Effect of Skipping Breakfast on Metabolic Function

Study Overview
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Brief Summary
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The purpose of this study is to test the hypothesis that the disruption of the normal (three meals a day) eating pattern and prolonged overnight fasting caused by skipping breakfast: i) alters the expression of specific clock genes and clock gene targets involved in regulating adipose tissue lipolysis (breakdown or destruction); ii) increases basal adipose tissue lipolytic (breakdown) activity and plasma free fatty acid (FFA) concentrations; iii) reduces skeletal muscle insulin sensitivity; and iv) increases daylong plasma glucose, FFA, and insulin concentrations. The investigator will do this by studying healthy, lean persons either randomized to consume either 3 standard meals per day or omit breakfast and consume 2 meals per day without changing daily calorie intake (skipping breakfast group).

Official Title
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Effect of Skipping Breakfast on Metabolic Function

Conditions
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Skipping Breakfast, Circadian Rhythms

Intervention / Treatment
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* Other: 3 standard meals/day
* Other: 2 meals/day (omit breakfast)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Males & females 18-55 years old BMI between 18.5 - 29.9 kg/m² Sleeps >7 hours/night Normally consume 3 meals/day, including breakfast Exclusion Criteria: Pregnancy, lactating or breastfeeding Diabetes Sleep disorders Significant organ dysfunction Shift or nighttime workers Smokers Breakfast skippers People who regularly sleep <7 hours/night Consume excess amounts of alcohol Medications that could alter the results of this study

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 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: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Control<br>Subjects randomized to this group will consume 3 standard meals/day during the 2 week intervention period of the study. | Other: 3 standard meals/day<br> <br> |
| Experimental: Breakfast skipping<br>Subjects randomized to this group will consume 2 meals/day (omit breakfast - with caloric intake equal to consuming 3 meals/day) during the 2 week intervention period of the study. | Other: 2 meals/day (omit breakfast)<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Determine the effect of skipping breakfast on basal adipose tissue lipolytic activity and skeletal muscle insulin sensitivity | Hyperinsulinemic-euglycemic clamp procedure in conjunction with stable isotopically labeled trace infusions will be conducted before and after the diet intervention to asses the changes on basal adipose tissue lipolytic activity and skeletal muscle insulin sensitivity. | 3 weeks | 
| Determine the effect of skipping breakfast on 24-hour plasma substrate, hormone concentrations and intramyocellular fatty acid mediators of lipotoxicity. | Multiple blood and skeletal muscle biopsy samples will be obtained during a 24-hour feeding study before and after the diet intervention to assess 24-hour plasma substrate, hormone concentrations and intramyocellular fatty acid mediators of lipotoxicity. | 3 weeks | 
| Determine the effect of skipping breakfast on the diurnal expression of clock genes and downstream metabolic targets involved in regulating adipose tissue lipolytic activity and skeletal muscle insulin action. | Serial biopsy samples (every 6 hours) of adipose tissue and muscle will be obtained during the 24-hour feeding study to evaluate diurnal expression patterns of i) clock genes [CLOCK, brain and muscle Arnt-like protein-1(BMAL1), period1 (PER1), period2 (PER2), and Dbp D site albumin promoter binding protein (DBP)] in adipose tissue and muscle and ii) putative downstream clock gene targets associated with lypolysis in adipose tissue [hormone-sensitive lipase(HSL) and adipocyte triglyceride lipase (ATGL)], skeletal muscle insulin action [glucose transporter type 4(GLUT4)] and skeletal muscle fatty acid metabolism [cluster of differentiation 36(CD36), uncoupling protein 3 (UCP3) and pyruvate dehydrogenase kinase, isozyme 4(PDK4)]. | 3 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Clock genes, Metabolism, Insulin sensitivity