Nutrient Timing Following Resistance Exercise
Nutrient Timing Following Resistance Exercise
The purpose of the proposed study is to examine the timing of post-exercise feeding on 15
 hours post-exercise glycemic control and metabolic flexibility and in overweight and obese
 young men with a family history of type 2 diabetes.

 Aim 1 - To determine the temporal effects of post-exercise feeding (i.e., immediate
 post-exercise vs. 3 hours post-exercise) on glycemic control, peripheral insulin sensitivity,
 and metabolic flexibility (as evaluated by sleep RQ) in this same group of participants. We
 hypothesize that a 3 hour delay in nutrient ingestion will promote significantly greater
 improvements in glucose tolerance, metabolic flexibility, and peripheral insulin sensitivity
 both immediately and several hours post-ingestion.
The proposed study is cross-sectional and utilizes a within-subject design to study young men
 under two different nutrient timing protocols, which are randomly-ordered and spaced at least
 2 weeks apart.

 1. Participants will be screened for eligibility via phone or email and scheduled for an
 initial visit, in order to consent to the study and undergo some basic baseline
 evaluations. We will rely on participant self-report to verify absence of chronic
 disease or drug use.

 2. After consenting to the study, fasting blood glucose, height, weight, and air
 displacement plethysmography (BodPod®) will be conducted in the Clinical Exercise
 Physiology Laboratory at The George Washington University, in Washington, DC. These
 measures may occur on the same day as consent or at another scheduled time.

 3. After screening, consenting, and baseline assessments, participants will undergo 2
 experimental conditions, which will be randomly-ordered and approximately 2 weeks apart.
 If possible, both of these experimental visits will be scheduled shortly after the
 consent form is signed.

 4. A registered dietitian will instruct participants to eat a standardized (35 kcal∙kg body
 weight-1∙day-1) diet comprising 60% carbohydrate, 20% protein, and 20% fat for 3 days
 prior to both experimental sessions. This instruction will be administered after the
 BodPod® assessment is completed.

 5. Participants will report to the USDA Laboratory chamber at 7:30 AM for the experimental
 sessions. Height, weight blood pressure and heart rate will be measured, then a fasting
 blood sample (5 cc) will be obtained for determination of basal glucose & insulin
 concentrations. A Hidalgo Ambulatory Monitoring Sensor Array Vest (Equivital I: Hidalgo
 Ltd., Cambridge UK) will be worn by all participants measured in the calorimeter for the
 entire 48 period. This device measures heart rate (HR), heat flux, core body
 temperature, posture and physical activity (PA) from a built-in accelerometer.

 6. Then, the sensor portion of the CGMS then will be placed subcutaneously and the CGMS
 calibrated with whole blood using the Accu-Check Advantage (Roche Diagnostics,
 Indianapolis, IL) glucometer. Participants will then enter the whole room calorimeter
 (metabolic chamber) and complete a hunger scale. Hunger will be evaluated 10-20 minutes
 before the start of each meal and 2 hours after the resistance exercise bout. On the
 first day, participants eat a standard breakfast provided by the USDA kitchen at
 approximately 7:45-8:00AM.

 7. Gutierrez or a research assistant will take obtain glucometer readings before and 60
 minutes after each meal to calibrate the the CGMS. These evaluations will occur 4-6
 times over the course of the day.

 8. Standardized meals (lunch at 11:00AM and dinner at 7:00PM) will be provided for subjects
 by the USDA. Blood samples (5 cc each) will be collected prior to and 120 minutes after
 breakfast and lunch; and prior to and 30-, 60-, 90-, and 120-min following the start of
 the evening meal for the determination of post-meal responses in glucose & insulin. A
 trained phlebotomist with at least 50 successful IV catheter placements will place an IV
 catheter into the participant's median antecubital vein before the evening meal to
 facilitate multiple draws after the meal.

 9. On the second day, subjects will awake in the calorimeter at approximately 7:00 AM and a
 fasting blood sample (5 cc) will be obtained for determination of basal concentrations
 of glucose & insulin.

 10. At about 7:30 AM, subjects will eat a standardized breakfast to be consumed by 8:00 AM.
 Two hours after a standardized lunch meal, served at 11:00AM, participants will perform
 one of the following resistance exercise nutrient-timing protocols: immediate
 post-exercise nutrition at approximately 2:00 PM 3 hour post exercise nutrition at
 approximately 5:00 PM). All participants will undergo both experimental conditions at
 different testing sessions.
Inclusion Criteria:

 -  BMI= 18-30

 -  Report at least one first degree relative with family history of type 2 diabetes -
 Healthy with no self-report of diagnosis of chronic disease

 Exclusion Criteria:

 -  Self-report prior diagnosis of cardiovascular disease, pulmonary disease, adult
 asthma, dyspnea on exertion, current bronchitis, pneumonia, or tuberculosis, vascular
 disease, any intercurrent infection, hematologic/oncologic, any metastatic malignancy,
 anemia (hematocrit <35), thrombocytopenia, neutropenia, hematologic malignancy,
 bleeding dyscrasias, neurologic disorder, endocrine disorder, chronic renal diseases

 -  Any illegal drug use

 -  Coumadin, heparin, beta blocker, growth hormone supplementation, or illegal drug use

 -  Skeletal-muscular injury in the last 6 months (including severe sprains, broken bones,
 and tendon or ligament injuries)

 -  Alcohol use in excess of 2 drinks per day

 -  Smokers