Eligibility Criteria:
Pediatric Inclusion Criteria:
* Children 10-17 years.
* Both genders (male and female)
* All children must have a Primary Care Physician and/or an Endocrinologist who must be aware that the child under their care will be part of the study.
* All children must have a Primary Care Physician and/or an Endocrinologist who is considering initiating metformin therapy now or in the near future as part of standard clinical care.
* Naïve to metformin.
* Either: Prediabetic children Or diabetic children under good glycemic control
Pediatric Exclusion Criteria:
* Children ages 10-17 who do not have parental consent and/or do not give assent
* Children living in foster care
* Children with allergies to foods in the breakfast menu
* Children who currently consume any alcohol
* Children on current antidiabetic medication or those who have been on any antidiabetic medication in the 3 months prior to enrolment
* Children with a history of /or concurrent chronic disease (eg. heart, kidney, liver disease or any type of malignancy or pre-malignant condition) that required hospitalization within the last 6 months
* Pregnancy
* Refusal by a female participant who is of child bearing potential and sexually active to use contraceptive methods such as oral contraceptive pills, barrier methods and abstinence
* Children weighing less than 36 kg
* Children with any condition that increases the risk of lactic acidosis (e.g. cancer, infection, congestive heart failure, renal disease )
* Children with history of recent hospitalization for surgery, dehydration, sepsis, hypoxemia (within the past 6 months)
* Children with history of weight loss, polyuria and polydipsia
* Children who are currently enrolled in a weight management program
* Children with known hypersensitivity to metformin
* Children with a fasting blood glucose of \>180mg/dl
* Children with a HbA1c level of ≥7%
* Children with glycosuria
* Children with clinical or laboratory evidence of hepatic disease- transaminase levels three times the upper normal range (Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT)) and/or a increased level of Gamma-glutamyltransferase (GGT), Prothrombin Time (PT), International Normalized Ratio (INR) from the reference normal range and a serum albumin less than the reference normal range of the Johns Hopkins Clinical Laboratories.
* If iodinated contrast is used on a participant, due to possible acute alteration of renal function resulting in increased risk of lactic acidosis, the participant will be excluded.
* Children with renal impairment
* In children \>50kg, renal impairment is defined by a serum creatinine 1.4 mg/dl or higher in females or 1.5mg/dl or higher in males OR estimated Glomerular Filtration Rates (eGFR) ≤60mL/min by the Schwartz formula.
* In children \<50kg, renal impairment is defined by eGFR \<100 mL/min by the Schwartz formula.
* Children with acid-base disturbance as defined by serum bicarbonate levels less than 20mEq/L or greater than 29mEq/L.
Adult Inclusion Criteria:
* Adults 18-79 years
* Both genders (male and female)
* All participants must have a Primary Care Physician and/or an Endocrinologist who must be aware that the adult under their care will be part of the study
* All participants must have a Primary Care Physician and/or an Endocrinologist who is considering initiating metformin therapy now or in the near future as part of standard clinical care.
* Naive to metformin
* EITHER: Prediabetic adults OR diabetic adults, under fair glycemic control:
Adult Exclusion Criteria:
* Pregnancy
* Adults who are not able to understand the Informed Consent document and who are unwilling to do the study
* Adults with allergies to any of the foods in the breakfast menu
* Adults on current antidiabetic medication or on any antidiabetic medication in the 3 months prior to enrolment.
* Adults with a history of /or concurrent chronic disease (e.g. heart, kidney, liver disease or any type of malignancy or pre-malignant condition) that required hospitalization within the last 6 months
* Refusal by a female participant who is of child bearing potential and sexually active to use contraceptive methods such as oral contraceptive pills, barrier methods and abstinence
* Adults with excessive current intake of alcohol (\>2 drinks/day for males and \>1 drink/day for females)
* Adults who have engaged in binge drinking (\>5 drinks within a 2 hour period) in the last 3 months
* Adults with history of recent hospitalization for surgery, dehydration, sepsis, hypoxemia (past 6 months)
* Hypersensitivity to metformin.
* Adults with fasting blood glucose of \>180mg/dl.
* Adults with HbA1c level of ≥8%
* Adults with glycosuria.
* Adults with any condition that increases the risk of lactic acidosis (e.g. cancer, infection, congestive heart failure, renal disease )
* Adults with clinical or laboratory evidence of hepatic disease- transaminase levels three times the upper normal range (AST and ALT) and/or a increased level of GGT, PT, INR from the reference normal range and a serum albumin less than the reference normal range of the Johns Hopkins Clinical Laboratories.
* If iodinated contrast is used on a participant, due to possible acute alteration of renal function resulting in increased risk of lactic acidosis, the adult participant will be excluded.
* Adults with renal impairment as defined by a serum creatinine 1.4 mg/dl or higher in females or 1.5mg/dl or higher in males OR estimated Glomerular Filtration Rates (eGFR) ≤60mL/min by Modification of Diet in Renal Disease (MDRD) formula.
* Adults with acid-base disturbance as defined as serum bicarbonate levels less than 20mEq/L or greater than 29mEq/L.
Adult Obese Control Inclusion Criteria:
* Age 18-79
* Both genders (male and female)
* BMI \> 30 kg/m2
Adult Obese Control Exclusion Criteria:
* Subjects previously or currently on any diabetes medication, including metformin, will be excluded.
* Pregnancy
* Subjects with history of or concurrent chronic disease (e.g. heart, kidney, liver disease or any type of malignancy or pre-malignant condition) that required hospitalization within the last 6 months will be excluded.
* Adults with allergies to any of the foods in the breakfast menu
* Adults with excessive current intake of alcohol (\>2 drinks/day for males and \>1 drink/day for females)
* Adults who have engaged in binge drinking (\>5 drinks within a 2 hour period) in the last 3 months