scholarly journals 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

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247292
Author(s):  
Jackson J. Peos ◽  
Eric R. Helms ◽  
Paul A. Fournier ◽  
James Krieger ◽  
Amanda Sainsbury

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.

1993 ◽  
Vol 3 (2) ◽  
pp. 194-206 ◽  
Author(s):  
Janice Thompson ◽  
Melinda M. Manore ◽  
James S. Skinner

The resting metabolic rate (RMR) and thermic effect of a meal (TEM) were determined in 13 low-energy intake (LOW) and 11 adequate-energy intake (ADQ) male endurance athletes. The LOW athletes reported eating 1,490 kcal·day-1less than the ADQ group, while the activity level of both groups was similar. Despite these differences, both groups had a similar fat-free mass (FFM) and had been weight stable for at least 2 years. The RMR was significantly lower (p<0.05) in the LOW group compared to the values of the ADQ group (1.19 vs. 1.29 kcal·FFM-1·hr-l, respectively); this difference represents a lower resting expenditure of 158 kcal·day-1. No differences were found in TEM between the two groups. These results suggest that a lower RMR is one mechanism that contributes to weight maintenance in a group of low- versus adequate-energy intake male athletes.


2000 ◽  
Vol 85 (4) ◽  
pp. 1550-1556 ◽  
Author(s):  
Eric Doucet ◽  
Sylvie St. Pierre ◽  
Natalie Alméras ◽  
Pascale Mauriège ◽  
Denis Richard ◽  
...  

The aim of the present study was to determine the impact of weight loss and its related metabolic and hormonal changes on resting energy expenditure (REE) and substrate oxidation. Forty subjects (16 men and 24 women) took part in a 15-week weight loss program that consisted of drug therapy (fenfluramine, 60 mg/day) or placebo coupled to an energy restriction (−700 Cal/day). Subjects were asked to come to the laboratory after an overnight fast for an indirect calorimetry measurement before and after weight loss. Fasting blood samples were also drawn and were analyzed for plasma glucose, insulin, leptin, and free fatty acid determinations. This program reduced body weight by 11% and 9% (P &lt; 0.01) in men and women, respectively. Fat mass (FM) and fat-free mass (FFM) were also significantly reduced in both sexes. A significant decrease in REE (13%; P &lt; 0.01) and fat oxidation (11%; P = 0.08) was observed in men in response to this program, whereas no significant differences were noted for these variables in women. In men, positive correlations were found between changes in FFM and energy-related variables, whereas the best predictor of changes in REE and substrate oxidation was the change in FM in women. The most important finding of this study is that in men, the association between changes in fasting plasma leptin and changes in REE (r = 0.50; P &lt; 0.01) and fat oxidation (r = 0.63; P &lt; 0.01) persist after correction for changes in body composition. These results suggest that a comparable weight loss is accompanied by a greater decrease in REE and substrate oxidation in men than in women, and that these changes are better explained by changes in leptinemia in men and by changes in FM in women.


2020 ◽  
Vol 150 (4) ◽  
pp. 800-805
Author(s):  
Noor A Struik ◽  
Grant D Brinkworth ◽  
Campbell H Thompson ◽  
Jonathan D Buckley ◽  
Gary Wittert ◽  
...  

ABSTRACT Background Effects of very low carbohydrate (VLC) diets on appetite response in individuals with type 2 diabetes remain unclear. Objective A secondary analysis was conducted to determine appetite responses to an energy-restricted [30% of energy (%E) deficit] very low carbohydrate (VLC) diet compared with a higher carbohydrate (HC) diet in adults who were overweight or obese with type 2 diabetes. Methods Forty-four men and 40 women (mean ± SD, age: 58.7 ± 6.6 y; weight: 100.4 ± 15.5 kg; BMI: 34.5 ± 4.1 kg/m2; glycated hemoglobin: 7.3 ± 1.0%; duration of diabetes: 6.7 ± 5.6 y) were randomly assigned to diets categorized as VLC [14%E carbohydrate (&lt;50 g/d), 28%E protein, 58%E fat (&lt;10%E saturated fat)], or energy-matched HC [53%E carbohydrate, 17%E protein, 30%E fat (&lt;10%E saturated fat)] combined with progressive multicomponent exercise (60 min; 3 d/wk). Body weight, average weekly “daily fasting” and “daily overall” appetite perceptions (hunger, fullness, prospective consumption, and desire to eat—visual analog scales) were assessed at baseline and after 4 and 16 wk. Changes between diets over time were assessed using repeated measures ANOVA. Results Significant decreases in body weight did not differ between groups (VLC: −11.0 ± 5.4 kg/16 wk compared with HC: −10.1 ± 4.3 kg/16 wk, P = 0.40). Compared with HC, VLC had greater decreases in “daily overall” ratings of fullness (P time × diet &lt; 0.01), such that scores were higher in HC at Week 4 (VLC:48 ± 3 vs HC:56 ± 3 mm, P = 0.001) and 16 (VLC:51 ± 2 vs HC:57 ± 3 mm, P = 0.019). Compared with HC, VLC had greater increases in prospective consumption ratings (P time × diet = 0.03), such that scores were lower in HC at Week 4 (VLC:33 ± 2 vs HC:28 ± 2 mm, P = 0.008), but not at Week 16 (VLC:33 ± 2 vs HC 31 ± 2 mm, P = 0.289). Conclusions In the context of energy restriction, both HC and VLC energy-matched diets promoted comparable effects on fasting perceptions of appetite, but the HC diet resulted in greater “daily overall” fullness and reduced prospective consumption. Further research is required to evaluate the effects of ad libitum diets differing in amounts of carbohydrate on appetite response in populations with type 2 diabetes. This trial was registered at www.anzctr.org.au as ACTRN12612000369820.


1993 ◽  
Vol 264 (5) ◽  
pp. E706-E711 ◽  
Author(s):  
M. I. Goran ◽  
W. H. Carpenter ◽  
E. T. Poehlman

There is a sparsity of data on energy expenditure in young children. We therefore examined the components of daily energy expenditure in a group of 30 children (16 boys, 14 girls; age 4–6 yr) characterized for body weight, height, heart rate, and body composition from bioelectrical resistance. Total energy expenditure (TEE) was measured over 14 days under free living conditions by doubly labeled water, resting energy expenditure (REE) from indirect calorimetry, and activity energy expenditure was estimated from the difference between TEE and REE. Mean TEE was 1,379 +/- 290 kcal/day, which was 475 +/- 202 kcal/day lower than energy intake recommendations for this age group. Activity-related energy expenditure was estimated to be 267 +/- 203 kcal/day. TEE was most significantly related to fat-free mass (FFM; r = 0.86; P < 0.001), body weight (r = 0.83; P < 0.001), and REE (r = 0.80; P < 0.001). When TEE was adjusted for FFM, a significant correlation with heart rate was observed (partial r = 0.54; P = 0.002). Collectively, 86% of interindividual variation in TEE was accounted for by FFM, heart rate, and REE. We conclude that, in young 4- to 6-yr-old children, 1) TEE is approximately 25% lower than current recommendations for energy intake and 2) combined measurement of FFM, heart rate, and REE explain 86% of interindividual variation in TEE, thus providing a possible alternative method to estimate TEE in young children.


2019 ◽  
Vol 150 (3) ◽  
pp. 458-463 ◽  
Author(s):  
Mathijs Drummen ◽  
Lea Tischmann ◽  
Blandine Gatta-Cherifi ◽  
Mikael Fogelholm ◽  
Anne Raben ◽  
...  

ABSTRACT Background Weight loss has been associated with adaptations in energy expenditure. Identifying factors that counteract these adaptations are important for long-term weight loss and weight maintenance. Objective The aim of this study was to investigate whether increased protein/carbohydrate ratio would reduce adaptive thermogenesis (AT) and the expected positive energy balance (EB) during weight maintenance after weight loss in participants with prediabetes in the postobese state. Methods In 38 participants, the effects of 2 diets differing in protein/carbohydrate ratio on energy expenditure and respiratory quotient (RQ) were assessed during 48-h respiration chamber measurements ∼34 mo after weight loss. Participants consumed a high-protein (HP) diet (n = 20; 13 women/7 men; age: 64.0 ± 6.2 y; BMI: 28.9 ± 4.0 kg/m 2) with 25:45:30% or a moderate-protein (MP) diet (n = 18; 9 women/9 men; age: 65.1 ± 5.8 y; BMI: 29.0 ± 3.8 kg/m 2) with 15:55:30% of energy from protein:carbohydrate:fat. Predicted resting energy expenditure (REEp) was calculated based on fat-free mass and fat mass. AT was assessed by subtracting measured resting energy expenditure (REE) from REEp. The main outcomes included differences in components of energy expenditure, substrate oxidation, and AT between groups. Results EB (MP = 0.2 ± 0.9 MJ/d; HP = −0.5 ± 0.9 MJ/d) and RQ (MP = 0.84 ± 0.02; HP = 0.82 ± 0.02) were reduced and REE (MP: 7.3 ± 0.2 MJ/d compared with HP: 7.8 ± 0.2 MJ/d) was increased in the HP group compared with the MP group (P &lt; 0.05). REE was not different from REEp in the HP group, whereas REE was lower than REEp in the MP group (P &lt; 0.05). Furthermore, EB was positively related to AT (rs = 0.74; P &lt; 0.001) and RQ (rs = 0.47; P &lt; 0.01) in the whole group of participants. Conclusions In conclusion, an HP diet compared with an MP diet led to a negative EB and counteracted AT ∼34 mo after weight loss, in participants with prediabetes in the postobese state. These results indicate the relevance of compliance to an increased protein/carbohydrate ratio for long-term weight maintenance after weight loss. The trial was registered at clinicaltrials.gov as NCT01777893.


2001 ◽  
Vol 85 (6) ◽  
pp. 715-723 ◽  
Author(s):  
Eric Doucet ◽  
Sylvie St-Pierre ◽  
Natalie Alméras ◽  
Jean-Pierre Després ◽  
Claude Bouchard ◽  
...  

The present study was performed to further investigate the adaptive component of thermogenesis that appears during prolonged energy restriction. Fifteen obese men and twenty obese women underwent a 15-week weight-loss programme. During this programme, body weight and composition as well as resting energy expenditure (REE) were measured at baseline, after 2 and 8 weeks of energy restriction (-2929 kJ/d) and drug therapy (or placebo), and finally 2–4 weeks after the end of the 15-week drug therapy and energy restriction intervention, when subjects were weight stable. Regression equations were established in a control population of the same age. These equations were then used to predict REE in obese men and women at baseline, after 2 and 8 weeks, as well as after the completion of the programme. In both men and women body weight and fat mass were significantly reduced (P < 0.05 in all cases) while fat-free mass remained unchanged throughout the programme. At baseline, REE predicted from the regression equation was not significantly different from the measured REE in men, while in women the measured REE was 13 % greater than predicted. After 2 weeks of energy restriction, measured REE had fallen by 469 and 635 kJ/d more than predicted and this difference reached 963 and 614 kJ/d by week 8 of treatment in men and women respectively. Once body-weight stability was recovered at the end of the programme, changes in REE remained below predicted changes in men (-622 kJ/d). However, in women changes in predicted and measured REE were no longer different at this time, even if the women were maintaining a reduced body weight. In summary, the present results confirm the existence of adaptive thermogenesis and give objective measurements of this component during weight loss in obese men and women, while they also emphasize that in women this component seems to be essentially explained by the energy restriction.


2008 ◽  
Vol 33 (6) ◽  
pp. 1250-1256 ◽  
Author(s):  
Krystal J. Merrells ◽  
James K. Friel ◽  
Maria Knaus ◽  
Miyoung Suh

Lower body fat percentage is positively associated with climbing performance. This may lead climbers to practice unhealthy diet restriction when no sport-specific nutrition information exists. This study examined whether prolonged diet restriction affects body composition, oxidative stress, or other potential health risks in outdoor rock climbers. Two healthy male climbers conducted a 5 week rock climbing trip with a limited food budget ($1 each per day). Subjects underwent an energy restriction of approximately 40%. Loss of body weight and fat mass at week 5 were 5.8% and 16.1%, respectively, and were accompanied by significant subcutaneous fat loss in the iliac crest and abdomen. Triacylglycerols (TG), free fatty acids and C-reactive protein (CRP) dramatically decreased from baseline to week 2, and then maintained the lower level until week 5. Plasma vitamin C was below the normal range, and F2-isoprostanes, a marker of oxidative stress, continuously increased to week 5. Superoxide dismutase and glutathione peroxidase increased to week 2, but had returned to baseline levels at week 5. These results indicate that prolonged reduced energy intake while climbing may have an impact on weight loss and fat mass loss, which may contribute to low circulating TG and CRP, indicating improvements in markers of cardiovascular risk, and may lead to increased oxidative stress and reduced circulating antioxidants. Further studies are warranted to determine whether antioxidant supplementation or increased energy intake reduce oxidative stress.


2009 ◽  
Vol 103 (7) ◽  
pp. 939-943 ◽  
Author(s):  
Emilienne Tudor Ngo Sock ◽  
Kim-Anne Lê ◽  
Michael Ith ◽  
Roland Kreis ◽  
Chris Boesch ◽  
...  

Consumption of simple carbohydrates has markedly increased over the past decades, and may be involved in the increased prevalence in metabolic diseases. Whether an increased intake of fructose is specifically related to a dysregulation of glucose and lipid metabolism remains controversial. We therefore compared the effects of hypercaloric diets enriched with fructose (HFrD) or glucose (HGlcD) in healthy men. Eleven subjects were studied in a randomised order after 7 d of the following diets: (1) weight maintenance, control diet; (2) HFrD (3·5 g fructose/kg fat-free mass (ffm) per d, +35 % energy intake); (3) HGlcD (3·5 g glucose/kg ffm per d, +35 % energy intake). Fasting hepatic glucose output (HGO) was measured with 6,6-2H2-glucose. Intrahepatocellular lipids (IHCL) and intramyocellular lipids (IMCL) were measured by 1H magnetic resonance spectroscopy. Both fructose and glucose increased fasting VLDL-TAG (HFrD: +59 %, P < 0·05; HGlcD: +31 %, P = 0·11) and IHCL (HFrD: +52 %, P < 0·05; HGlcD: +58 %, P = 0·06). HGO increased after both diets (HFrD: +5 %, P < 0·05; HGlcD: +5 %, P = 0·05). No change was observed in fasting glycaemia, insulin and alanine aminotransferase concentrations. IMCL increased significantly only after the HGlcD (HFrD: +24 %, NS; HGlcD: +59 %, P < 0·05). IHCL and VLDL-TAG were not different between hypercaloric HFrD and HGlcD, but were increased compared to values observed with a weight maintenance diet. However, glucose led to a higher increase in IMCL than fructose.


2007 ◽  
Vol 292 (3) ◽  
pp. E687-E692 ◽  
Author(s):  
Jussi Sutinen ◽  
Hannele Yki-Järvinen

Highly active antiretroviral therapy (HAART) is associated with metabolic adverse events such as lipodystrophy in human immunodeficiency virus (HIV)-infected patients. The objective of the present study was to evaluate the effects of HAART-associated lipodystrophy on resting energy expenditure and caloric intake. In this cross-sectional study we compared resting energy expenditure (REE) and energy intake in 30 HAART-treated patients with lipodystrophy (HAART+LD+) with 13 HAART-treated patients without lipodystrophy (HAART+LD−). REE was measured using indirect calorimetry, and energy intake was recorded as a 3-day diary of food intake. REE (5,180 ± 160 vs. 4,260 ± 150 J/min, P < 0.01) and also REE expressed per fat-free mass (86 ± 1 vs. 78 ± 2 J·kg fat-free mass−1·min−1, P < 0.01) were significantly higher in the HAART+LD+ than the HAART+LD− group. Rate of lipid oxidation was significantly higher in the HAART+LD+ than the HAART+LD− group. Total energy and fat intakes were significantly increased in the HAART+LD+ compared with the HAART+LD− group. These results imply that HAART-associated lipodystrophy is associated with increased REE and lipid oxidation and with increased caloric and fat intake.


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