Gene-Environment Interaction and Precision Nutrition on Adiposity, Glycemic, Lipids Changes, and Bone Health
Condition: Overweight and Obesity
MeSH terms: Obesity; Overweight
Study type: Interventional

Summary: 
      The purpose of this study is to test the interactions between the genes and diet
      interventions varying in macronutrient intake on glycemic, waist circumference, body weight,
      visceral fat and lipids changes. In the POUNDS LOST, all of the 811 participants DNA was
      extracted from the buffy coat fraction of centrifuged blood using the QIAmp blood kit
      (Qiagen, Chatsworth, CA). Single nucleotide polymorphisms were genotyped using the OpenArray™
      SNP genotyping system (BioTrove, Woburn, MA). The study is only accepting participants in the
      Boston, Massachusetts or Baton Rouge, Louisiana area. For further enrollment information in
      Boston or Baton Rouge, see Eligibility Criteria or Design Narrative.

      Besides, the investigators integrated novel pathway analyses in large cohorts and
      comprehensive genetic analyses on long-term weight loss and mechanisms in randomized diet
      intervention trials would provide very important evidence to unravel the etiology of obesity,
      and have significant public health and clinical implications. Establishing relationship
      between genetic variants and diets in determining weight change will help identify
      individuals at high risk for obesity especially when adherent to specific diet.
    

Detailed description: 
      The epidemic of obesity has become a major public health problem. Obesity is a multifactorial
      abnormality that has a genetic basis but requires environmental influences to manifest.
      Common-form obesity is underpinned by both environmental and genetic factors. Recent
      genome-wide association studies have identified several genes convincingly related to obesity
      risk. Testing gene-environment interaction is a relatively new field. Evidence from
      association studies and intervention trials continues to mount, indicating that genetic
      components may modify lifestyle effects on the development of obesity. However, these
      findings are at most preliminary. The interplay between genetic and environmental components
      may facilitate the choice of more effective and specific measures for obesity prevention
      based on personalized genetic make-up.

      The investigators aimed to examine whether the genetic variation affected glycemic, waist
      circumference, body weight, visceral fat and lipids changes in response to weight-loss
      dietary intervention varying in macronutrient intake (target percentages of energy derived
      from fat, protein, and carbohydrate in the 4 diets were as follows 20%, 15% and 65%; 20%,
      25%, and 55%; 40%, 15%, and 45%; and 40%, 25%, and 35%).

      The primary outcome is to test the interactions between the genes and diet interventions
      varying in macronutrient intake on body weight changes. The secondary outcome is to test the
      interactions between the genes and diet interventions varying in macronutrient intake on
      glycemic, waist circumference, visceral fat, and lipids changes. Understanding gene-diet
      interactions in relation to weight loss hold great promise for delivering more efficient
      prevention and treatment on obesity and related metabolic disorders.

      In addition, besides gene-diet interactions, the investigators will also conduct other
      precision nutrition analysis. These analyses include interactions between pretreatment
      factors with diet intervention adiposity traits, initial changes induced by diet intervention
      with various outcomes measured in POUNDS Lost, including body weight, waist circumference,
      body composition, ectopic fat, and bone health.
    

Intervention name(s): Preventing Overweight Using Novel Dietary Strategies
Intervention type(s): Other
Intervention description(s): The study tests the effectiveness for weight loss and weight maintenance of four diets differing in macronutrient composition: moderate in fat (40% energy) with two different protein levels (15% and 25%), and low in fat (20% energy), also with 15% and 25% protein levels.
Allocation: Randomized
Intervention model: Factorial Assignment
Masking: None (Open Label)
Primary purpose: Prevention