Egg Diet to Improve Metabolic Health and Function

Study Overview
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Brief Summary
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The purpose of this study is to determine the effects of change in diet quality (carbohydrate restriction versus fat restriction) on body composition, fat distribution, cardiometabolic risk factors, physical function, and quality of life in aging adults with obesity.

Detailed Description
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The purpose of this study is to determine the effects of change in diet quality (carbohydrate restriction versus fat restriction) on body composition, fat distribution, cardiometabolic risk factors, physical function, and quality of life in aging adults with obesity. Data from previous studies support the hypothesis that consumption of lower-CHO, higher-fat food sources rich in high-quality proteins and essential fatty acids, such as whole eggs, has beneficial effects on metabolic health. The study will test the hypothesis that a reduced CHO higher- fat, egg-rich diet induces selective depletion of total and abdominal adiposity, preserves lean mass, and reduces inflammation and oxidative stress. In turn, these favorable changes in body composition, fat distribution, and metabolic health will confer improvements in physical function in obese, aging adults. Results from this study will form an empirical basis for developing an easily implemented, non-pharmacologic treatment (i.e. change diet quality by incorporating more low carbohydrate, whole foods such as eggs) to prevent or reverse sarcopenia and other age-related diseases of metabolic origins.

Official Title
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Does an Egg-Rich Diet Improve Metabolic Health and Function in Obese Older Adults

Conditions
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Obesity

Intervention / Treatment
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* Other: Egg-based diet (EBD)
* Other: Carbohydrate-based diet (CBD)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: between 60-75 years of age, have a BMI ranging from 30-40 kg/m2, sedentary (<2h/wk of intentional exercise, and agree to maintain their level of activity throughout the study). Exclusion Criteria: those with uncontrolled diabetes, unwilling to eat the prescribed diets, recent weight change (+/- 10 lbs. in previous year), history of eating disorder, difficulty chewing and swallowing solid food, digestive diseases, cognitive impairment, uncontrolled blood pressure (systolic blood pressure > 159 or diastolic blood pressure >95 mm Hg), history of non-skin cancer in the last 5 years, cardiovascular disease event; severe pulmonary disease; renal failure; major liver dysfunction, current/recent smoker, use of estrogen or testosterone replacement therapy, current use of oral corticosteroids (>5 d/mth), using medications for treatment of psychosis or manic-depressive illness, and dependence on others for food procurement or preparation.

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Egg-based diet (EBD)<br>This arm will provide ≤25% energy from CHO, 25% energy from protein, and ≥50% energy from fat. EBD participants will be asked to consume ≥2 eggs per day along with other protein sources including meat, fish, pork, and poultry. Carbohydrate (CHO) sources will be primarily derived from leafy greens and non-starchy vegetables and CHO intake will be equally distributed across meals throughout the day. | Other: Egg-based diet (EBD)<br>* Participants will be asked to consume a carbohydrate-restricted diet including whole eggs for 8 weeks. Eggs will be provided.<br>|
| Placebo Comparator: Carbohydrate-based diet (CBD)<br>The CBD group will be asked to avoid whole egg consumption when possible during the 8 week intervention period. They will be counseled to consume a low fat diet with 55:25:20 %energy from CHO:protein:fat. This diet will place an emphasis on consuming lean meats, low fat dairy, whole grains, legumes, fruits and vegetables. | Other: Carbohydrate-based diet (CBD)<br>* Participants will be asked to consume a low fat, carbohydrate-based diet for 8 weeks. Breakfast food items will be provided.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in total fat mass as measured by dual-energy X-ray absorptiometry (DXA) |  | 8 weeks after baseline | 
| Changes in visceral adipose tissue as measured by magnetic resonance imaging (MRI) |  | 8 weeks after baseline | 
| Changes in total lean mass as measured by DXA |  | 8 weeks after baseline | 
| Changes in subcutaneous abdominal adipose tissue as measured by MRI |  | 8 weeks after baseline | 
| Changes in thigh intermuscular adipose tissue as measured by MRI |  | 8 weeks after baseline | 
| Changes in thigh skeletal muscle volume as measured by MRI |  | 8 weeks after baseline | 
| Changes in thigh subcutaneous adipose tissue as measured by MRI |  | 8 weeks after baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in pro-inflammatory markers, Interleukin (IL)-6 |  | 8 weeks after baseline | 
| Changes in pro-inflammatory marker, hsCRP |  | 8 weeks after baseline | 
| Changes in pro-inflammatory marker, Tumor Necrosis Factor (TNF)-α |  | 8 weeks after baseline | 
| Changes in metabolic hormone adiponectin |  | 8 weeks after baseline | 
| Changes in metabolic hormone leptin |  | 8 weeks after baseline | 
| Changes in metabolic hormone insulin |  | 8 weeks after baseline | 
| Changes in markers of oxidative stress : isoprostanes |  | 8 weeks after baseline | 
| Changes in markers of oxidative stress : protein carbonyls |  | 8 weeks after baseline | 
| Changes in markers of oxidative stress : total anti-oxidants |  | 8 weeks after baseline | 
| Changes in insulin sensitivity with euglycemic-hyperinsulinemic clamp |  | 8 weeks after baseline | 
| Changes in the lipid profile: triglycerides |  | 8 weeks after baseline | 
| Changes in the lipid profile: total cholesterol |  | 8 weeks after baseline | 
| Changes in the lipid profile: HDL-C |  | 8 weeks after baseline | 
| Changes in the lipid profile: LDL |  | 8 weeks after baseline | 
| Changes in physical function: Short Physical Performance Battery |  | 8 weeks after baseline | 
| Changes in physical function : muscle strength |  | 8 weeks after baseline | 
| Changes in quality of life (SF-36 Health Survey). |  | 8 weeks after baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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obesity, low carbohydrate diet, metabolism, body composition, visceral fat, older adults, insulin sensitivity