Obesity
Conditions
Brief summary
The purpose of this research is to test the effects of the Dietary and Physical Activity Guidelines for Americans on health and on eating and exercise behaviors.
Detailed description
The Dietary Guidelines for Americans (DGA), which include the Physical Activity Guidelines for Americans (PAGA), is the primary United States (U.S) government resource for weight control. The researchers propose that chronic, low grade inflammation (CLGI) limits weight control by acting upon physiological and behavioral factors that moderate weight control. Diet and exercise reduce CLGI and provide weight control, but no one has investigated the efficacy of the DGA and PAGA to reduce CLGI, whether reduced CLGI promotes greater weight control, and the moderating roles of physiological and behavioral factors on the association of reduced CLGI with weight control. To accomplish this, the researchers will conduct a 6-month trial in 224 obese adults; a 3-month controlled feeding trial with four dietary arms; 1) DGA with weight loss, 2) Western diet with weight loss,3) DGA diet weight maintenance, 4) Western diet weight maintenance. Each dietary arm will have PAGA-recommended exercise and non-exercise arms. Post-trial is a 3-month weight maintenance period. The primary outcome is change in C-reactive protein (CRP), a marker of CLGI. The results will inform the DGA and PAGA; thereby helping clinicians, public health workers, and policymakers to improve the health of Americans.
Interventions
OTHERDGA diet WL & exercise
Intake of DGA weight loss 8 day rotating menu & PAGA-recommended exercise
OTHERDGA diet WL & no exercise
Intake of DGA weight loss 8 day rotating menu & no exercise
OTHERDGA diet WM & exercise
Intake of DGA weight maintenance 8 day rotating menu & PAGA-recommended exercise
OTHERDGA diet WM & no exercise
Intake of DGA weight maintenance 8 day rotating menu & no exercise
OTHERWestern diet WL & exercise
Intake of Western-type weight loss 8 day rotating menu & PAGA-recommended exercise
OTHERWestern diet WL & no exercise
Intake of Western-type weight loss 8 day rotating menu & no exercise
OTHERWestern diet WM & exercise
Intake of Western-type weight maintenance 8 day rotating menu & PAGA-recommended exercise
OTHERWestern diet WM & no exercise
Intake of Western-type weight maintenance 8 day rotating menu & no exercise
Sponsors
USDA Grand Forks Human Nutrition Research Center
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
OTHER
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* Obese (BMI 30.0 kg/m2 - 350 lbs \[maximum weight for dual energy x-ray absorptiometry (DXA) machine\]) * No contraindications to participate in exercise * hs-CRP level ≥3.0 and ≤10.0 mg/L or two consecutive measures of \>10.0 mg/L measured two weeks apart * Access to high-speed internet
Exclusion criteria
* Taking chronic anti-inflammatory medications * Being pregnant, lactating, or planning to become pregnant * Diagnosed eating disorder * Taking weight loss medication * Smoking * Overt hypothyroidism * Cancer * Physical conditions that prevent safe exercise * Liking of \<3 out of 10 for all available physical activity modes * Currently exercising for more than 30 minutes per day \>3 days per week * Unwilling to continue with current exercise routine * Not willing to comply with all study requirements * Blood pressure greater than 140/90
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fat and carbohydrate oxidation | Weeks 0,12 | The effect of diet and exercise on carbohydrate and fat oxidation in response to meals and exercise as measured by whole-room calorimetry |
| Relative reinforcing value (RRV) of exercise | Weeks 0,12, 24 | The effect of achieving the DGA recommended amounts of exercise during weight loss and weight maintenance on relative reinforcing value of exercise compared to a sedentary activity alternative using a computer choice paradigm. For the computer choice paradigm subjects click the mouse button to play a simulated slot machine games to earn points toward being able to do a chosen physical activity, such as walking on a treadmill, or a sedentary activity (e.g., watching TV). |
| Change in C-reactive protein (CRP) | Weeks 0, 2, 4, 6, 8, 10, 12, 24 | The effect of diet and exercise on CRP |
| Relative reinforcing value (RRV) of energy-dense snack foods | Weeks 0,12, 24 | The effect of consuming a healthy DGA style or a Western style diet during weight loss and weight maintenance on the RRV of energy-dense snack food using a computer choice paradigm. For the computer choice paradigm subjects click the mouse button to play a simulated slot machine games to earn points toward receiving a portion of food or being able to do a non-food related sedentary activity (e.g., watching TV). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Inflammation | Weeks 0, 2, 4, 6, 8, 10, 12, 24 | The effect of diet and exercise on plasma pro-inflammatory cytokines (e.g., Il-6, MCP-1, TNF-alpha) and anti-inflammatory cytokines (e.g., IL-10, Soluble TNF receptor I and II) |
| Change in adipokines | Weeks 0, 2, 4, 6, 8, 10, 12, 24 | The effect of diet and exercise on plasma adipokines (e.g., adiponectin, resistin) |
| Change in myokines | Weeks 0, 2, 4, 6, 8, 10, 12, 24 | The effect of diet and exercise on plasma myokines (e.g., BDNF, Myostatin, FGF-21, Irisin) |
| Change in bile acids | Weeks 0, 2, 4, 6, 8, 10, 12, 24 | The effect of diet and exercise on plasma bile acids (i.e., glycocholic acid, glyco-CDCA, glyco-HDCA, hyocholic acid, hyodeoxycholic acid) |
| Change in weight control moderators | Weeks 0,12, 24 | Questionnaires (i.e., three-factor eating questionnaire, reward base eating, food attitudes and behavior survey) that when scored provide a single number will be used to determine the moderating effect of self efficacy, restraint and disinhibition maintaining diet and exercise changes |
| Change in humoral biomarkers of eating behavior | Weeks 0, 2, 4, 6, 8, 10, 12, 24 | The effect of diet and exercise on ghrelin, leptin, thyroid hormones, gut peptides, fatty acids |
| Gene expression profiles of glucose oxidation | Weeks 0, 2, 4, 6, 8, 10, 12, 24 | The effect of diet and exercise on gene expression profiles associated with glucose oxidation (i.e., hexokinase, phosphofructokinase, pyruvate dehydrogenase kinase 4, peroxisome proliferator-activated receptor alpha gene expression) |
| Gene expression profiles of fat oxidation | Weeks 0, 2, 4, 6, 8, 10, 12, 24 | The effect of diet and exercise on on gene expression profiles associated with fat oxidation (i.e., fatty acid translocase, fatty acid synthase, acetyl Co-A carboxylase 2, stearoyl Co-A desaturase gene expression) |
| Change in blood lipids | Weeks 0, 2, 4, 6, 8, 10, 12, 24 | The effect of diet and exercise on cholesterol, HDL, triglycerides |
| Food Cognitive Interference | Weeks 0, 12, 24 | The effect of diet and exercise on food cognitive interference, one of the three cognitive domains of executive function, using a computerized Food Stroop test. |
| Cognitive flexibility | Weeks 0, 12, 24 | The effect of diet and exercise on cognitive flexibility, one of the three cognitive domains of executive function, using a computerized Trail-Making test B/A. |
| Working memory | Weeks 0, 12, 24 | The effect of diet and exercise on cognitive flexibility, one of the three cognitive domains of executive function, using the Wisconsin Card Sorting Task. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Single nucleotide polymorphisms (SNP) | Weeks 0 | Correlation of SNPs associated with skeletal muscle, catecholamine, executive function and food and exercise reinforcement |
| micro RNA (miRNA) | Weeks 0, 12, 24 | Correlation of miRNAs associated with skeletal muscle, executive function and food and exercise reinforcement |
Outcome results
None listed