Interactive effects of an isocaloric high-protein diet and resistance exercise on body composition, ghrelin, and metabolic and hormonal parameters in untrained young men: A randomized clinical trial.
OBJECTIVE
The interactive effects of resistance training and dietary protein on hormonal responses in adults are not clear and remain controversial. We tested the effect of an isocaloric high-protein diet on body composition, ghrelin, and metabolic and hormonal parameters during a 12-week resistance training program in untrained healthy young men.


METHODS
We randomized 18 healthy young men to a standard diet (ST group) or an isocaloric high protein diet (HP group). Both groups participated in a 12-week resistance exercise program. We measured body composition, lipid profile, homeostatic model assessment of insulin resistance (HOMA-IR) indices, total ghrelin, and exercise-related hormones at baseline and 12 weeks.


RESULTS
In the HP group, lean body mass (LBM), total ghrelin, growth hormone, testosterone and cortisol levels showed an increase, whereas body fat percentage and HOMA-IR showed a decrease at 12 weeks, compared with baseline (P ≤ 0.05). In the ST group, no changes in these parameters were observed during the 12-week period. During the 12-week period, significant differences in the pattern of change of LBM (P = 0.032), total ghrelin (P = 0.037), HOMA-IR (P = 0.040) and high-density lipoprotein cholesterol (P = 0.011) over time were observed between the groups.


CONCLUSIONS
The findings of the present study suggest that an isocaloric high-protein diet can ameliorate body composition, metabolic profiles and energy metabolism during a 12-week scheduled resistance training program in untrained healthy young men. This trial was registered with ClinicalTrials.gov (no. NCT01714700).
Department of Family Medicine Pusan National University School of Medicine Yangsan Korea.
Hyun Ho
HH
Kim
Department of Family Medicine Pusan National University School of Medicine Yangsan Korea.
Yun Jin
YJ
Kim
Medical Education Unit and Medical Research Institute Pusan National University School of Medicine Yangsan Korea ; Family Medicine Clinic and Research Institute of Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital Yangsan Korea.
Sang Yeoup
SY
Lee
Family Medicine Clinic and Research Institute of Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital Yangsan Korea.
Dong Wook
DW
Jeong
Department of Family Medicine Pusan National University School of Medicine Yangsan Korea.
Jeong Gyu
JG
Lee
Department of Family Medicine Pusan National University School of Medicine Yangsan Korea.
Yu Hyone
YH
Yi
Department of Family Medicine Pusan National University School of Medicine Yangsan Korea ; Family Medicine Clinic and Research Institute of Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital Yangsan Korea.
Young Hye
YH
Cho
Department of Family Medicine Pusan National University School of Medicine Yangsan Korea ; Family Medicine Clinic and Research Institute of Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital Yangsan Korea.
Eun Jung
EJ
Choi
Department of Physical Education Kyungnam University College of Education Masan Korea.
Hyun Jun
HJ
Kim
Hormone; Protein; Resistance exercise