DIETFITS Study (Diet Intervention Examining the Factors Interacting With Treatment Success
Trial ID or NCT#
Genomics research is advancing rapidly, and links between genes and obesity continue to be discovered and better defined. A growing number of single nucleotide polymorphisms (SNPs) in multiple genes have been shown to alter an individual's response to dietary macronutrient composition. Based on prior genetic studies evaluating the body's physiological responses to dietary carbohydrates or fats, the investigators identified multi-locus genotype patterns with SNPs from three genes (FABP2, PPARG, and ADRB2): a low carbohydrate-responsive genotype (LCG) and a low fat-responsive genotype (LFG). In a preliminary, retrospective study (using the A TO Z weight loss study data), the investigators observed a 3-fold difference in 12-month weight loss for initially overweight women who were determined to have been appropriately matched vs. mismatched to a low carbohydrate (Low Carb) or low fat (Low Fat) diet based on their multi-locus genotype pattern. The primary objective of this study is to confirm and expand on the preliminary results and determine if weight loss success can be increased if the dietary approach (Low Carb vs. Low Fat) is appropriately matched to an individual' s genetic predisposition (Low Carb Genotype vs. Low Fat Genotype) toward those diets.
Do Insulin Secretion or Genotype Pattern Predict Low Fat vs Low Carb Weight Loss Success?
- - Age: > 18 years of age - Women: Pre-menopausal (self-report) and <50 years of age - Men: <50 years of age - BMI (body mass index): 27-40 kg/m2 (need to lose >10% body weight to achieve healthy BMI) - Body weight stable for the last two months, and not actively on a weight loss plan - No plans to move from the area over the next two years - Available and able to participate in the evaluations and intervention for the study period - Willing to accept random assignment - To enhance study generalizability, people on medications not noted below as specific exclusions can - participate if they have been stable on such medications for at least three months - Ability and willingness to give written informed - No known active psychiatric illness
- Subjects with the following conditions will be excluded (determined by self-report): - Pregnant, lactating, within 6 months post-partum, or planning to become pregnant in the next 2 years - Diabetes (type 1 and 2) or history of gestational diabetes or on hypoglycemic medications for any other indication - Prevalent diseases: Malabsorption, renal or liver disease, active neoplasms, recent myocardial infarction (<6 months)(patient self-report and, if available, review of labs from primary care provider) - Smokers (because of effect on weight and lipids) - History of serious arrhythmias, or cerebrovascular disease - Uncontrolled hyper- or hypothyroidism (TSH not within normal limits) - Medications: Lipid lowering, antihypertensive medications, and those known to affect weight/energy expenditure - Excessive alcohol intake (self-reported, >3 drinks/day) - Musculoskeletal disorders precluding regular physical activity - Unable to follow either of the two study diets for reasons of food allergies or other (e.g., vegan) - Currently under psychiatric care, or taking psychiatric medications - Inability to communicate effectively with study personnel
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Antonella Dewell, MS, RD