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DIETFITS Study (Diet Intervention Examining the Factors Interacting With Treatment Success
Not Recruiting
Trial ID: NCT01826591
Purpose
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.
Official Title
Do Insulin Secretion or Genotype Pattern Predict Low Fat vs Low Carb Weight Loss Success?
Stanford Investigator(s)
Eligibility
Inclusion Criteria:
- 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
Exclusion Criteria:
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
Intervention(s):
behavioral: Mobile App
behavioral: Low-Carbohydrate Diet
behavioral: Low-Fat Diet
Not Recruiting
Contact Information
Stanford University
School of Medicine
300 Pasteur Drive
Stanford,
CA
94305
Antonella Dewell, MS, RD
650-736-8577