The Effects of Intensive Weight Reduction on Body Composition and Serum Hormones in Female Fitness Competitors

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Hulmi , J , Isola , V , Suonpaa , M , Jarvinen , N J , Kokkonen , M , Wennerstrom , A , Nyman , K , Perola , M , Ahtiainen , J P & Hakkinen , K 2017 , ' The Effects of Intensive Weight Reduction on Body Composition and Serum Hormones in Female Fitness Competitors ' , Frontiers in Physiology , vol. 7 , 689 . https://doi.org/10.3389/fphys.2016.00689

Title: The Effects of Intensive Weight Reduction on Body Composition and Serum Hormones in Female Fitness Competitors
Author: Hulmi, Juha; Isola, Ville; Suonpaa, Marianna; Jarvinen, Neea J.; Kokkonen, Marja; Wennerstrom, Annika; Nyman, Kai; Perola, Markus; Ahtiainen, Juha P.; Hakkinen, Keijo
Contributor: University of Helsinki, Department of Physiology
University of Helsinki, Institute for Molecular Medicine Finland
University of Helsinki, Institute for Molecular Medicine Finland
Date: 2017-01-10
Language: eng
Number of pages: 16
Belongs to series: Frontiers in Physiology
ISSN: 1664-042X
URI: http://hdl.handle.net/10138/174553
Abstract: Worries about the potential negative consequences of popular fat loss regimens for aesthetic purposes in normal weight females have been surfacing in the media. However, longitudinal studies investigating these kinds of diets are lacking. The purpose of the present study was to investigate the effects of a 4-month fat-loss diet in normal weight females competing in fitness-sport. In total 50 participants finished the study with 27 females (27.2 +/- 4.1 years) dieting for a competition and 23 (27.7 +/- 3.7 years) acting as weight-stable controls. The energy deficit of the diet group was achieved by reducing carbohydrate intake and increasing aerobic exercise while maintaining a high level of protein intake and resistance training in addition to moderate fat intake. The diet led to a similar to 12% decrease in body weight (P <0.001) and a similar to 3550% decrease in fat mass (DXA, bioimpedance, skinfolds, P <0.001) whereas the control group maintained their body and fat mass (diet x group interaction P <0.001). A small decrease in lean mass (bioimpedance and skinfolds) and in vastus lateralis muscle cross-sectional area (ultrasound) were observed in diet (P <0.05), whereas other results were unaltered (DXA: lean mass, ultrasound: triceps brachii thickness). The hormonal system was altered during the diet with decreased serum concentrations of leptin, triiodothyronine (T3), testosterone (P <0.001), and estradiol (P <0.01) coinciding with an increased incidence of menstrual irregularities (P <0.05). Body weight and all hormones except T3 and testosterone returned to baseline during a 34 month recovery period including increased energy intake and decreased levels aerobic exercise. This study shows for the first time that most of the hormonal changes after a 3550% decrease in body fat in previously normal-weight females can recover within 34 months of increased energy intake.
Subject: fat loss
exercise
nutrition
fitness
body composition
sex hormones
thyroid hormones
BODYBUILDING CONTEST PREPARATION
INCREASED PROTEIN-INTAKE
IOC MEDICAL COMMISSION
RESEARCH WORKING GROUP
LEAN MASS GAIN
ANOREXIA-NERVOSA
ENERGY DEFICIT
METABOLIC ADAPTATION
DIETARY-PROTEIN
ADIPOSE-TISSUE
1184 Genetics, developmental biology, physiology
3111 Biomedicine
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