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Impact of intermittent vs. continuous energy restriction on weight and cardiometabolic factors: a 12-month follow-up.
Headland, ML, Clifton, PM, Keogh, JB
International journal of obesity (2005). 2020;(6):1236-1242
Abstract
BACKGROUND AND OBJECTIVE Intermittent energy restriction continues to gain popularity as a weight loss strategy; however, data assessing it's long-term viability is limited. The objective of this study was to follow up with participants 12 months after they had completed a 12-month dietary intervention trial involving continuous energy restriction and two forms of intermittent energy restriction; a week-on-week-off energy restriction and a 5:2 programme, assessing long-term changes on weight, body composition, blood lipids and glucose. SUBJECTS AND METHODS 109 overweight and obese adults, aged 18-72 years, attended a 12-month follow-up after completing a 12-month dietary intervention involving three groups: continuous energy restriction (1000 kcal/day for women and 1200 kcal/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 (500 kcal/day on modified fast days each week for women and 600 kcal/day for men). The primary outcome was weight change at 24 months from baseline, with secondary outcomes of change in body composition, blood lipids and glucose. RESULTS For the 109 individuals who completed the 12-month follow-up (82 female, 15 male, mean BMI 33 kg/m2), weight decreased over time with no differences between week-on and week-off and continuous energy restriction or 5:2 and continuous energy restriction with -4.5 ± 4.9 kg for continuous energy restriction, -2.8 ± 6.5 kg for week-on, week-off and -3.5 ± 5.1 kg for 5:2. Total cholesterol reduced over time and glucose, HDL, LDL and triglycerides were unchanged. DISCUSSION AND CONCLUSION Intermittent energy restriction was as successful in achieving modest weight loss over a 24-month period as continuous energy restriction.
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Association of rs670 variant of APOA1 gene with lipid profile and insulin resistance after 9 months of a high protein/low carbohydrate vs a standard hypocaloric diet.
Izaola, O, Primo, D, Gomez Hoyos, E, Lopez Gomez, JJ, Ortola, A, de Luis, D
Clinical nutrition (Edinburgh, Scotland). 2020;(4):988-993
Abstract
BACKGROUND & AIMS A common G-to-A transition (rs670) in the APOA1 gene has been related with metabolism. We evaluate the association of this SNP with changes in lipid profile and insulin resistance in response to two diets. METHODS 268 obese patients were randomly allocated to a high protein/low carbohydrate -Diet HP- vs. a standard hypocaloric diet -Diet S- for 9 months. Anthropometric and biochemical status were evaluated at 3 and 9 months. RESULTS 179 subjects (66.8%) had the genotype GG, 79 patients GA (29.4%) and 10 subjects AA (3,8%). With both diets: the decrease of BMI, weight, waist circumference, fat mass was higher in A allele carriers than non-carriers. Also on both diets A allele carriers showed greater improvements in total cholesterol (-19.0 ± 2.5 mg/dl (non-A allele carriers -12.1 ± 2.0 mg/dl:p = 0.02 after Diet HP) and -13.1 ± 2.1 mg/dl (non-A allele carriers -8.9 ± 1.1 mg/dl:p = 0.02 after Diet S)), LDL-cholesterol (-18.0 ± 2.1 mg/dl (non-A allele carriers -8.3 ± 2.2 mg/dl:p = 0.01 after Diet HP) and -12.0 ± 1.5 mg/dl (non-A allele carriers -6.3 ± 2.3 mg/dl:p = 0.01 after Diet S)), insulin (-2.5 ± 0.2 mUI/L (in non A allele -1.8 ± 0.2 mUI/L:p = 0.01 after Diet HP) and -2.1 ± 0.1 mUI/L (non A allele carriers -1.2 ± 0.3 mUI/L:p = 0.01 after Diet S)), HOMA-IR (-1.3 ± 0.3 units (non A allele group -0.8 ± 0.2:p = 0.03 after Diet HP) and -1.1 ± 0.1 units (non A allele carriers -0.3 ± 0.2 mg/dl:p = 0.01 after Diet S)) than non-A allele carriers. CONCLUSIONS A allele carriers of rs670 ApoA1 polymorphism showed a higher decrease of insulin resistance, LDL cholesterol and adiposity induced by two different hypocaloric diet than non A allele carriers.
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Effect of Intermittent Compared With Continuous Energy Restricted Diet on Glycemic Control in Patients With Type 2 Diabetes: A Randomized Noninferiority Trial.
Carter, S, Clifton, PM, Keogh, JB
JAMA network open. 2018;(3):e180756
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Abstract
IMPORTANCE Intermittent energy restriction is an alternative weight loss method that is becoming popular; however, to date, there are no long-term clinical trials of intermittent energy restriction in patients with type 2 diabetes. OBJECTIVE To compare the effects of intermittent energy restriction (2 days per week) with those of continuous energy restriction on glycemic control and weight loss in patients with type 2 diabetes during a 12-month period. DESIGN, SETTING, AND PARTICIPANTS Adult participants (N = 137) with type 2 diabetes were randomized 1:1 to parallel diet groups (intermittent energy restriction [n = 70] or continuous energy restriction [n = 67]) between April 7, 2015, and September 7, 2017, at the University of South Australia. Medications likely to cause hypoglycemia were reduced at baseline according to the medication management protocol. INTERVENTIONS An intermittent energy restriction diet (500-600 kcal/d) followed for 2 nonconsecutive days per week (participants followed their usual diet for the other 5 days) or a continuous energy restriction diet (1200-1500 kcal/d) followed for 7 days per week for 12 months. MAIN OUTCOMES AND MEASURES The primary outcome was change in hemoglobin A1c (HbA1c) level, with equivalence prespecified by a 90% CI margin of ±0.5%. The secondary outcome was weight loss with equivalence set at ±2.5 kg (±1.75 kg for fat mass loss and ±0.75 kg for fat-free mass loss). All other outcomes were tested for superiority. RESULTS Of the 137 randomized participants (77 women and 60 men; mean [SD] age, 61.0 [9.1] years; mean [SD] body mass index, 36.0 [5.8] [calculated as weight in kilograms divided by height in meters squared]; and mean [SD] HbA1c level, 7.3% [1.3%]), 97 completed the trial. Intention-to-treat analysis showed similar reductions in mean (SEM) HbA1c level between the continuous and intermittent energy restriction groups (-0.5% [0.2%] vs -0.3% [0.1%]; P = .65), with a between-group difference of 0.2% (90% CI, -0.2% to 0.5%) meeting the criteria for equivalence. Mean (SEM) weight change was similar between the continuous and intermittent energy restriction groups (-5.0 [0.8] kg vs -6.8 [0.8] kg; P = .25), but the between-group difference did not meet the criteria for equivalence (-1.8 kg; 90% CI, -3.7 to 0.07 kg), nor did the between-group difference in fat mass (-1.3 kg; 90% CI, -2.8 to 0.2 kg) or fat-free mass (-0.5 kg; 90% CI, -1.4 to 0.4 kg). There were no significant differences between groups in final step count, fasting glucose levels, lipid levels, or total medication effect score at 12 months. Effects did not differ using completers analysis. Hypoglycemic or hyperglycemic events in the first 2 weeks of treatment were similar between the continuous and intermittent energy restriction groups (mean number [SEM] of events, 3.2 [0.7] vs 4.9 [1.4]; P = .28), affecting 35% of participants (16 of 46) using sulfonylureas and/or insulin. CONCLUSIONS AND RELEVANCE Intermittent energy restriction is an effective alternative diet strategy for the reduction of HbA1c and is comparable with continuous energy restriction in patients with type 2 diabetes. TRIAL REGISTRATION anzctr.org.au Identifier: ACTRN12615000383561.
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Comparison of Intermittent Fasting Versus Caloric Restriction in Obese Subjects: A Two Year Follow-Up.
Aksungar, FB, Sarıkaya, M, Coskun, A, Serteser, M, Unsal, I
The journal of nutrition, health & aging. 2017;(6):681-685
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OBJECTIVE Caloric restriction (CR) is proven to be effective in increasing life span and it is well known that, nutritional habits, sleeping pattern and meal frequency have profound effects on human health. In Ramadan some Muslims fast during the day-light hours for a month, providing us a unique model of intermittent fasting (IF) in humans. In the present study, we have investigated the effects of IF versus CR on the same non-diabetic obese subjects who were followed for two years according to the growth hormone (GH)/Insulin like growth factor (IGF)-1 axis and insulin resistance. DESIGN Single-arm Interventional Human Study. PARTICIPANTS 23 female subjects (Body Mass Index (BMI) 29-39, aged between 28-42years). SETTING Follow-up is designed as 12 months of CR, after which there was a month of IF and 11 months of CR again, to be totally 24 months. Subjects' daily diets were aligned as low calorie diet during CR and during the IF period, the same subjects fasted for 15 hours in a day for a month and there was no daily calorie restriction. Nutritional pattern was changed as 1 meal in the evening and a late supper before sleeping and no eating and drinking during the day light hours in the IF model. Subjects made brisk walking twice a day during the whole follow-up including both CR and IF periods. BMI, Blood glucose, insulin, TSH, GH, HbA1c, IGF-1, Homa-IR and urinary acetoacetate levels were monitored once in three months and twice in the fasting month. MEASUREMENTS AND RESULTS While subjects lost 1250 ± 372g monthly during the CR, in the IF period, weight loss was decreased to 473 ± 146 g. BMI of all subjects decreased gradually and as the BMI decreased, glucose, HbA1c, insulin, Homa-IR and TSH levels were decreased. GH levels were at baseline at the beginning, increased in the first six months and stayed steady during the CR and IF period than began decreasing after the IF period, while IGF-I increased gradually during the CR period and beginning with the 7th day of IF period, it decreased and kept on decreasing till the end of the follow-up. Urinary acetoacetate levels were higher during the IF period suggesting a constant lipid catabolism. CONCLUSION Our results suggest that, CR affects metabolic parameters positively which will help especially pre-diabetic and insulin resistant patients without any pharmacological approach. In addition IF without calorie restriction can enhance health and cellular resistance to disease without losing weight and those effects may be attributed to different signalling pathways and circulating ketones during IF. Changes observed during IF are probably due to the changes in eating and sleeping pattern and thus changes in metabolic rhythm.
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Preoperative Very Low-Calorie Diet Reduces Technical Difficulty During Laparoscopic Cholecystectomy in Obese Patients.
Jones, AD, Waterland, PW, Powell-Brett, S, Super, P, Richardson, M, Bowley, D
Surgical laparoscopy, endoscopy & percutaneous techniques. 2016;(3):226-9
Abstract
This study investigates the effectiveness of preoperative very low-calorie diet (VLCD) in laparoscopic cholecystectomy. A prospective observational study of consecutive patients undergoing laparoscopic cholecystectomy was undertaken. At the preoperative visit, all patients were advised to adhere to VLCD for 2 weeks before surgery (<800 kcal/d). Patients were judged to have complied with the VLCD if weight loss >2 kg. Technical difficulty was assessed using questionnaires. A total of 38 patients met the inclusion criteria. Difficulty of visualization and dissection of Calot's triangle in obese patients was twice that of nonobese patients (P=0.01). In 62% of procedures involving obese VLCD noncompliant patients, the surgeon experienced ≥1 area of technical difficulty, compared with 0% of procedures on obese, compliant patients (P=0.018). Difficulty of dissection of the gallbladder bed was 3 times higher in obese, noncompliant patients, compared with obese, compliant patients (P=0.07). Adherence to a 2-week preoperative VLCD may reduce technical difficulty of laparoscopic cholecystectomy in obese patients.
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Investigation into the acute effects of total and partial energy restriction on postprandial metabolism among overweight/obese participants.
Antoni, R, Johnston, KL, Collins, AL, Robertson, MD
The British journal of nutrition. 2016;(6):951-9
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The intermittent energy restriction (IER) approach to weight loss involves short periods of substantial (75-100 %) energy restriction (ER) interspersed with normal eating. This study aimed to characterise the early metabolic response to these varying degrees of ER, which occurs acutely and prior to weight loss. Ten (three female) healthy, overweight/obese participants (36 (SEM 5) years; 29·0 (sem 1·1) kg/m2) took part in this acute three-way cross-over study. Participants completed three 1-d dietary interventions in a randomised order with a 1-week washout period: isoenergetic intake, partial 75 % ER and total 100 % ER. Fasting and postprandial (6-h) metabolic responses to a liquid test meal were assessed the following morning via serial blood sampling and indirect calorimetry. Food intake was also recorded for two subsequent days of ad libitum intake. Relative to the isoenergetic control, postprandial glucose responses were increased following total ER (+142 %; P=0·015) and to a lesser extent after partial ER (+76 %; P=0·051). There was also a delay in the glucose time to peak after total ER only (P=0·024). Both total and partial ER interventions produced comparable reductions in postprandial TAG responses (-75 and -59 %, respectively; both P<0·05) and 3-d energy intake deficits of approximately 30 % (both P=0·015). Resting and meal-induced thermogenesis were not significantly affected by either ER intervention. In conclusion, our data demonstrate the ability of substantial ER to acutely alter postprandial glucose-lipid metabolism (with partial ER producing the more favourable overall response), as well as incomplete energy-intake compensation amongst overweight/obese participants. Further investigations are required to establish how metabolism adapts over time to the repeated perturbations experienced during IER, as well as the implications for long-term health.
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A Review of the Effect of Dietary Composition on Fasting Substrate Oxidation in Healthy and Overweight Subjects.
Whelan, ME, Wright, OR, Hickman, IJ
Critical reviews in food science and nutrition. 2016;(1):146-51
Abstract
AIM: The purpose of this review was to assess existing evidence on the effects of chronic dietary macronutrient composition on substrate oxidation during a fasted state in healthy and overweight subjects. METHODS A systematic review of studies was conducted across five databases. Studies were included if they were English language studies of human adults, ≥19 years, used indirect calorimetry (ventilated hood technique), specified dietary macronutrient composition, and measured substrate oxidation. RESULTS There was no evidence that variations of a typical, non-experimental diet influenced rate or ratio of substrate utilization, however there may be an upper and lower threshold for when macronutrient composition may directly alter preferences for fuel oxidation rates during a fasted state. CONCLUSION This review indicates that macronutrient composition of a wide range of typical, non-experimental dietary fat and carbohydrate intakes has no effect on fasting substrate oxidation. This suggests that strict control of dietary intake prior to fasting indirect calorimetry measurements may be an unnecessary burden for study participants. Further research into the effects of long-term changes in isocaloric macronutrient shift is required.
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Effects of Different Dietary Interventions on Blood Pressure: Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Gay, HC, Rao, SG, Vaccarino, V, Ali, MK
Hypertension (Dallas, Tex. : 1979). 2016;(4):733-9
Abstract
Previous studies have shown beneficial effects of individual dietary approaches for blood pressure (BP) control, but their relative effectiveness is not well established. We performed a systematic review of published dietary pattern interventions and estimated the aggregate BP effects through meta-analysis. PubMed, EMBASE, and Web of Science databases were searched to identify studies published between January 1, 1990 and March 1, 2015. Studies meeting specific inclusion and exclusion criteria were selected. Data were pooled using random effects meta-analysis models. Twenty-four trials with 23 858 total participants were included. The overall pooled net effect of dietary intervention on systolic BP and diastolic BP was -3.07 mm Hg (95% confidence interval, -3.85 to -2.30) and -1.81 mm Hg (95% confidence interval, -2.24 to -1.38), respectively. The Dietary Approaches to Stop Hypertension diet had the largest net effect (systolic BP, -7.62 mm Hg [95% confidence interval, -9.95 to -5.29] and diastolic BP, -4.22 mm Hg [95% confidence interval, -5.87 to -2.57]). Low-sodium; low-sodium, high-potassium; low-sodium, low-calorie; and low-calorie diets also led to significant systolic and diastolic BP reductions, whereas Mediterranean diet participants experienced a significant incremental reduction in diastolic but not systolic BP. Subgroup analysis also showed important variations in effectiveness based on duration, size, and participant demographics. In conclusion, dietary modifications are associated with clinically meaningful, though variable, reductions in BP. Some diets are more effective than others and under different circumstances, which has important implications from both clinical and public health perspectives.
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Effects of a caloric restriction weight loss diet on tryptophan metabolism and inflammatory biomarkers in overweight adults.
Strasser, B, Berger, K, Fuchs, D
European journal of nutrition. 2015;(1):101-7
Abstract
PURPOSE Recent data suggest that chronic low-grade inflammation, a characteristic of obesity, is associated with altered tryptophan (Trp) and tyrosine (Tyr) metabolism and plays a role in neuropsychiatric symptoms. The present study assessed the effect of an extreme short-term diet on Trp breakdown and inflammatory biomarkers in overweight adults. METHODS Thirty-eight overweight participants (16 women, 22 men; average body mass index: 29 kg/m², mean age 52.8 years) were randomized into two diet groups: a very low kcal diet group (VLCD; Ø 600 kcal/day, n = 21) and a low kcal diet group (LCD; Ø 1,200 kcal/day, n = 17). Assays included the measurement of Trp, kynurenine (Kyn), and their ratio, neopterin, phenylalanine (Phe), Tyr, as biologic markers; leptin, plasma insulin, glucose, and homeostatic model assessment-insulin resistance; and interleukin 6, tumor necrosis factor alpha, and C-reactive protein, as biochemical and inflammatory markers at baseline and after 2 weeks of treatment. RESULTS Weight loss diet lowered leptin levels in both groups by 46%, although not reaching significance. Trp and Kyn decreased significantly by 21 and 16% for VLCD and by 15 and 17% for the LCD group, respectively. A significant reduction in Phe was only seen after VLCD. Inflammatory biomarkers, neopterin, and Tyr were not significantly altered during the study period. Leptin was significantly correlated with Trp breakdown before and after the intervention (P < 0.02). CONCLUSIONS Since disturbed metabolism of Trp affects biosynthesis of serotonin and might be associated with increased susceptibility for mood disturbances and carbohydrate craving, strategies to supplement Trp while dieting could be highly useful in treating uncontrolled weight gain or in preventing neuropsychiatric symptoms.
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Effect of orlistat on weight loss, hormonal and metabolic profiles in women with polycystic ovarian syndrome: a randomized double-blind placebo-controlled trial.
Moini, A, Kanani, M, Kashani, L, Hosseini, R, Hosseini, L
Endocrine. 2015;(1):286-9