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Completed

NCT Number: NCT04955691

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

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.

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Key information

Conditions

Type1diabetes, Low Carbohydrate Diet

Age range

12 year–21 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Yale-New Haven Hospital

New Haven, Connecticut, 06511, United States

About this study

The primary objective of this randomized crossover study is to determine whether a very low carbohydrate diet improves glycemic changes (measured by continuous glucose monitors) when compared to a standard carbohydrate diet in youth with type 1 diabetes.

The secondary objectives of the study are to compare metabolic changes after 2 weeks on each diet using the 2-step hyperinsulinemic euglycemic-hypoglycemic clamp and stable isotope infusions. The euglycemic portion of the clamp will allow us to determine the hepatic glucose production and adipose tissue lipolysis. Secondary objectives also include measuring the neurohormonal response to hypoglycemia after 2 weeks on each diet.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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 conditions that may interfere with glucose metabolism and insulin sensitivity

Treatment and study plan

Low carbohydrate diet

Other

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

standard carbohydrate diet

Other

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

Primary outcomes

  1. Percent Time in the Optimal Glucose Range

    Time frame: 2 weeks

    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.

Secondary outcomes

  1. Percent Time Spent With Hypoglycemia.

    Time frame: 2 weeks

    Time spent with hypoglycemia will be operationally defined as the percent time spent in the hypoglycemic ranges during 2 weeks of diet. Level 2 hypoglycemia defined as <54 mg/dL. Level 1 hypoglycemia defined as 54-69 mg/dL.

  2. Percent Time Spent With Hyperglycemia

    Time frame: 2 weeks

    Time spent with hyperglycemia will be operationally defined as the percent time spent in the hyperglycemic ranges during 2 weeks of diet. Level 1 hyperglycemia defined as 181-250 mg/dL. Level 2 hyperglycemia defined as >250 mg/dL.

Other outcomes

  1. Human Factors

    Time frame: 8 weeeks

    To describe how participants feel about and react to following a very low carbohydrate diet, interviews will be conducted. Data will be coded and emerging patterns will be combined into descriptive themes.

Sponsors and collaborators

Lead sponsor

Yale University

Other

Collaborators

  • National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Registry information

Official study title

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

Important dates

Study start
2021
Primary completion
2024
Study completion
2024
First posted
Jul 9, 2021
Registry last updated
Oct 16, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.