Inclusion Criteria:
* Inclusion Criteria
* Boys or girls
* Ages 8-10 years
* All races
* All ethnicities
* Children who were determined to have normal weight (BMI \<85th percentile) already determined under Mitochondria (MI) Energy (IRB Protocol: 260376)
* Participants willing to stop taking nutritional supplements (e.g., multivitamins, vitamin D, fish oil, probiotics, prebiotics, immune boosters, and others) for at least 2 weeks prior to each study testing visit
* Children without an infection requiring antibiotics willing to be rescheduled after at least 2 months of finalizing antibiotic treatment.
* Children without viral infections such as diarrhea, cold, or flu willing to be rescheduled after at least 2 weeks of resolution of symptoms.
* Children determined sedentary or active, based on both peak oxygen uptake (VO2) and accelerometer data, as described below: Children who completed a peak fitness test during MI Energy (IRB Protocol: 260376), and for whom peak VO2 data are as follows:
Peak ⩒O2, ml·min-1·fat free mass index (FFMI)-1 Boys Girls Boys Girls
* 89 ≤ 80 ≥115 ≥105 FFMI, fat-free mass index
AND
Children who completed accelerometer measures during MI Energy (IRB Protocol: 260376), and for whom average daily activity counts and/or minutes of moderate to vigorous physical activity are as follow:
Sedentary Active Activity counts/day \<2,924,494 ≥3,767,075 Minutes of Moderate to vigorous physical activity/day \<60 ≥60
Children who completed National Survey of Children's Health and Youth Risk Behavior Survey (NSCH-YRBS) questionnaire during MI Energy study (IRB Protocol: 260376). Children who report ≥3 hours/day of Television (TV) (Sedentary) or ≤2 hours/day of TV (Active) will be considered
* Children who completed Dual-energy x-ray absorptiometry (DXA) measures during MI Energy study (IRB Protocol: 260376)
* Children whose parents consented to the following in the MI Energy study (IRB Protocol: 260376): o A) be contacted about future follow-up studies to MI Energy, and having the data that is collected about their child in MI Energy being used also in these follow-up studies; and
* B) information collected in the MI Energy study may be used in future research related to bioenergetics (for example, blood cell mitochondria function), nutrition, obesity, cardiovascular health, or development; and
* C) any biological samples collected in the MI Energy study may be used in future research related to bioenergetics (for example, blood cell mitochondria function), nutrition, obesity, cardiovascular health, or development.
Exclusion Criteria:
* • Participants who have been excluded from participation in the study MI Energy (IRB Protocol: 260376)
* Participants whose parents report any change in medical history that may potentially affect participation and/or study outcomes as determined by PI
* Weight loss \>3 kg in last 6 months
* Taking medications that knowingly influences protein metabolism
* Phenylketonuria
