Interactive Effects of an Isocaloric High-protein Diet and Resistance Exercise in Untrained Overweight Young Men
Condition: Overweight; Obesity
MeSH terms: Overweight
Study type: Interventional

Summary: 
      Background: The interactive effects of resistance training and dietary protein on hormonal
      responses in overweight or obese adults are not clear and remain controversial. Investigators
      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
      overweight healthy young men.

      Methodology: Investigators randomized 18 healthy young males to a standard diet (ST group) or
      an isocaloric high protein diet (HP group). Subjects in both groups participated in a 12
      week-resistance exercise program. Investigators 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.
    

Detailed description: 
      Background: The interactive effects of resistance training and dietary protein on hormonal
      responses in overweight or obese adults are not clear and remain controversial. Investigators
      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
      overweight healthy young men.

      Methodology: Investigators randomized 18 healthy young males to a standard diet (ST group) or
      an isocaloric high protein diet (HP group). They have not participated in any
      weight-management program during the previous 6 months. An open-label design will be used. At
      enrolment, participants will randomly assign to one of two groups: a control group with a
      standard diet (total calories 2,400 kcal/day, 60% carbohydrate, 15% protein and 25% fat; ST
      group) and an interventional group with an isocaloric high protein diet (total calories 2,400
      kcal/day, 55% carbohydrate, 30% protein and 15% fat; HP group). Participants in both groups
      take part in a scheduled resistance exercise training program. Participants does not take
      part in any other resistance training program or competitive sport over the study duration.
      At the start of the study, participants will be instructed to maintain their assigned diet
      throughout the study period. This will be assessed using a food frequency questionnaire (FFQ)
      with a 24-h recall after 12 weeks. Participants are presented with two-dimensional food
      pictures of the actual size of portions on a computer by a single trained dietitian to
      minimize interviewer bias. Medium are defined as the portion sizes shown, small are
      approximately half the medium portion size, and large are one-and-a-half times the medium
      portion size.

      Exercise Protocol All participants will be under supervision during participation in the
      progressive supervised resistance exercise-training program. They participate in an onsite
      supervised protocol for 12 weeks (6 days per week). Exercise duration will be increased
      gradually, from 50 min at week 1 to 80 min at week 12, including warm-up for 20 min and
      cool-down periods for 10 min by carrying out gentle stretching exercises of the upper and
      lower limbs. A one repetition maximum (1-RM) is the maximum weight that can be lifted for one
      complete repetition of the movement. For each participant, the RM will be calculated for a
      particular muscle group. Each movement will be carried out at 60-80% of his 1-RM. Resistance
      will be increased slowly by three steps; step 1 (60-70% of his 1-RM for week 1-4), step 2
      (65-75% of his 1-RM for week 5-8) and step 3 (70-80% of his 1-RM for week 9-12).

      Baseline and Follow-up Measurements Height and bodyweight are measured using a digital scale
      with the examinee wearing a light gown, but no shoes. Body mass index (BMI) are calculated as
      weight (kg) divided by height squared (m2). The percentage body fat and total fat mass are
      measured by bioelectric impedance analysis (Inbody 3.0; Biospace Co., Ltd., Seoul, Korea), a
      sensitive test for quantification of changes in lean and fat mass in vivo and for assessment
      of regional fat distribution. A mercury sphygmomanometer are used for measurement of blood
      pressure (BP) of each participant, in the sitting position, after a 10-min resting period.
      Two readings each for the systolic and diastolic Bps are recorded at 3-min intervals, and the
      average of each measurement are included in our analysis.

      Blood samples are obtained preprandially at 0.800 hours from each participant's antecubital
      vein after a 12-h fast, and are used for determination of plasma glucose, insulin, lipid
      profile, total ghrelin, GH, insulin-like growth factor-1 (IGF-1), testosterone and cortisol.
      Blood samples are obtained at baseline (prerandomization) and 12 weeks after randomization.
    

Intervention name(s): High protein diet, Resistance exercise; Standard diet, Resistance exercise
Intervention type(s): Behavioral; Behavioral
Intervention description(s): The progressive supervised resistance exercise training program was performed by all participants under supervision. They participated in an onsite supervised protocol for 12 weeks (six days per week); weeks 1-4 (Monday - pectorialis major, Tuesday - latissimus dorsi, Wednesday - femoral, Thursday - deltoid, Friday - biceps brachii, Saturday - triceps brachii muscle), weeks 5-8 (Monday and Friday- pectorialis major and triceps brachii, Tuesday and Saturday - latissimus dorsi and biceps brachii, Wednesday and Monday - femoral, Thursday and Tuesday - deltoid muscle), weeks 9-12 (Monday and Thursday - pectorialis major and latissimus dorsi, Tuesday and Friday - femoral and deltoid, Wednesday and Saturday - triceps brachii and biceps brachii muscle).; The progressive supervised resistance exercise training program was performed by all participants under supervision. They participated in an onsite supervised protocol for 12 weeks (six days per week); weeks 1-4 (Monday - pectorialis major, Tuesday - latissimus dorsi, Wednesday - femoral, Thursday - deltoid, Friday - biceps brachii, Saturday - triceps brachii muscle), weeks 5-8 (Monday and Friday- pectorialis major and triceps brachii, Tuesday and Saturday - latissimus dorsi and biceps brachii, Wednesday and Monday - femoral, Thursday and Tuesday - deltoid muscle), weeks 9-12 (Monday and Thursday - pectorialis major and latissimus dorsi, Tuesday and Friday - femoral and deltoid, Wednesday and Saturday - triceps brachii and biceps brachii muscle)
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: protein; resistance exercise ghrelin; overweight