Low Carbohydrates in Obese Adolescents
Condition: Obesity
MeSH terms: Obesity
Study type: Interventional

Summary: 
      A three arms open,randomized interventional study in order to compare the impact of low
      carbohydrate diets with different protein and fat ratios versus a standard balanced diet on
      BMI and metabolic parameters in obese adolescents.

      55 obese adolescents (12-18y, BMI > 95th percentile) were randomly allocated to one of three
      12-weeks diet regimens: low-carbohydrate low-fat, low-carbohydrate high-fat or balanced
      low-fat diet, followed by 9-months follow-up. Weight, Height, waist circumference, lipid
      profile, glucose, insulin, liver enzymes, renal functions, C-reactive protein, leptin,
      ghrelin and resting energy expenditure were measured in the morning after over-night fast at
      baseline, during the 12-weeks of intervention and after 9-months of follow-up.
    

Detailed description: 
      A three arms open,randomized interventional study in order to compare the impact of low
      carbohydrate diets with different protein and fat ratios versus a standard balanced diet on
      BMI and metabolic parameters in obese adolescents.

      Study design:

      The study included 12 weeks of intervention followed by 9 months of follow up, between March
      2005 to February 2006. Participants were randomly allocated to one of three diet groups.

      Group 1: Low carbohydrate, low fat, protein rich diet containing 1200 kcal a day, 60-gr
      carbohydrates (20%), 40-gr fat (30%), 150-gr protein (50%).

      Group 2: Low carbohydrate fat rich diet containing 1200 kcal a day, 60-gr carbohydrates
      (20%), 80-gr fat (60%), 60-gr protein (20%).

      Group 3: A balanced low fat diet containing 1200 kcal a day, 150 - 180-gr carbohydrates (50 -
      60%), 40-gr fat (30%), 60-gr protein (20%).

      All participant received menus and detailed instruction according to their group.

      During the intervention participant attended weekly sessions with a dietitian and a
      psychologist and a tests and measures scheduled for each time point were performed (see
      Measures section). In some sessions the participants were requested to fill-out self reports
      food dairies. All received general recommendations to exercise physical activity.

      At the end of the intervention period (12th week), all participants were given instruction
      for a balanced maintenance diet for the following year.

      measures: Anthropometric assessment (weight,height, waist circumference) included baseline
      and weekly measurement during the 12- week intervention, and thereafter every three months
      for 9-months of follow-up. Body composition was evaluated at baseline and after the 12- week
      intervention, after overnight fasting by bioimpedance analysis (BIA). Resting energy
      expenditure (REE) was assessed at baseline and after the 12- week intervention, in the
      morning after overnight fasting by means of indirect calorimetry. Urine was collected every
      week during the intervention period for assay of ketone and protein level. Fasting blood
      tests were preformed at baseline, weeks 7 and 12, and at the end of the follow-up to measure
      the following parameters: total cholesterol, Low Density Lipoprotein (LDL), HDL cholesterol,
      triglycerides, glucose, insulin, blood urea nitrogen, creatinine, total protein, liver
      enzymes (AST, ALT, GGT ),renal functions (urea, creatinine, electrolytes, uric acid),
      electrolyte level, Insulin like growth factor (IGF1), haemoglobin, C-reactive protein (CRP),
      TSH, free T4, iron, vitamin B12, folic acid ,leptin ,and ghrelin.
    

Intervention name(s): dietary intervention
Intervention type(s): Behavioral
Intervention description(s): 12 weeks of dietary intervention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Adolescent obesity,; low carbohydrate diets; metabolic risk factors; BMI