Effects Of Intermittent Energy Restriction Research Articles

Differential effects of intermittent energy restriction vs. continuous energy restriction combined high-intensity interval training on overweight/obese adults: A randomized controlled trial.

Intermittent energy restriction (IER) and continuous energy restriction (CER) are increasingly popular dietary approaches used for weight loss and overall health. These energy restriction protocols combined with exercise on weight loss and other health outcomes could achieve additional effects in a short-term intervention. To evaluate the effects of a 4-week IER or CER program on weight, blood lipids, and CRF in overweight/obese adults when combined with high-intensity interval training (HIIT). Forty-eight overweight/obese adults [age: 21.3 ± 2.24 years, body mass index (BMI): 25.86 ± 2.64 kg⋅m-2] were randomly assigned to iER, cER, and normal diet (ND) groups (n = 16 per group), each consisting of a 4-week intervention. All of the groups completed HIIT intervention (3 min at 80% of V̇O2max followed by 3 min at 50% of V̇O2max ), 30 min/training sessions, five sessions per week. iER subjects consumed 30% of energy needs on 2 non-consecutive days/week, and 100% of energy needs on another 5 days; cER subjects consumed 70% of energy needs; and ND subjects consumed 100% of energy needs. Body composition, waist circumference (WC) and hip circumference (HC), triglyceride (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-c), high-density lipoprotein-cholesterol (HDL-c), and cardiorespiratory fitness (CRF) were measured before and after the intervention. Of the total 57 participants who underwent randomization, 48 (84.2%) completed the 4-week intervention. After intervention body composition and body circumference decreased in three groups, but no significant differences between groups. The iER tends to be superior to cER in the reduction of body composition and body circumference. The mean body weight loss was 4.57 kg (95% confidence interval [CI], 4.1-5.0, p < 0.001) in iER and 2.46 kg (95% CI, 4.1-5.0, p < 0.001) in iER. The analyses of BMI, BF%, WC, and HC were consistent with the primary outcome results. In addition, TG, TC, HDL-c, and CRF improved after intervention but without significant changes (p > 0.05). Both IER and CER could be effective in weight loss and increased CRF when combined with HIIT. However, iER showed greater benefits for body weight, BF%, WC, and HC compared with cER.

Effects of Intermittent Energy Restriction Alone and in Combination with Sprint Interval Training on Body Composition and Cardiometabolic Biomarkers in Individuals with Overweight and Obesity.

The popularity of intermittent fasting (IF) and high intensity (sprint) interval training (SIT) has increased in recent years amongst the general public due to their purported health benefits and feasibility of incorporation into daily life. The number of scientific studies investigating these strategies has also increased, however, very few have examined the combined effects, especially on body composition and cardiometabolic biomarkers, which is the primary aim of this investigation. A total of thirty-four male and female participants (age: 35.4 ± 8.4 y, body mass index (BMI): 31.3 ± 3.5 kg/m2, aerobic capacity (VO2peak) 27.7 ± 7.0 mL·kg−1·min−1) were randomized into one of three 16-week interventions: (1) 5:2 IF (2 non-consecutive days of fasting per week, 5 days on ad libitum eating), (2) supervised SIT (3 bouts per week of 20s cycling at 150% VO2peak followed by 40 s of active rest, total 10 min duration), and (3) a combination of both interventions. Body composition, haemodynamic and VO2peak were measured at 0, 8 and 16 weeks. Blood samples were also taken and analysed for lipid profiles and markers of glucose regulation. Both IF and IF/SIT significantly decreased body weight, fat mass and visceral fat compared to SIT only (p < 0.05), with no significant differences between diet and diet + exercise combined. The effects of diet and/or exercise on cardiometabolic biomarkers were mixed. Only exercise alone or with IF significantly increased cardiorespiratory fitness. The results suggest that energy restriction was the main driver of body composition enhancement, with little effect from the low volume SIT. Conversely, to achieve benefits in cardiorespiratory fitness, exercise is required.

Comparison of the Effects of Intermittent Energy Restriction and Continuous Energy Restriction among Adults with Overweight or Obesity: An Overview of Systematic Reviews and Meta-Analyses.

There is considerable heterogeneity across the evidence regarding the effects of intermittent energy restriction and continuous energy restriction among adults with overweight or obesity which presents difficulties for healthcare decision-makers and individuals. This overview of systematic reviews aimed to evaluate and synthesize the existing evidence regarding the comparison of the two interventions. We conducted a search strategy in eight databases from the databases’ inception to December 2021. The quality of 12 systematic reviews was assessed with A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) and the Grading of Recommendations Assessment, Development and Evaluation (GRADE). One review was rated as high quality, 1 as moderate, 4 as low, and 6 as critically low. A meta-analysis of the original studies was conducted for comparison of primary intermittent energy restriction protocols with continuous energy restriction. Intermittent energy restriction did not seem to be more effective in weight loss compared with continuous energy restriction. The advantages of intermittent energy restriction in reducing BMI and waist circumference and improvement of body composition were not determined due to insufficient evidence. The evidence quality of systematic reviews and original trials remains to be improved in future studies.

Effects of intermittent energy restriction alone and in combina-tion with sprint interval training on body composition and cardiometabolic biomarkers in overweight and obese individuals

Effects of intermittent energy restriction alone and in combina-tion with sprint interval training on body composition and cardiometabolic biomarkers in overweight and obese individuals

Intermittent Energy Restriction for Weight Loss: A Systematic Review of Cardiometabolic, Inflammatory and Appetite Outcomes.

Current guidelines for obesity treatment recommend reducing daily caloric intake for weight loss. However, long-term weight loss continues to be an issue in obesity management. Alternative weight loss strategies have increased in popularity, such as intermittent energy restriction (IER), a type of eating pattern with periods of fasting alternating with unrestricted eating. The effects of IER on weight loss, cardiovascular risk factors, inflammation, and appetite are not clear. The purpose of this systematic review was to analyze short- (<24weeks) and long-term (≥24weeks) effects of IER on anthropometric, cardiometabolic, inflammatory, and appetite outcomes in adults with overweight/obesity. PubMed, CINAHL, Embase, and PsycInfo were searched from inception to July 2020. Human randomized controlled trials (RCTs) on IER with participants with a body mass index ≥25kg/m2 were included in this review. A total of 42 articles (reporting on 27 different RCTs) were included. In short-term studies, IER showed pre-to-post treatment improvements in eight of nine studies that assessed weight. Weight outcomes were sustained in the long-term. However, no significant long-term between group differences were observed in fat mass, other anthropometric, cardiometabolic, inflammatory, or appetite outcomes. Compared to continuous energy restriction (CER), IER showed no significant long-term differences in anthropometric, cardiometabolic, inflammatory, or appetite outcomes in included studies. More long-term studies are needed to assess the benefits of IER on health outcomes.

The effect of intermittent energy restriction on weight loss and diabetes risk markers in women with a history of gestational diabetes: a 12-month randomized control trial

Weight loss after gestational diabetes (GDM) can prevent or delay the onset of type 2 diabetes. Intermittent energy restriction (IER) may offer an alternative to continuous energy restriction (CER) for weight loss. We compared the effects of IER (2 days per week) to daily CER over 12 mo on weight loss and diabetes risk markers in overweight women with previous GDM. Overweight females (n=121) ≥18 y were randomized 1:1 to either IER [2-d 500 kcal (2100 kJ); n=61] or CER [1500 kcal (6000 kJ); n=60] in this 12-mo noninferiority trial. The trial was completed by 62 participants with a median age of 39.6 y [Quartile (Q) 1 to Quartile 3, 34.9 to 43.9 y] with a median BMI of 32.6 kg/m2 (Q1 to Q3, 28.5 to 37.9 kg/m2) at a median of 2.9 y after GDM (Q1 to Q3, 2.1 to 6.4 y; 49% attrition; IER n=29; CER n=30; P=0.8). The mean±SD weight loss was significant over time (P<0.001) but not by diet group (IER -4.8±5.0 kg; CER -3.2±5.0; P=0.2). The mean between-group difference was -1.6 kg (95% CI: -4.2 to 1.0 kg; P=0.2). There were no significant between-group differences in change in HbA1c, fasting plasma glucose, fasting serum insulin, HOMA-IR or 2-h oral glucose tolerance at 12 mo (p>0.05). The trial was registered at https://www.anzctr.org.au/ (ACTRN12617001476325). IER produces comparable weight loss to CER over 12 mo in overweight women with previous GDM. The high dropout rate in this study is a limitation in the interpretation of these results. Larger studies are needed to confirm noninferiority of IER compared to CER.

Utility of self-rated adherence for monitoring dietary and physical activity compliance and assessment of participant feedback of the Healthy Diet and Lifestyle Study pilot

BackgroundWe examined the utility of self-rated adherence to dietary and physical activity (PA) prescriptions as a method to monitor intervention compliance and facilitate goal setting during the Healthy Diet and Lifestyle Study (HDLS). In addition, we assessed participants’ feedback of HDLS. HDLS is a randomized pilot intervention that compared the effect of intermittent energy restriction combined with a Mediterranean diet (IER + MED) to a Dietary Approaches to Stop Hypertension (DASH) diet, with matching PA regimens, for reducing visceral adipose tissue area (VAT).MethodsAnalyses included the 59 (98%) participants who completed at least 1 week of HDLS. Dietary and PA adherence scores were collected 8 times across 12 weeks, using a 0–10 scale (0 = not at all, 4 = somewhat, and 10 = following the plan very well). Adherence scores for each participant were averaged and assigned to high and low adherence categories using the group median (7.3 for diet, 7.1 for PA). Mean changes in VAT and weight from baseline to 12 weeks are reported by adherence level, overall and by randomization arm. Participants’ feedback at completion and 6 months post-intervention were examined.ResultsMean ± SE, dietary adherence was 6.0 ± 0.2 and 8.2 ± 0.1, for the low and high adherence groups, respectively. For PA adherence, mean scores were 5.9 ± 0.2 and 8.5 ± 0.2, respectively. Compared to participants with low dietary adherence, those with high adherence lost significantly more VAT (22.9 ± 3.7 cm2 vs. 11.7 ± 3.9 cm2 [95% CI, − 22.1 to − 0.3]) and weight at week 12 (5.4 ± 0.8 kg vs. 3.5 ± 0.6 kg [95% CI, − 3.8 to − 0.0]). For PA, compared to participants with low adherence, those with high adherence lost significantly more VAT (22.3 ± 3.7 cm2 vs. 11.6 ± 3.6 cm2 [95% CI, − 20.7 to − 0.8]). Participants’ qualitative feedback of HDLS was positive and the most common response, on how to improve the study, was to provide cooking classes.ConclusionsResults support the use of self-rated adherence as an effective method to monitor dietary and PA compliance and facilitate participant goal setting. Study strategies were found to be effective with promoting compliance to intervention prescriptions.Trial registrationClinicalTrials.gov Identifier: NCT03639350. Registered 21st August 2018—retrospectively registered.

Intermittent Versus Continuous Energy Restriction for Weight Loss and Metabolic Improvement: A Meta-Analysis and Systematic Review.

This study aimed to evaluate the effects of intermittent energy restriction (IER; only for 2-3 d/wk) versus continuous energy restriction (CER) on weight loss and metabolic outcomes in adults with overweight or obesity. Methods included searching databases from the last decade to December 18, 2019, for randomized controlled trials (RCTs) that assessed weight loss and metabolic outcomes in IER and CER. RevMan version 5.3 software was used for statistical analysis of the data. The effect sizes were expressed as weight mean differences and 95% CI. This review included 11 RCTs (n = 850). Meta-analysis showed that IER had greater effects on absolute weight loss, the percentage of weight loss, and improving insulin sensitivity than CER. In the subgroup analysis, short-term (2-3 months) intervention (P < 0.0001) was associated with weight loss. This systematic review shows that IER (2-3 d/wk) had greater effects on short-term weight loss than CER and that IER results in comparative metabolic improvements. Furthermore, longer RCTs are needed to validate these findings.

Effects of Intermittent Energy Restriction Combined with a Mediterranean Diet on Reducing Visceral Adiposity: A Randomized Active Comparator Pilot Study.

Intermittent energy restriction combined with a Mediterranean diet (IER+MED) has shown promise to reduce body fat and insulin resistance. In the Multiethnic Cohort Adiposity Phenotype Study, Japanese Americans had the highest visceral adipose tissue (VAT) when adjusting for total adiposity. We conducted this pilot study to demonstrate feasibility and explore efficacy of following IER+MED for 12 weeks to reduce VAT among East Asians in Hawaii. Sixty volunteers (aged 35–55, BMI 25–40 kg/m2, VAT ≥ 90 cm2 for men and ≥ 80 cm2 for women) were randomized to IER+MED (two consecutive days with 70% energy restriction and 5 days euenergetic MED) or an active comparator (euenergetic Dietary Approaches to Stop Hypertension (DASH) diet). Participants and clinic staff (except dietitians) were blinded to group assignments. IER+MED had significantly larger reductions in DXA-measured VAT and total fat mass (−22.6 ± 3.6 cm2 and −3.3 ± 0.4 kg, respectively) vs. DASH (−10.7 ± 3.5 cm2 and −1.6 ± 0.4 kg) (p = 0.02 and p = 0.005). However, after adjusting for total fat mass, change in VAT was not statistically different between groups; whereas, improvement in alanine transaminase remained significantly greater for IER+MED vs. DASH (−16.2 ± 3.8 U/L vs. −4.0 ± 3.6 U/L, respectively, p = 0.02). Attrition rate was 10%, and participants adhered well to study prescriptions with no reported major adverse effect. Results demonstrate IER+MED is acceptable, lowers visceral and total adiposity among East Asian Americans, and may improve liver function more effectively than a healthful diet pattern. ClinicalTrials.gov Identifier: NCT03639350.

Effects of intermittent versus continuous energy restriction for weight loss on diet quality and eating behavior. A randomized trial.

Weight loss diets affect food choices and control of eating. We evaluated the effects of intermittent energy restriction (IER) vs. continuous energy restriction (CER) on nutritional composition and eating behavior. Individuals with BMI 30-45 kg/m2, abdominal obesity and ≥1 additional metabolic syndrome component were randomized to IER vs. CER with similar energy restriction. Of 112 participants, 98 completed weighed dietary records and the Three Factor Eating Questionnaire at baseline and three months. In statistical analysis, changes were adjusted for baseline values. Weight loss, energy intake, and macronutrient composition were similar in the IER and CER groups. The CER group reported a greater increase in fruit and berries (45 g/day [95% CI 21, 71] vs. 2 g/day [-28, 33]; p = 0.047) and vegetables (135 g/day [91, 179] vs. 65 g/day [35, 96]; p = 0.010) than the IER group. Fiber intake increased in the CER compared to the IER group (1.0 g/MJ/day [0.8, 1.2] vs. 0.2 [0.0, 0.4]; p < 0.001). Sugar intake was reduced in the CER compared to the IER group (-2.2E% [-3.2, -2.2] vs. -0.1E% [-1.2, 1.0]; p = 0.007). Intakes of folate, potassium, and magnesium decreased more in the IER than the CER group, while vitamin C increased more in the CER group (all p-values <0.014). Both diets improved eating behavior scores, but cognitive restraint increased more in the CER than the IER group (34 [30, 39] vs. 17 [12, 22]; p = 0.013). Men and women with obesity had more favorable changes in nutritional composition and eating behavior with CER than IER.

Effect of Intermittent Energy Restriction on Flow Mediated Dilatation, a Measure of Endothelial Function: A Short Report.

Intermittent energy restriction is a popular alternative to daily energy restriction for weight loss; however, it is unknown if endothelial function, a risk factor for cardiovascular disease, is altered by periods of severe energy restriction. The objective of the study was to determine the impact of two consecutive very low energy intake days, which is the core component of the 5:2 intermittent energy restriction diet strategy, on endothelial function compared to consecutive ad libitum eating days. The secondary objective was to explore the effects of these dietary conditions on fasting glucose concentrations. This was a 4-week randomized, single-blinded, crossover study of 35 participants. Participants consumed a very low energy diet (500 calories for women, 600 calories for men) on two consecutive days per week and 5 days of habitual eating. In weeks 3 and 4 of the trial, participants had measurements of flow mediated dilatation (FMD) and blood samples taken following either 2 habitual eating days or 2 energy restricted days in a randomized order. FMD values were not different after the two eating states (8.6% vs. 8.3%, p = 0.7). All other outcome variables were unchanged. Endothelial function, as measured by flow mediated dilatation, was not altered by two consecutive very low energy intake days. Further investigations assessing the impact in specific population groups as well as different testing conditions would be beneficial.

Intermittent fasting interventions for treatment of overweight and obesity in adults: a systematic review and meta-analysis.

To examine the effectiveness of intermittent energy restriction in the treatment for overweight and obesity in adults, when compared to usual care treatment or no treatment. Intermittent energy restriction encompasses dietary approaches including intermittent fasting, alternate day fasting, and fasting for two days per week. Despite the recent popularity of intermittent energy restriction and associated weight loss claims, the supporting evidence base is limited. This review included overweight or obese (BMI ≥25 kg/m) adults (≥18 years). Intermittent energy restriction was defined as consumption of ≤800 kcal on at least one day, but no more than six days per week. Intermittent energy restriction interventions were compared to no treatment (ad libitum diet) or usual care (continuous energy restriction ∼25% of recommended energy intake). Included interventions had a minimum duration of 12 weeks from baseline to post outcome measurements. The types of studies included were randomized and pseudo-randomized controlled trials. The primary outcome of this review was change in body weight. Secondary outcomes included: i) anthropometric outcomes (change in BMI, waist circumference, fat mass, fat free mass); ii) cardio-metabolic outcomes (change in blood glucose and insulin, lipoprotein profiles and blood pressure); and iii) lifestyle outcomes: diet, physical activity, quality of life and adverse events. A systematic search was conducted from database inception to November 2015. The following electronic databases were searched: MEDLINE, Embase, CINAHL, Cochrane Library, ClinicalTrials.gov, ISRCTN registry, and anzctr.org.au for English language published studies, protocols and trials. Two independent reviewers evaluated the methodological quality of included studies using the standardized critical appraisal instruments from the Joanna Briggs Institute. Data were extracted from papers included in the review by two independent reviewers using the standardized data extraction tool from the Joanna Briggs Institute. Effect sizes were expressed as weighted mean differences and their 95% confidence intervals were calculated for meta-analyses. Six studies were included in this review. The intermittent energy restriction regimens varied across studies and included alternate day fasting, fasting for two days, and up to four days per week. The duration of studies ranged from three to 12 months. Four studies included continuous energy restriction as a comparator intervention and two studies included a no treatment control intervention. Meta-analyses showed that intermittent energy restriction was more effective than no treatment for weight loss (-4.14 kg; 95% CI -6.30 kg to -1.99 kg; p ≤ 0.001). Although both treatment interventions achieved similar changes in body weight (approximately 7 kg), the pooled estimate for studies that investigated the effect of intermittent energy restriction in comparison to continuous energy restriction revealed no significant difference in weight loss (-1.03 kg; 95% CI -2.46 kg to 0.40 kg; p = 0.156). Intermittent energy restriction may be an effective strategy for the treatment of overweight and obesity. Intermittent energy restriction was comparable to continuous energy restriction for short term weight loss in overweight and obese adults. Intermittent energy restriction was shown to be more effective than no treatment, however, this should be interpreted cautiously due to the small number of studies and future research is warranted to confirm the findings of this review.

Intermittent fasting interventions for the treatment of overweight and obesity in adults aged 18 years and over: a systematic review and meta-analysis

Objective: To examine the effectiveness of intermittent energy restriction in the treatment for overweight and obesity in adults, when compared to usual care treatment or no treatment. Introduction: Intermittent energy restriction encompasses dietary approaches including intermittent fasting, alternate day fasting, and fasting for two days per week. Despite the recent popularity of intermittent energy restriction and associated weight loss claims, the supporting evidence base is limited. Inclusion criteria: This review included overweight or obese (BMI ≥25 kg/m2) adults (≥18 years). Intermittent energy restriction was defined as consumption of ≤800 kcal on at least one day, but no more than six days per week. Intermittent energy restriction interventions were compared to no treatment (ad libitum diet) or usual care (continuous energy restriction ∼25% of recommended energy intake). Included interventions had a minimum duration of 12 weeks from baseline to post outcome measurements. The types of studies included were randomized and pseudo-randomized controlled trials. The primary outcome of this review was change in body weight. Secondary outcomes included: i) anthropometric outcomes (change in BMI, waist circumference, fat mass, fat free mass); ii) cardio-metabolic outcomes (change in blood glucose and insulin, lipoprotein profiles and blood pressure); and iii) lifestyle outcomes: diet, physical activity, quality of life and adverse events. Methods: A systematic search was conducted from database inception to November 2015. The following electronic databases were searched: MEDLINE, Embase, CINAHL, Cochrane Library, ClinicalTrials.gov, ISRCTN registry, and anzctr.org.au for English language published studies, protocols and trials. Two independent reviewers evaluated the methodological quality of included studies using the standardized critical appraisal instruments from the Joanna Briggs Institute. Data were extracted from papers included in the review by two independent reviewers using the standardized data extraction tool from the Joanna Briggs Institute. Effect sizes were expressed as weighted mean differences and their 95% confidence intervals were calculated for meta-analyses. Results: Six studies were included in this review. The intermittent energy restriction regimens varied across studies and included alternate day fasting, fasting for two days, and up to four days per week. The duration of studies ranged from three to 12 months. Four studies included continuous energy restriction as a comparator intervention and two studies included a no treatment control intervention. Meta-analyses showed that intermittent energy restriction was more effective than no treatment for weight loss (−4.14 kg; 95% CI −6.30 kg to −1.99 kg; p ≤ 0.001). Although both treatment interventions achieved similar changes in body weight (approximately 7 kg), the pooled estimate for studies that investigated the effect of intermittent energy restriction in comparison to continuous energy restriction revealed no significant difference in weight loss (−1.03 kg; 95% CI −2.46 kg to 0.40 kg; p = 0.156). Conclusions: Intermittent energy restriction may be an effective strategy for the treatment of overweight and obesity. Intermittent energy restriction was comparable to continuous energy restriction for short term weight loss in overweight and obese adults. Intermittent energy restriction was shown to be more effective than no treatment, however, this should be interpreted cautiously due to the small number of studies and future research is warranted to confirm the findings of this review.

The effects of intermittent compared to continuous energy restriction on glycaemic control in type 2 diabetes; a pragmatic pilot trial

AimsWeight loss improves glycaemic control in type 2 diabetes mellitus (T2DM). However, as achieving and maintaining weight loss is difficult, alternative strategies are needed. Our primary aim was to investigate the effects of intermittent energy restriction (IER) compared to continuous energy restriction (CER) on glycated haemoglobin A1c (HbA1c). Secondary aims were to assess effects on weight loss, body composition, medication changes and subjective measures of appetite. Using a 2-day IER method, we expected equal improvements to HbA1c and weight in both groups. MethodSixty-three overweight or obese participants (BMI 35.2±5kg/m2) with T2DM (HbA1c 7.4±1.3%) (57mmol/mol) were randomised to a 2-day severe energy restriction (1670-2500kJ/day) with 5days of habitual eating, compared to a moderate CER diet (5000-6500kJ/day) for 12weeks. ResultsAt 12weeks HbA1c (−0.7±0.9% P<0.001) and percent body weight reduction (−5.9±4% P<0.001) was similar in both groups with no group by time interaction. Similar reductions were also seen for medication dosages, all measures of body composition and subjective reports of appetite. ConclusionsIn this pilot trial, 2days of IER compared with CER resulted in similar improvements in glycaemic control and weight reduction offering a suitable alternative treatment strategy.

Weight-Loss Outcomes: A Systematic Review and Meta-Analysis of Intermittent Energy Restriction Trials Lasting a Minimum of 6 Months.

The aim of this systematic review and meta-analysis is to summarise the effects of intermittent energy restriction on weight and biological markers in long term intervention studies of >6 months duration. An electronic search was performed using the MEDLINE, EMBASE and the Cochrane Library databases for intervention trials lasting 6 months or longer investigating the effects of intermittent energy restriction. A total of nine studies were identified as meeting the pre-specified criteria. All studies included an intermittent energy restriction arm, with six being directly compared to continuous energy restriction. A total of 981 subjects were enrolled and randomised, with weight loss observed in all intermittent energy restriction arms regardless of study duration or follow up length. Eight interventions in six trials were used for the meta-analyses, with results indicating neither intermittent or continuous energy restriction being superior with respect to weight loss, 0.084 ± 0.114 (overall mean difference between groups ± standard error; p = 0.458). The effects of intermittent energy restriction in the long term remain unclear. The number of long term studies conducted is very limited, and participant numbers typically small (less than 50 completers), indicating the need for larger, long term trials of 12 months or more, to be conducted in order to understand the impact of intermittent energy restriction on weight loss and long term weight management. Blood lipid concentrations, glucose, and insulin were not altered by intermittent energy expenditure in values greater than those seen with continuous energy restriction.

Investigation into the acute effects of intermittent energy restriction on postprandial substrate metabolism

Investigation into the acute effects of intermittent energy restriction on postprandial substrate metabolism

The Effects of Intermittent Energy Restriction on Indices of Cardiometabolic Health

Intermittent energy restriction (IER) has become the subject of considerable scientific interest as a potential dietary approach for weight-loss and improving cardiometabolic health. This approach involves intermittent periods of total or partial energy restriction (ER) alternated with non-restricted intake, and has been studied in rodent and human populations. This review aims to provide an overview of the IER literature to date, with a specific focus on its effects on cardiometabolic health indices in rodents and humans. Current evidence from studies in rodents and humans suggests that IER is capable of promoting weight-loss and/or favourably influencing an array of cardiometabolic health indices, with equal or greater efficacy than conventional continuous ER approaches. Putative mechanisms include the effects of IER on adipose tissue physiology, stress resistance and fat distribution within visceral and intra-hepatic sites. However, a large proportion of this mechanistic evidence is limited to indirect observations and/or has come from rodent studies requiring translation into humans. Furthermore, whilst there is some indication that total IER and the array of partial IER protocols which have been developed may elicit distinct biological effects, our knowledge around this is limited as only a small number of rodent studies have directly addressed this. Ultimately, whilst much remains to be learned about IER, including its mechanisms of action and long-term efficacy, the positive findings to date serve to highlight promising avenues for future research.

The effect of intermittent versus continuous energy restriction on biomarkers of breast cancer risk.

Abstract Abstract #506 Excess energy, whether it is the form of high energy diets or low energy expenditure (sedentary lifestyle), is a risk factor for breast cancer. Observational studies show that continuous energy restriction (CER) and exercise reduce risk, particularly of postmenopausal breast cancer. Animal data indicate that intermittent energy restriction (IER) may be superior or at least as effective as continuous energy restriction in preventing or reducing the growth rate of mammary tumours. IER may also be more acceptable than CER which has been difficult to implement.&amp;#x2028; We have tested the effectiveness and acceptability of IER and have performed a randomised trial of IER (n=53) versus CER (n=54) in overweight or obese premenopausal women. Energy restriction was 25% in both arms. IER subjects had approximately 550 kcal on 2 days per week and add lib food on other days; CER subjects had approximately 1500 kcal / day over 7 days. Nineteen women (18 %) withdrew from the study before 6 months (IER = 12, CER = 7, main reasons: stress = 4, pregnancy = 3, change in employment = 3, couldn't stick to diet = 3).&amp;#x2028; Change in weight and biomarkers for last observation carried forward are reported.&amp;#x2028; At 6 months. Both IER and CER are effective for loss of weight -7.9 vs. - 6.7% P = 0.26 and waist circumference -6.3 vs. -5% P = 0.13, and for lowering serum levels of leptin -43.3 vs. -39.8% P = 0.53; C – reactive protein -14.8 vs.-20.3% P = 0.15 and free androgen index -9.8 vs.-14.4% P = 0.90. Both IER and CER increased circulating levels of sex hormone binding globulin + 18.1 vs. 10.8% P = 0.51, and plasma adiponectin +11 vs. +1% P = 0.09. IER is better at lowering insulin resistance at 6 months than CER -29.6 vs. -15.3 % P &amp;lt;0.05.&amp;#x2028; These data indicate that 2 days IER gives similar results to CER with respect to weight loss and many of the risk parameters measured and may be an alternative approach to continuous energy restriction. The superior reductions in insulin resistance with IER which may be related to periods of very low calorie intake (approximately 70% restriction). We are waiting data of the effects of IER vs. CER on the IGF-1 axis and oxidative stress. Future studies will investigate the mechanism of IER, its optimal duration and its influence on mammary cell function. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 506.