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A 1-week diet break improves muscle endurance during an intermittent dieting regime in adult athletes: A pre-specified secondary analysis of the ICECAP trial.
Peos, JJ, Helms, ER, Fournier, PA, Krieger, J, Sainsbury, A
PloS one. 2021;(2):e0247292
Abstract
Athletes undergoing energy restriction for weight/fat reduction sometimes apply 'diet breaks' involving increased energy intake, but there is little empirical evidence of effects on outcomes. Twenty-six resistance-trained athletes (11/26 or 42% female) who had completed 12 weeks of intermittent energy restriction participated in this study. Participants had a mean (SD) age of 29.3 (6.4) years, a weight of 72.7 (15.9) kg, and a body fat percentage of 21.3 (7.5) %. During the 1-week diet break, energy intake was increased (by means of increased carbohydrate intake) to predicted weight maintenance requirements. While the 1-week diet break had no significant effect on fat mass, it led to small but significant increases in mean body weight (0.6 kg, P<0.001), fat-free mass (0.7 kg, P<0.001) and in resting energy expenditure, from a mean (and 95% confidence interval) of 7000 (6420 to 7580) kJ/day to 7200 (6620 to 7780) kJ/day (P = 0.026). Overall, muscle endurance in the legs (but not arms) improved after the diet break, including significant increases in the work completed by the quadriceps and hamstrings in a maximum-effort 25-repetition set, with values increasing from 2530 (2170 to 2890) J to 2660 (2310 to 3010) J (P = 0.018) and from 1280 (1130 to 1430) J to 1380 (1220 to 1540) J (P = 0.018) following the diet break, respectively. However, muscle strength did not change. Participants reported significantly lower sensations of hunger (P = 0.017), prospective consumption (P = 0.020) and irritability (P = 0.041) after the diet break, and significantly higher sensations of fullness (P = 0.002), satisfaction (P = 0.002), and alertness (P = 0.003). In summary, a 1-week diet break improved muscle endurance in the legs and increased mental alertness, and reduced appetite and irritability. With this considered, it may be wise for athletes to coordinate diet breaks with training sessions that require muscle endurance of the legs and/or mental focus, as well as in the latter parts of a weight loss phase when increases in appetite might threaten dietary adherence. Trial registration: Australian New Zealand Clinical Trials Registry Reference Number: ACTRN12618000638235 anzctr.org.au.
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Role of the variant in adiponectin gene rs266729 on weight loss and cardiovascular risk factors after a hypocaloric diet with the Mediterranean pattern.
de Luis, DA, Primo, D, Izaola, O, Gomez Hoyos, E, Lopez Gomez, JJ, Ortola, A, Aller, R
Nutrition (Burbank, Los Angeles County, Calif.). 2019;:1-5
Abstract
OBJECTIVES The role of ADIPOQ gene variants on weight loss after a dietary intervention remain unclear. The aim of this study was to analyze the effects of rs266729 of the ADIPOQ gene on cardiovascular risk factors and adiposity parameters after adherence to a Mediterranean-type hypocaloric diet. METHOD Eighty-three obese patients were studied before and after 12 wk on a Mediterranean-type hypocaloric diet. Anthropometric parameters and biochemical profiles were measured. The variant of ADIPOQ gene rs266729 was assessed at basal time by polymerase chain reaction at real time. RESULTS Two genotype groups were realized (CC versus CG + GG). The final genotype distribution was 48 patients CC (57.8%), 30 patients CG (36.2%) and 5 patients GG (6%). After dietary intervention with a moderate calorie restriction and in both genotypes, body mass index (BMI), weight, fat mass, systolic blood pressure, and waist circumference decreased. After dietary intervention and in non-G allele carriers (CC versus CG+ GG), glucose (δ: -6.2 ± 1.1 versus -2.9 ± 1.2 mg/dL; P = 0.02), total cholesterol (δ:-15.2 ± 3.1 versus -3.4 ± 2 mg/dL; P = 0.02), low-density lipoprotein cholesterol (δ, -14.9 ± 3.1 versus -4.9 ± 1.2 mg/dL; P = 0.01), insulin levels (δ, -4± 0.6 versus 0.7 ± 0.3 UI/L;P = 0.01), homeostasis model assessment for insulin resistance (δ, -1.6 ± 0.4 versus -0.2 ± 0.4 units; P = 0.01), and adiponectin (δ, -10.4 ± 3.1 versus -1.3 ± 1.0 ng/dL; P = 0.01) improved. CONCLUSION After weight loss, the CC genotype of ADIPOQ gene variant (rs266729) is associated with increases in adiponectin levels and decreases of low-density lipoprotein cholesterol, insulin and homeostasis model assessment for insulin resistance after weight loss.
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Energy restriction and Roux-en-Y gastric bypass reduce postprandial α-dicarbonyl stress in obese women with type 2 diabetes.
Maessen, DE, Hanssen, NM, Lips, MA, Scheijen, JL, Willems van Dijk, K, Pijl, H, Stehouwer, CD, Schalkwijk, CG
Diabetologia. 2016;(9):2013-7
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Abstract
AIMS/HYPOTHESIS Dicarbonyl compounds are formed as byproducts of glycolysis and are key mediators of diabetic complications. However, evidence of postprandial α-dicarbonyl formation in humans is lacking, and interventions to reduce α-dicarbonyls have not yet been investigated. Therefore, we investigated postprandial α-dicarbonyl levels in obese women without and with type 2 diabetes. Furthermore, we evaluated whether a diet very low in energy (very low calorie diet [VLCD]) or Roux-en-Y gastric bypass (RYGB) reduces α-dicarbonyl stress in obese women with type 2 diabetes. METHODS In lean (n = 12) and obese women without (n = 27) or with type 2 diabetes (n = 27), we measured the α-dicarbonyls, methylglyoxal (MGO), glyoxal (GO) and 3-deoxyglucosone (3-DG), and glucose in fasting and postprandial plasma samples obtained during a mixed meal test. Obese women with type 2 diabetes underwent either a VLCD or RYGB. Three weeks after the intervention, individuals underwent a second mixed meal test. RESULTS Obese women with type 2 diabetes had higher fasting and particularly higher postprandial plasma α-dicarbonyl levels, compared with those without diabetes. After three weeks of a VLCD, postprandial α-dicarbonyl levels in diabetic women were significantly reduced (AUC MGO -14%, GO -16%, 3-DG -25%), mainly through reduction of fasting plasma α-dicarbonyls (MGO -13%, GO -13%, 3-DG -33%). Similar results were found after RYGB. CONCLUSIONS/INTERPRETATION This study shows that type 2 diabetes is characterised by increased fasting and postprandial plasma α-dicarbonyl stress, which can be reduced by improving glucose metabolism through a VLCD or RYGB. These data highlight the potential to reduce reactive α-dicarbonyls in obese individuals with type 2 diabetes. TRIAL REGISTRATION ClinicalTrials.gov NCT01167959.
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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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Abstract
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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Very Low-Calorie Diet and 6 Months of Weight Stability in Type 2 Diabetes: Pathophysiological Changes in Responders and Nonresponders.
Steven, S, Hollingsworth, KG, Al-Mrabeh, A, Avery, L, Aribisala, B, Caslake, M, Taylor, R
Diabetes care. 2016;(5):808-15
Abstract
OBJECTIVE Type 2 diabetes mellitus (T2DM) is generally regarded as an irreversible chronic condition. Because a very low-calorie diet (VLCD) can bring about acute return to normal glucose control in some people with T2DM, this study tested the potential durability of this normalization. The underlying mechanisms were defined. RESEARCH DESIGN AND METHODS People with a T2DM duration of 0.5-23 years (n = 30) followed a VLCD for 8 weeks. All oral agents or insulins were stopped at baseline. Following a stepped return to isocaloric diet, a structured, individualized program of weight maintenance was provided. Glucose control, insulin sensitivity, insulin secretion, and hepatic and pancreas fat content were quantified at baseline, after return to isocaloric diet, and after 6 months to permit the primary comparison of change between post-weight loss and 6 months in responders. Responders were defined as achieving fasting blood glucose <7 mmol/L after return to isocaloric diet. RESULTS Weight fell (98.0 ± 2.6 to 83.8 ± 2.4 kg) and remained stable over 6 months (84.7 ± 2.5 kg). Twelve of 30 participants achieved fasting plasma glucose <7 mmol/L after return to isocaloric diet (responders), and 13 of 30 after 6 months. Responders had a shorter duration of diabetes and a higher initial fasting plasma insulin level. HbA1c fell from 7.1 ± 0.3 to 5.8 ± 0.2% (55 ± 4 to 40 ± 2 mmol/mol) in responders (P < 0.001) and from 8.4 ± 0.3 to 8.0 ± 0.5% (68 ± 3 to 64 ± 5 mmol/mol) in nonresponders, remaining constant at 6 months (5.9 ± 0.2 and 7.8 ± 0.3% [41 ± 2 and 62 ± 3 mmol/mol], respectively). The responders were characterized by return of first-phase insulin response. CONCLUSIONS A robust and sustainable weight loss program achieved continuing remission of diabetes for at least 6 months in the 40% who responded to a VLCD by achieving fasting plasma glucose of <7 mmol/L. T2DM is a potentially reversible condition.
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Increase in cognitive eating restraint predicts weight loss and change in other anthropometric measurements in overweight/obese premenopausal women.
Urbanek, JK, Metzgar, CJ, Hsiao, PY, Piehowski, KE, Nickols-Richardson, SM
Appetite. 2015;:244-50
Abstract
In modern societies characterized by food abundance, dietary restraint may serve as a factor in the successful control of weight or facilitation of weight loss. This secondary analysis of data examined whether changes in cognitive eating restraint (CER) and disinhibition predicted weight loss in a sample of 60 overweight/obese premenopausal women [mean ± SD, age = 35.9 ± 5.8 y; weight = 84.4 ± 13.1 kg; body mass index (BMI) = 31.0 ± 4.3 kg/m(2)]. Changes in weight, BMI, waist circumference, hip circumference, waist-to-hip ratio and body fat percentage (BF%) were examined in relation to changes in CER, disinhibition and hunger as measured by the Eating Inventory questionnaire at baseline and week 18 of an 18-week dietary intervention. Multivariate linear regression analysis was used to identify predictors of weight loss and changes in other anthropometric variables from baseline to study completion. Increase in CER was found to be the most robust predictor of reduction in weight (P < 0.0001), BMI (P < 0.0001), waist circumference (P < 0.001), hip circumference (P < 0.0001) and BF% (P < 0.0001). Effect of increase in CER on change in BMI, hip circumference and BF% was moderated by increase in disinhibition (all P < 0.05). Results suggest that strategies that target CER and disinhibition should be emphasized in programs proposed to treat and prevent obesity.
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Acute exercise reverses starvation-mediated insulin resistance in humans.
Frank, P, Katz, A, Andersson, E, Sahlin, K
American journal of physiology. Endocrinology and metabolism. 2013;(4):E436-43
Abstract
Within 2-3 days of starvation, pronounced insulin resistance develops, possibly mediated by increased lipid load. Here, we show that one exercise bout increases mitochondrial fatty acid (FA) oxidation and reverses starvation-induced insulin resistance. Nine healthy subjects underwent 75-h starvation on two occasions: with no exercise (NE) or with one exercise session at the end of the starvation period (EX). Muscle biopsies were analyzed for mitochondrial function, contents of glycogen, and phosphorylation of regulatory proteins. Glucose tolerance and insulin sensitivity, measured with an intravenous glucose tolerance test (IVGTT), were impaired after starvation, but in EX the response was attenuated or abolished. Glycogen stores were reduced, and plasma FA was increased in both conditions, with a more pronounced effect in EX. After starvation, mitochondrial respiration decreased with complex I substrate (NE and EX), but in EX there was an increased respiration with complex I + II substrate. EX altered regulatory proteins associated with increases in glucose disposal (decreased phosphorylation of glycogen synthase), glucose transport (increased phosphorylation of Akt substrate of 160 kDa), and FA oxidation (increased phosphorylation of acetyl-CoA carboxylase). In conclusion, exercise reversed starvation-induced insulin resistance and was accompanied by reduced glycogen stores, increased lipid oxidation capacity, and activation of signaling proteins involved in glucose transport and FA metabolism.
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Comprehensive Assessment of Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE Phase 2) screening and recruitment: methods and results.
Stewart, TM, Bhapkar, M, Das, S, Galan, K, Martin, CK, McAdams, L, Pieper, C, Redman, L, Roberts, S, Stein, RI, et al
Contemporary clinical trials. 2013;(1):10-20
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Abstract
The Comprehensive Assessment of the Long-term Effects of Reducing Intake of Energy Phase 2 (CALERIE) study is a systematic investigation of sustained 25% calorie restriction (CR) in non-obese humans. CALERIE is a multicenter (3 clinical sites, one coordinating center), parallel group, randomized controlled trial. Participants were recruited, screened, and randomized to the CR or control group with a 2:1 allocation. Inclusion criteria included ages 21-50 years for men and 21-47 years for women, and a body mass index (BMI) of 22.0 ≤ BMI < 28.0 kg/m(2). Exclusion criteria included abnormal laboratory markers, significant medical conditions, psychiatric/behavioral problems, and an inability to adhere to the rigors of the evaluation/intervention schedule. A multi-stage screening process (telephone screen and 3 in-clinic visits) was applied to identify eligible participants. Recruitment was effective and enrollment targets were met on time. 10,856 individuals contacted the clinical sites, of whom 9787 (90%) failed one or more eligibility criteria. Of the 1069 volunteers who started the in-clinic screening, 831 (78%) were either ineligible or dropped. 238 volunteers were enrolled (i.e., initiated the baseline evaluations), 220 were randomized, and 218 started the assigned intervention (2% from the first screening step). This study offered lessons for future multi-center trials engaging non-disease populations. Recruitment strategies must be tailored to specific sites. A multi-disciplinary screening process should be applied to address medical, physical, and psychological/behavioral suitability of participants. Finally, a multi-step screening process with simple criteria first, followed by more elaborate procedures has the potential to reduce the use of study resources.
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The effect of abdominal resistance training and energy restricted diet on lateral abdominal muscles thickness of overweight and obese women.
Noormohammadpour, P, Kordi, R, Dehghani, S, Rostami, M
Journal of bodywork and movement therapies. 2012;(3):344-350
Abstract
The role of transabdominal muscles (external oblique, internal oblique and transversus abdominis) on core stability has been shown previously. Energy restricted diet and abdominal resistance training are commonly used by overweight and obese people to reduce their weight. In this study we investigated the impact of 12 weeks concurrent energy restricted diet and abdominal resistance training on the thickness of the lateral abdominal muscles of 19 obese and overweight women employing ultrasonography in resting and drawing-in maneuvers. The results showed significant increase of the muscle thicknesses during drawing-in maneuver after 12 weeks intervention. Based on our findings, it can be concluded that 12 weeks concurrent abdominal resistance training and energy restricted diet in addition to weight loss lead to improvement of transabdominal muscles thickness in obese and overweight people. Considering the role of these muscles in core stability, using this therapeutic protocol in obese people, particularly in those who have weakness of these muscles might be helpful.
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Low or moderate dietary energy restriction for long-term weight loss: what works best?
Das, SK, Saltzman, E, Gilhooly, CH, DeLany, JP, Golden, JK, Pittas, AG, Dallal, GE, Bhapkar, MV, Fuss, PJ, Dutta, C, et al
Obesity (Silver Spring, Md.). 2009;(11):2019-24
Abstract
Theoretical calculations suggest that small daily reductions in energy intake can cumulatively lead to substantial weight loss, but experimental data to support these calculations are lacking. We conducted a 1-year randomized controlled pilot study of low (10%) or moderate (30%) energy restriction (ER) with diets differing in glycemic load in 38 overweight adults (mean +/- s.d., age 35 +/- 6 years; BMI 27.6 +/- 1.4 kg/m(2)). Food was provided for 6 months and self-selected for 6 additional months. Measurements included body weight, resting metabolic rate (RMR), adherence to the ER prescription assessed using (2)H(2)(18)O, satiety, and eating behavior variables. The 10%ER group consumed significantly less energy (by (2)H(2)(18)O) than prescribed over 12 months (18.1 +/- 9.8%ER, P = 0.04), while the 30%ER group consumed significantly more (23.1 +/- 8.7%ER, P < 0.001). Changes in body weight, satiety, and other variables were not significantly different between groups. However, during self-selected eating (6-12 months) variability in % weight change was significantly greater in the 10%ER group (P < 0.001) and poorer weight outcome on 10%ER was predicted by higher baseline BMI and greater disinhibition (P < 0.0001; adj R(2) = 0.71). Weight loss at 12 months was not significantly different between groups prescribed 10 or 30%ER, supporting the efficacy of low ER recommendations. However, long-term weight change was more variable on 10%ER and weight change in this group was predicted by body size and eating behavior. These preliminary results indicate beneficial effects of low-level ER for some but not all individuals in a weight control program, and suggest testable approaches for optimizing dieting success based on individualizing prescribed level of ER.