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

NCT04955691 | Completed Results DMC

• 3 other identifiers: 20000294791K23DK128560-012P30DK045735-26
• Study Type: interventional
• Target: 19
• Locations: 1 country
• Sites: 1

Brief Summary

As more adolescents with type 1 diabetes (T1D) opt to follow very low carbohydrate diets to improve glucose control, it is becoming increasingly important to study the metabolic and neurological changes that occur on these diets and how these effect patient safety. Understanding the impact of dietary changes on metabolic and neurological factors will help guide clinical advice about the overall safety and efficacy of these diets in the pediatric T1D population. This work will be the basis of future studies testing dietary interventions to improve glycemic control and ensure that these dietary interventions are safe for growing youth with T1D.

Conditions

Type1diabetes, Low Carbohydrate Diet

Outcome Measures

Primary Outcomes (1)

• Percent Time in the Optimal Glucose Range

  Time in the optimal glucose range will be operationally defined as the percent time spent in the target range of 70-180 mg/dL during the 2 weeks.

  2 weeks

Secondary Outcomes (2)

• Percent Time Spent With Hypoglycemia.

  2 weeks

• Percent Time Spent With Hyperglycemia

  2 weeks

Other Outcomes (1)

• Human Factors

  8 weeeks

Study Arms (2)

low carbohydrate diet

EXPERIMENTAL

In this crossover study, participants will be randomized to either a low or standard carbohydrate for 2 weeks. Participants in the low carbohydrate group will limit carbohydrate intake to 15% of total daily calories.

Other: low carbohydrate diet

standard carbohydrate diet

ACTIVE COMPARATOR

In this crossover study, participants will be randomized to either a low or standard carbohydrate for 2 weeks. Participants in the standard carbohydrate group will follow an ad libitum diet with standard carbohydrate intake.

Other: standard carbohydrate diet

Interventions

low carbohydrate diet OTHER

Participants will engage in a diet that limits carbohydrate intake to 15% of total daily calories for 2 weeks.

low carbohydrate diet

standard carbohydrate diet OTHER

Participants will engage in a diet that recommends standard carbohydrate intake with respect to total daily calories for 2 weeks.

standard carbohydrate diet

Eligibility Criteria

• Age: 12 Years - 21 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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 conditions that may interfere with glucose metabolism and insulin sensitivity

Sponsors & Collaborators

• Yale University: lead
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): collaborator

Study Sites (1)

Yale-New Haven Hospital

New Haven, Connecticut, 06511, United States

Location

MeSH Terms

Interventions

Diet, Carbohydrate-Restricted

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Results Point of Contact

• Title: Laura Nally
• Organization: Yale school of Medicine

laura.nally@yale.edu

203-785-5831

Study Officials

• Laura M Nally, M.D.

  Yale University

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: Yes

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: July 1, 2021
• First Posted: July 9, 2021
• Study Start: July 29, 2021
• Primary Completion: August 6, 2024
• Study Completion: August 6, 2024
• Last Updated: October 16, 2025
• Results First Posted: October 16, 2025

Record last verified: 2025-09

Locations

US (1)