Metabolic and Bio-behavioral Effects of Following Recommendations in the Dietary Guidelines for Americans
Metabolic and Bio-behavioral Effects of Following Recommendations in the Dietary Guidelines for Americans
This study, at the Western Human Nutrition Research Center (WHNRC), will focus on whether or
 not achieving and maintaining a healthy body weight is the most important health promoting
 recommendation of the Dietary Guidelines for Americans (DGA).The investigators hypothesize
 that improvement in cardiometabolic risk factors resulting from eating a DGA style diet will
 be greater in people whose energy intake is restricted to result in weight loss compared to
 those who maintain their weight. The investigators further propose that during a state of
 energy restriction, a higher nutrient quality diet such as the DGA style diet pattern, will
 result in greater improvement in cardiometabolic risk factors compared to a typical American
 diet (TAD) pattern that tends to be lower nutrient quality (more energy-dense and less
 nutrient-rich.)
This will be a 32-week study including baseline testing (week 0), increased physical activity
 in all groups, pre-diet testing (week 5), an 8-week controlled feeding period, post-diet
 testing (week 14), a follow-up period of dietary education and observation, and end of study
 testing (week 32). During the 8 week feeding, participants will be randomly assigned one of
 the following diets:

 1. DGA Mediterranean diet pattern at sufficient energy level to maintain body weight
 (energy balance)

 2. DGA Mediterranean diet pattern at a moderately reduced energy level (negative energy
 balance)

 3. TAD diet pattern at a moderately reduced energy level (negative energy balance)

 In the follow-up phase, the investigators will evaluate how multiple factors may influence
 body weight management, including previous dietary exposure, as well as the role of cognitive
 function, executive function, genetics, habitual diet, physical activity, eating behavior,
 stress and stress responsivity, metabolic flexibility and gut microbiome.
Inclusion Criteria:

 -  Body Mass Index (BMI) 27-39.9 kg/m2 or 32-50% body fat percentage

 -  Willingness to have blood drawn

 -  The criteria listed above and at least one of the following: Fasting glucose ≥100
 mg/dL but <126 mg/dL or Fasting triglyceride ≥125 mg/dL or HDL-cholesterol ≤50 mg/dL
 or Blood Pressure (BP): Systolic BP ≥130 mmHg or Diastolic BP ≥85 mmHg or Hemoglobin
 A1C ≥ 5.7 and <6.5%

 Exclusion Criteria:

 -  Blood Pressure (BP): Systolic BP ≥140 mmHg or Diastolic BP ≥90 mmHg

 -  LDL cholesterol ≥190 mg/dL

 -  Triglycerides ≥500 mg/dL

 -  Current use of smoking or chewing tobacco, e-cigarettes, cigars, vaping, cannabis or
 other use of nicotine containing products (within the past 6 months)

 -  Current use of dietary supplements and/or unwillingness to cease intake of dietary
 supplements

 -  Vegan or vegetarian lifestyle or any other dietary restrictions that would interfere
 with consuming the intervention foods and beverages (including dietary intolerances,
 allergies and sensitivities)

 -  Unwillingness to consume intervention foods and beverages

 -  Engage in more than moderate drinking (> 1 drink serving per day) or binge drinking (4
 drinks within two hours).

 -  Unwillingness to cease alcohol intake as required for specific duration of the study

 -  Excessive intake of caffeine containing products (excessive defined as ≥ 400 mg/day)

 -  Unwillingness to refrain from caffeine intake on lab visit days.

 -  Intentional weight change of ≥5% of body weight within 6 months of entry into the
 study

 -  Diagnosis of disordered eating or eating disorder

 -  Recent diagnosis of any of the following or measurement on screening lab tests: Anemia
 (hemoglobin <11.7 g/dL) or abnormal liver or thyroid function (defined as liver
 enzymes that are >200% of upper limit (ALT upper limit is 43 U/L or Aspartate
 transaminase (AST) upper limit is 54 U/L) and thyroid function tests: Thyroxine (T4,
 free) <0.56 or >1.64 ng/dL; Thyroid-stimulating hormone (TSH) <0.35 or >5.6 μIU/mL).

 -  History of any of the following: Gastric bypass surgery, inflammatory bowel disease
 (IBD) or other GI conditions that would interfere with consuming the intervention
 foods, active cancer in the past three years excluding squamous or basal cell
 carcinomas of the skin that have been handled medically by local excision and other
 serious medical conditions

 -  Recent dental work or have conditions of the oral cavity that would interfere with
 consuming the intervention foods and beverages

 -  Taking any medication in the class of antipsychotics

 -  Long term use of antibiotics

 -  Taking any over the counter or prescribed medication for any of the following:
 Elevated lipids, elevated glucose, high blood pressure, weight loss or conditions that
 require corticosteroids (e.g. asthma, arthritis or eczema).

 -  Are pregnant, planning to become pregnant within the duration of the study or
 breastfeeding.