Physiological Effects of Weight Cycling in Female Lightweight Rowers

1993 ◽  
Vol 18 (3) ◽  
pp. 291-303 ◽  
Author(s):  
Linda J. McCargar ◽  
Deanna Simmons ◽  
Neil Craton ◽  
Jack E. Taunton ◽  
C. Laird Birmingham

Repeated cycles of weight loss and regain are referred to as weight cycling. It is a practice of many athletes who must achieve a low body weight. The purpose of this study was to determine whether a history of weight cycling results in sustained metabolic changes. Healthy female rowers with a history of dieting and weight fluctuation (n = 7) were compared to a control group of rowers who had never dieted (n = 7). Anthropometric and metabolic measurements were done at pre-, peak, and off-season during a 1-year period. At peak season the weight cyclers restricted their food intake and lost 4.2 ± 1.8 kg, and subsequently regained 4.0 ± 2.1 kg in the off-season. This was different from the controls (p =.003), who maintained a stable body weight at all times. No other group differences were observed. Resting metabolic rate (RMR) and triiodothyronine (T3) changed with time (p =.001, p =.000, respectively) in both groups, which appeared to reflect changes in fat free mass (FFM), not body weight. Long-term metabolic changes were not observed in these athletes. Key words: weight cycling, metabolic rate, body composition, rowers

2017 ◽  
Vol 72 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Seyedeh Forough Sajjadi ◽  
Khadijeh Mirzaei ◽  
Leila Khorrami-Nezhad ◽  
Zhila Maghbooli ◽  
Seyed Ali Keshavarz

Background: Resting metabolic rate (RMR) used to prognosticate and measure the amount of energy required. Vitamin D is known as a new predictor of RMR. The aim of this study is to investigate the relationship between vitamin D effects on RMR in connection with the vitamin D receptor (VDR) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) gene expression. Methods: We enrolled 298 overweight and obese adults in this cross-sectional study. Body mass index (BMI), fat mass, fat-free mass, insulin level, visceral fat, and vitamin D status were assessed. RMR was measured by means of indirect calorimetry. The real-time polymerase chain reaction using specific primer pairs for VDR and PGC-1α was performed. Results: There were significant differences in terms of fat free mass, fat percentage, insulin levels, RMR/kg body weight, and RMR/BMI, VDR, and PGC-1α among participants were categorized based on the vitamin D status. But after using general linear model for adjusting, all significant results missed their effectiveness except RMR/kg body weight and VDR. Linear regression analysis used to show the mediatory role of VDR and PGC-1α on the RMR/kg body weight and vitamin D status relationship. Our results showed that VDR had a mediatory effect on the relationship between RMR/kg body weight and vitamin D status (β = 0.38, 95% CI –0.48 to 1.60; β = –1.24, 95% CI –5.36 to 1.70). However, PGC-1α did not affect the relationship between RMR/kg body weight and vitamin D status (β = 0.50, 95% CI = –0.02 to 3.42; β = 0.59, 95% CI 0.14–3.90). Conclusion: Our study showed the mediatory effect of VDR gene expression in the association of 25(OH)2D plasma levels and resting metabolic rate among obese individuals.


2020 ◽  
Author(s):  
Seyedeh Forough Sajjadi ◽  
Atieh Mirzababaei ◽  
nasim Ghodoosi ◽  
Sara Pooyan ◽  
Hana Arghavani ◽  
...  

Abstract Objective Resting metabolic rate (RMR) accounts for most of the daily energy expenditure. The low-carb diet attenuates decreases in RMR. This study aims to investigate the relationship between a low-carb diet and resting metabolic rate status. Methods We enrolled 304 overweight and obese women in this cross-sectional study. BMI, fat mass, fat-free mass, visceral fat, insulin level were assessed. RMR was measured using indirect calorimetry. A low carbohydrate diet score was measured using a validated semi-quantitative food frequency questionnaire (FFQ). Results Our results showed no relationship between LCDS and DNR even after adjust for confounders (Inc. RMR: OR: 0.97; 95% CI: 0.92–1.01, P = 0.20; Dec. RMR: OR: 0.97; 95% CI: 0.94-1.00, P = 0.14). Some components of LCDS had significant differences with DNR, such as carbohydrate and Dec. RMR in adjusted model (OR: 1.62; 95% CI: 0.98–1.37, P = 0.08), MUFA and Dec. RMR in adjusted model (OR: 0.48; 95% CI: 0.21–1.10, P = 0.08) and refined grain and Inc. RMR in crude model (OR: 0.87; 95% CI: 0.77–0.99, P = 0.04). Conclusion Our study showed that there is no association between a low-carb diet and RMR status but carbohydrate, MUFA, and refined grain had a significant relationship.


Nutrients ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 3394
Author(s):  
Sarah A. Purcell ◽  
Ryan J. Marker ◽  
Marc-Andre Cornier ◽  
Edward L. Melanson

Many breast cancer survivors (BCS) gain fat mass and lose fat-free mass during treatment (chemotherapy, radiation, surgery) and estrogen suppression therapy, which increases the risk of developing comorbidities. Whether these body composition alterations are a result of changes in dietary intake, energy expenditure, or both is unclear. Thus, we reviewed studies that have measured components of energy balance in BCS who have completed treatment. Longitudinal studies suggest that BCS reduce self-reported energy intake and increase fruit and vegetable consumption. Although some evidence suggests that resting metabolic rate is higher in BCS than in age-matched controls, no study has measured total daily energy expenditure (TDEE) in this population. Whether physical activity levels are altered in BCS is unclear, but evidence suggests that light-intensity physical activity is lower in BCS compared to age-matched controls. We also discuss the mechanisms through which estrogen suppression may impact energy balance and develop a theoretical framework of dietary intake and TDEE interactions in BCS. Preclinical and human experimental studies indicate that estrogen suppression likely elicits increased energy intake and decreased TDEE, although this has not been systematically investigated in BCS specifically. Estrogen suppression may modulate energy balance via alterations in appetite, fat-free mass, resting metabolic rate, and physical activity. There are several potential areas for future mechanistic energetic research in BCS (e.g., characterizing predictors of intervention response, appetite, dynamic changes in energy balance, and differences in cancer sub-types) that would ultimately support the development of more targeted and personalized behavioral interventions.


1990 ◽  
Vol 259 (2) ◽  
pp. E233-E238 ◽  
Author(s):  
N. K. Fukagawa ◽  
L. G. Bandini ◽  
J. B. Young

The relationship between fat-free mass (FFM) and resting metabolic rate (RMR) was compared in young men (n = 24; age 18-33 yr), old men (n = 24; 69-89 yr), and old women (n = 20; 67-75 yr). Body composition was assessed using anthropometry, bioelectrical impedance analysis (BIA), and isotope dilution with 18O-labeled water. RMR was measured at least twice using an open-circuit indirect calorimetry system with a ventilated hood. The results indicate that the different methods for assessing body composition vary substantially and should not be used interchangeably. Anthropometry was not adequate to assess group differences in body fatness, although skinfold measures may be appropriate for within-group comparisons. BIA correlated well with the isotope-dilution technique and may be a useful measure of FFM. Finally, RMR was lower in the old men than the young (1.04 +/- 0.02 vs. 1.24 +/- 0.03 kcal/min, P less than 0.001) and remained lower even when adjusted for FFM estimated by isotope dilution (P less than 0.001). RMR in the women was also lower (0.84 +/- 0.02 kcal/min), but in contrast to the difference between young and old men, RMR adjusted for FFM did not differ (P = 0.16) between old men and women. Therefore, it is clear that differences in FFM cannot fully account for the lower RMR in the old, suggesting that aging is associated with an alteration in tissue energy metabolism.


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.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Renata G. Duft ◽  
Alex Castro ◽  
Ivan L. P. Bonfante ◽  
Wendell A. Lopes ◽  
Larissa R. da Silva ◽  
...  

Abstract Exercise training and a healthy diet are the main non-pharmacological strategies for treating chronic conditions, such as obesity and insulin resistance (IR), in adolescents. However, the isolated metabolic changes caused by exercise training without dietary intervention have not yet been established. We investigated how combined training (CT) without dietary intervention altered the concentrations of serum metabolites, biochemical, anthropometric and functional parameters in overweight and obese adolescents. Thirty-seven adolescents (14.6 ± 1.05 years), of both sexes, were randomly assigned to the control group (CG, n = 19) or the training group (TG, n = 18). The CT was composed by resistance training and aerobic training performed in the same session (~ 60 min), three times a week, for 12 weeks. All assessments were performed pre and post-intervention. Metabolomics analyses were conducted using nuclear magnetic resonance spectroscopy (1H NMR) in a 600 MHz spectrometer. There was a decrease in body weight (BW), body mass index (BMI), waist circumference (WC), % body fat (%BF), fasting glucose, insulin levels, and insulin resistance (IR), by HOMA-IR, in the TG. An increase in fat-free mass (FFM) was also observed in the CG. The metabolic changes were given mainly by changes in the levels of metabolites 2-oxoisocaproate (↓TG), 3-hydroxyisobutyrate (↑CG and ↓TG), glucose (↓TG), glutamine (↓CG and ↑TG) and pyruvate (↓TG). These findings demonstrate the positive effects of CT program without dietary intervention on metabolomic profile, body composition, biochemical markers, and glucose metabolism in overweight and obese adolescents.


Author(s):  
Heidi K. Byrne ◽  
Jack H. Wilmore

The present study was designed to investigate the effects of exercise training on resting metabolic rate (RMR) in moderately obese women. It was hypothesized that exercise training would increase resting metabolic rate. Nineteen previously sedentary, moderately obese women (age = 38.0 ± 0.9 years, percent body fat = 37.5 ± 0.8) trained for 20 weeks using either resistance training (RT) or a combination of resistance training arid walking (RT/W). The high intensity resistance training program was designed to increase strength and fat-free mass and the walking program to increase aerobic capacity. There was also a non-exercising control group (C) of 9 subjects in this study. Fat-free mass was significantly increased in both the RT (+1.90 kg) and RT/W (+1.90 kg) groups as a result of the training program. No group showed significant changes in fat mass or relative body fat from pre- to post-training. Aerobic capacity was slightly, though significantly, increased in the RT/W group only. The RT group showed a significant increase (+44 kcal · day−1), while the RT/W group showed a significant decrease (-53 kcal · day−1) in resting metabolic rate post-training. RT can potentiate an increase in RMR through an increase in fat-free mass, and the decrease in RMR in the RT/W group may have been a result of heat acclimation from the walk training.


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