This study is being done to evaluate how a ketone ester (KE) supplement affects heart function and health in people with diabetes compared to a placebo supplement (made with standard food ingredients that do not contain ketone esters).

This study is a single center, randomized controlled study of up to 30 subjects with diabetes. The study is designed to compare the acute effects of KE versus an energy and volume matched placebo on cardiac function and blood flow following a meal. Eligible subjects will have a known diagnosis of type 2 diabetes and will be selected from a larger population at the Ohio State University Wexner Medical Center. Enrolled subjects will be stratified by sex to ensure equal proportions of men and women in each group (KE and placebo) and then randomly assigned (1:1) to a group, before washing out and crossing over to the other group (KE or Placebo). The order of treatment will be randomized such that half the cohort starts first with KE, and the other half with Placebo.

CMR will be performed on the days of supplement ingestion. CPET may be performed prior to starting the first intervention. Following a 2-wk washout period, each patient will replicate the acute CMR visit with the opposing treatment (KE or Placebo).

CMR will be used to evaluate cardiac function, myocardial blood flow, and cardiac and vascular function. CMR will provide insightful data on the magnitude, timeline, and functional impact of nutritional ketosis on cardiovascular function and myocardial blood flow in patients diagnosed with T2D.

Inclusion Criteria:

1. Age ≥ 18 years old and ≤ 80 years old
2. Type II Diabetes Mellitus
3. Stable medical therapy for at least 1 months as determined by the treating physician (no plan to change between the two testing sessions)
4. Dose of oral diuretics changes allowed, but must be stable for 1 week prior to randomization
5. Body Mass Index (BMI) ≥ 25
6. Ability to participate in exercise treadmill testing (only if CPET is performed)
7. Ability to sign written consent

Exclusion Criteria:

1. Women who are pregnant, current breast-feeding, or have intention to become pregnant while in the trial
2. Known allergy or sensitivity to Gadolinium based contrast agents
3. Implanted pacemaker, cardioverter defibrillator, cardiac resynchronization therapy, left ventricular assist device
4. Other metallic implants/aneurysm clips that are contraindicated in MRI
5. Claustrophobia
6. History of severe kidney disease with eGFR<30 ml/kg/1.73m2
7. Type I diabetes
8. History of diabetic ketoacidosis
9. Prior diagnosis of oxygen dependent pulmonary disease
10. Body Mass Index (BMI) < 25
11. Major surgery (major according to the investigator's assessment) performed within 90 days prior to screening, or major scheduled elective surgery (e.g. hip replacement) within 90 days after screening
12. Acute or chronic liver disease, defined by serum levels of transaminases or alkaline phosphatase more than three times the upper limit of normal at screening
13. Gastrointestinal surgery or gastrointestinal disorder that might interfere with supplement consumption. Prior bariatric surgery allowed if weight-stable for past 3 months.
14. Any documented active or suspected malignancy or history of malignancy within 2 years prior to screening, except appropriately treated basal cell carcinoma of the skin, in situ carcinoma of the uterine cervix, or low-risk prostate cancer (subjects with pre-treatment prostate-specific antigen levels of <10 ng/mL, and biopsy Gleason scores of ≤6 and clinical stage T1c or T2a)
15. Presence of any disease other than diabetes that results in a life expectancy of <1 year (in the opinion of the investigator)
16. Current enrolment in another investigational device or drug study or completion within <30 days of a trial of another investigational device or drug study.
17. Chronic alcohol or drug abuse or any condition that, in the investigator's opinion, will make the subject unlikely to fulfil the trial requirements or complete the trial
18. Any other clinical condition that might jeopardize subject safety during participation in this trial or prevent the subject from adhering to the trial Protocol.
19. Unable or unwilling to follow guidelines of assigned supplement group.
20. Allergy to test article ingredients, or lactose intolerance
21. The subject cannot currently be on a low-carb diet plan. 30-day washout would be required.
22. Refusal to consent