Metabolic Changes Induced by a Very Low Carbohydrate Diet in Youth With Type 1 Diabetes

Inclusion Criteria: * Diagnosis of type 1 diabetes for at least 1 year * Hemoglobin A1c level \< 10% within the past 2 months * Provision of signed and dated informed consent form by the adult (if person is at least 18 years old) or parent and assent form if the participant is \<18 years old. * Stated willingness to comply with all study procedures and availability for the duration of the study * All sexes are eligible * Diagnosis of type 1 diabetes for at least 1 year * Insulin pump use for at least 2 months. * Ability to perform daily blood ketone checks, wear a continuous glucose monitor, willing to wear an activity monitor, willing to adhere to the study diets and keep a diet journal. * For females of reproductive potential: use of highly effective contraception for at least 1 month prior to screening and agreement to use such a method during study participation and for an additional 4 weeks after the end of the dietary intervention. * For males of reproductive potential: use of condoms or other methods to ensure effective contraception with partner Exclusion Criteria: * Current use of glucose-lowering agents other than insulin * Unstable psychiatric disorders, including eating disorders * Weight loss medications within the last 6 months * Pregnancy or lactation, or planning pregnancy within the next 6 months * BMI \< 19 kg/m2 for individuals 18 years of age or older * BMI \< 5%ile for individuals under 18 years * Weight less than 49 kg or 108 pounds * Other medical co…