Group 1 (lean controls)  Inclusion Criteria:  BMI = 18.6-25 kg/m2 Male or female  Exclusion Criteria:  Diabetes (ADA criteria) Significant alcohol/drug abuse as per investigators judgement Amino acid-related diseases such as phenylketonuria Kidney disease Cardiac problems Cancer within the past 1 year Severe claustrophobia Pacemaker or other non-MR-compatible devices Pregnancy or breastfeeding.  Group 2 (overweight and obese individuals)  Inclusion Criteria:  BMI = 25-40 kg/m2 Male or female  Exclusion Criteria:  Diabetes (ADA criteria) Significant alcohol/drug abuse as per investigators judgement Amino acid-related diseases such as phenylketonuria Kidney disease Cardiac problems Cancer within the past 1 year Severe claustrophobia Pacemaker or other non-MR-compatible devices Pregnancy or breastfeeding Abdominal diameter >70 cm Fib4 score > 3.25.  Group 3 (individuals with type 1 diabetes)  Inclusion Criteria:  BMI = 18.6-40 kg/m2 Male or female C-peptide negative Insulin pump user  Exclusion Criteria:  Type 2 diabetes Closed loop user Significant alcohol/drug abuse as per investigators judgement Amino acid-related diseases such as phenylketonuria Kidney disease Cardiac problems Cancer within the past 1 year Severe claustrophobia Pacemaker or other non-MR-compatible devices Pregnancy or breastfeeding Abdominal diameter >70 cm Fib4 score > 3.25.