Effects of a Plant-Based Diet on Insulin Requirements and Obesity Markers in Obese Adults With T2DM

Inclusion Criteria: * Adults (older than 18 years old) of both genders, of all races and ethnicities. * Pre-existing diagnosis of Type 2 Diabetes Mellitus, as documented in medical records on basal with or without mealtime bolus insulin with no change to total of basal insulin and nutritional baseline insulin dosing \> 10% in the 1 month prior to consent and no changes to non-insulin antihyperglycemic medications in the 3 months prior to consent * If on a GLP-1 analog, on a stable dose for at least 3 months prior to the study enrollment * If on an SGLT2 inhibitor, on a stable dose for at least 3 months prior to the study enrollment * BMI of 27 kg/m2 or greater * Most recent HbA1c (within 6 months prior to consent) between 6.5% and 9.5% * Fluent in the English language (education about each diet will be in English) * Willingness and ability to participate in study protocol. * Agreeable to give informed consent. Exclusion Criteria: * Diagnosis of T1DM or type 1.5 diabetes mellitus * History of liver cirrhosis * Impaired renal function (GFR \< 45 ml/min) within 6 months prior to consent * History of hyperkalemia (potassium \> 5.4 meq/L) within 6 months prior to consent * Use of an insulin pump or expected to start during the study period * Use of warfarin (Coumadin) * Use of daily aspirin 500 mg or more or expected to start during the study period * Use of daily Vitamin C of 1,000 mg or more, unless willing to stop taking 1 week prior to baseline visit and for duration of study * Use of antipsychotics or systemic steroids within 3 months prior to consent * Use of any of the following weight-lowering pharmacotherapy within 3 months prior to consent: phentermine, orlistat, lorcaserin, phentermine/topiramate, bupropion/naloxone * The use of insulin secretagogues including sulfonylureas and glinides within 3 months prior to consent as this may increase the risk of hypoglycemia and alter assessment of daily insulin requirements during the study * The use of illicit drugs, defined as active use or use within 3 months prior to consent. * Engage in high risk alcohol use (defined as more than 4 drinks on any day or more than 14 drinks per week in men and more than 3 drinks on any day or 7 drinks per week in women). * Individuals who are pregnant or breastfeeding or intend to become pregnant during the duration of the study * Individuals who are following a vegetarian or vegan diet at the time of consent * Food allergies or intolerances that will interfere with diet adherence * Lack of access to a full-size refrigerator (required for storage of 3-4 days of prepared study meals) * Active malabsorption disorder, including uncontrolled symptomatic inflammatory bowel disease, or bariatric surgery in the past 1 year