Effect of Nutritional Intervention and Olive Oil in Severe Obesity
Condition: Severe Obesity
MeSH terms: Obesity; Obesity, Morbid
Study type: Interventional

Summary: 
      Obesity is a worldwide epidemic with increasing prevalence, specially severe obesity (Body
      Mass Index (BMI) ≥ 35 kg/m2). It is a multifactorial disease that involves genetic and
      environmental factors that lead to increased mortality from cardiovascular disease, diabetes,
      cancer, among others and impairs life quality. Most research on severe obesity focuses on
      surgical alternatives and their results, thus this clinical trial aims to evaluate the effect
      of a non-pharmacological approach based on nutritional intervention and supplementation with
      a functional food, the olive oil. It will analyze the effectiveness of interventions on:
      weight loss, improvements on body composition and inflammatory profile (TNF-alfa,
      interleucins 1, 6 and 10, adiponectin), insulin resistance and serum lipids control, changing
      eating habits and physical activity practice, modification on bone mineral density and
      sarcopenia, and reduction of cardiovascular risk and other diseases. Also, it will be
      investigated the influence of polymorphisms (Pro12Ala of PPAR-γ gene, -174G>C of IL6 gene e
      Trp64Arg of ADRB3 gene) on nutritional intervention effectiveness with and without olive oil.
      This research looks for improving severely obese patient's care and contributing to effective
      results by reducing costs and risk treatment. The investigators believe that this
      informations will contribute significantly to the scientific field, expanding the knowledge
      about severe obesity.
    

Detailed description: 
      After enrollment, patients undergo a diagnostic phase (baseline) with nutritional,
      anthropometric and body composition assessment (multifrequency bioelectrical impedance
      analysis and dual X-ray absorptiometry); investigation of clinical history; collecting blood
      samples; carotid artery intima-media thickness, heart rate variability and accelerometry
      assessments; and application of validated questionnaires to evaluate secondary outcomes.
      Patients will be randomized into three different treatment groups. Randomization will be
      stratified according to Body Mass Index (BMI) (BMI between 35 and 39,99 kg/m2 and BMI ≥ 40
      kg/m2), allocation ratio 1:1:1 and parallel intervention. Then, trained nutritionists will
      deliver the intervention according to the patient group and they will be followed-up for 12
      weeks, with visits each 4 weeks.

      Interventions will be provided as follow:

      Olive oil group: in order to evaluate the effect of only the extra virgin olive oil on
      primary and secondary outcomes, patients will be instructed to maintain habitual food
      consumption and consume 52 mL of extra virgin olive oil daily (4 sachets per day, 2 at lunch
      and 2 at dinner).

      Nutritional intervention group: patients assigned to this group will receive nutritional
      intervention consisting of prescription of individualized food plan to reduce 5 to 10% of
      initial body weight, nutritional counseling for comorbidities and promoting healthy eating
      habits and physical activity. Resting Energy Expenditure (REE) will be calculated according
      to Horie-Waitzberg & Gonzalez equation developed for severe obese individual using current
      weight and lean body mass (Horie et al., 2011). Total energy expenditure (TEE) will be
      calculated multiplying REE by activity factor recommended by Institute of Medicine (Trumbo et
      al., 2005) and thermic effect of food (Hill, Wyat, Peters, 2012). Total energy value (TEV) of
      diet will be determined reducing 550 to 1100 kcal from TEE to reach 0.5 to 1.0 weekly weight
      reduction according to the patient's individual goal. Distribution of macronutrients will
      follow Dietary Reference Intake (DRI) recommendation: 45-65% of carbohydrates, 10-35% of
      proteins and 20-35% of lipids (Trumbo et al., 2002). Fat acids (FA) will be distributed as
      recommended by Sociedade Brasileira de Cardiologia (Sposito et al., 2007): ≤ 7% saturated FA,
      ≤ 20% monounsaturated FA and ≤ 7% polyunsaturated FA. Food plan prescription will distribute
      TEV in 4-6 meals. Motivation will be held to changing eating and lifestyle habits.

      Nutritional intervention plus olive oil: this group will receive conventional intervention
      plus supplementation of 52 mL of extra virgin olive oil daily (4 sachets per day, 2 at lunch
      and 2 at dinner).

      At the end of follow-up the same assessments performed at diagnostic phase will be held.

      To detect a reduction of 10 kg, with standard deviation of 30, which is in agreement with the
      study of Rodrigues e Silveira (2011), with a two-sided 5% significance level and a power of
      80%, a sample size of 50 patients per group will be necessary, given an anticipated dropout
      rate of 42,9%.

      This research will be conducted at a capital of center Brazil, at Unidade de Pesquisa Clínica
      of Hospital das Clínica/UFG, Faculty of Medicine/UFG.
    

Intervention name(s): Nutritional intervention; Nutritional intervention plus olive oil; Olive oil
Intervention type(s): Behavioral; Other; Dietary Supplement
Intervention description(s): Conventional treatment (Nutritional intervention) consists of prescription of individualized food plan to reduce 5 to 10% of initial body weight, nutritional counseling for comorbidities and promoting healthy eating habits and physical activity.; Nutritional intervention consists of prescription of individualized food plan to reduce 5 to 10% of initial body weight, nutritional counseling for comorbidities and promoting healthy eating habits and physical activity. Additionally, dietary supplementation with extra virgin olive oil (52 mL daily) will be held, divided in four (4) sachets per day, two (2) at lunch and two (2) at dinner.; Patients will be instructed to maintain habitual food consumption and consume 52 mL of extra virgin olive oil daily in four (4) sachets per day, two (2) at lunch and two (2) at dinner.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: nutritional management; olive oil; weight loss; body composition; nutrigenomics; polymorphisms; cardiovascular risk; sarcopenia; inflammation; food intake; sedentary lifestyle; patient adherence; bone density