidence assessed by GRADE criteria.Data sources Medline, Embase, the Cochrane Central Register of Controlled Trials, and full texts in our trials' registry for data not evident in databases. Authors were contacted for unpublished data.Eligibility criteria for selecting studies RCTs of dietary interventions targeting weight loss, with or without exercise advice or programmes, for adults with obesity and follow-up ≥1 year.Results 54 RCTs with 30 206 participants were identified. All but one trial evaluated low fat, weight reducing diets. For the primary outcome, high quality evidence showed that weight loss interventions decrease all cause mortality (34 trials, 685 events; risk ratio 0.82, 95% confidence interval 0.71 to 0.95), with six fewer deaths per 1000 participants (95% confidence interval two to 10). For other primary outcomes moderate quality evidence showed an effect on cardiovascular mortality (eight trials, 134 events; risk ratio 0.93, 95% confidence interval 0.67 to 1.31), and very low quality evidence showed an effect on cancer mortality (eight trials, 34 events; risk ratio 0.58, 95% confidence interval 0.30 to 1.11). Twenty four trials (15 176 participants) reported high quality evidence on participants developing new cardiovascular events (1043 events; risk ratio 0.93, 95% confidence interval 0.83 to 1.04). Nineteen trials (6330 participants) provided very low quality evidence on participants developing new cancers (103 events; risk ratio 0.92, 95% confidence interval 0.63 to 1.36).Conclusions Weight reducing diets, usually low in fat and saturated fat, with or without exercise advice or programmes, may reduce premature all cause mortality in adults with obesity.Systematic review registration PROSPERO CRD42016033217.