This study is designed to examine the value of infusing BHB in type 1 diabetic subjects during experimentally induced hypoglycemic episode in conjunction with testing of cognitive function. This will lay the basis for subsequent trials exploring the novel use of therapeutic doses of oral ketone formulations that are currently under commercial development, which could serve as adjunct therapies to protect the brain from hypoglycemia in type 1 diabetic subjects experiencing recurrent hypoglycemia.

Healthy controls as well as type 1 diabetic subjects will undergo a hyperinsulinemic-hypoglycemic clamp with concomitant BHB or saline (control) infusion in random order. During each experimental condition the participants will complete a battery of validated cognitive tests that are sensitive to the cognitive impairment typically caused by hypoglycemia. An additional healthy control arm was added to the study design after the initial registration as a 2 arm study, to provide imaging results of normal healthy responses to hypoglycemia.

Inclusion Criteria:

1. Type 1 diabetes mellitus of > 5 years (C-peptide negative, age 18-60 years, on intensive insulin therapy (HbA1c <7.5%)
2. Non-diabetic volunteers, age 18-65 years that do not meet any of the exclusion criteria.

Exclusion Criteria:

1. Pregnancy
2. Significant baseline anemia (hemoglobin <11.0 or hematocrit < 33%)
3. A history of liver cirrhosis or porto-caval shunt surgery.
4. Any contraindications for MRI scanning.
5. Subjects that follow a vegetarian diet
6. Subjects that exercise heavily on a regular basis (i.e. marathon runners, body builders or other forms of excessive exercise as determined by the PI)
7. Subjects with a history of anxiety/ panic attacks