Type1diabetes, Low Carbohydrate DietNCT04955691
Metabolic Changes Induced by a Very Low Carbohydrate Diet in Youth With Type 1 Diabetes
A study testing low carbohydrate diet and standard carbohydrate diet in people with Type1diabetes, Low Carbohydrate Diet, run by Yale University at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 12 to 21 years
- Conditions the study is for
- Type1diabetes, Low Carbohydrate Diet
- What is being tested?
- low carbohydrate diet and standard carbohydrate diet
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 19 participants
- Where
- 1 siteUnited States
- Study dates
- 29 Jul 2021to 6 Aug 2024
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 12 to 21 years
- All sexes
- No healthy volunteers
- Child, Adult
Who may be able to join
- 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
Show all 10Show fewer
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
United States1 site
Yale-New Haven Hospital
New Haven, Connecticut, 06511
About this study
Official title: Metabolic and Neurological 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.
Read the detailed description
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.
- Conditions
- Type1diabetes, Low Carbohydrate Diet
- Being tested
- low carbohydrate diet, standard carbohydrate diet
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
low carbohydrate dietOther
Participants will engage in a diet that limits carbohydrate intake to 15% of total daily calories for 2 weeks.
standard carbohydrate dietOther
Participants will engage in a diet that recommends standard carbohydrate intake with respect to total daily calories for 2 weeks.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Other: standard carbohydrate diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 2 weeks
Secondary outcomes (2)
Percent Time Spent With Hypoglycemia.
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.
Measured: 2 weeks
Percent Time Spent With Hyperglycemia
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.
Measured: 2 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Jul 2021
- Study start29 Jul 2021
- Primary completion6 Aug 2024
- Study completion6 Aug 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Type1diabetes, Low Carbohydrate DietStudies of the same condition, open and under way.
- More trials run by Yale UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 19 participants (actual)
Sponsor and investigators
- Lead sponsor
- Yale University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Laura M Nally, M.D., Principal investigator, Yale University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04955691
- Sponsor's protocol ID
- 2000029479
- Other IDs
- 1K23DK128560-01, 2P30DK045735-26
- Status last verified
- Sep 2025
- First submitted
- 1 Jul 2021
- Last updated
- 16 Oct 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 16 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Metabolic and Neurological Changes Induced by a Very Low Carbohydrate Diet in Youth With Type 1 Diabetes
- ClinicalTrials.gov ID
- NCT04955691
- Acronym / sponsor ID
- 2000029479
- Conditions
- Type1diabetes, Low Carbohydrate Diet
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 19 participants (actual)
- Lead sponsor
- Yale UniversityUniversity, hospital or other
- Collaborators
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Study start
- 29 Jul 2021 (actual)
- Primary completion
- 6 Aug 2024 (actual)
- Study completion
- 6 Aug 2024 (actual)
- First posted
- 9 Jul 2021 (actual)
- Results
- Posted 16 Oct 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
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.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| low carbohydrate diet | Experimental | Other: low carbohydrate dietIn 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. |
| standard carbohydrate diet | Active comparator | Other: standard carbohydrate dietIn 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. |
Who may qualify
- Ages
- 12 to 21 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
Key inclusion criteria (10 listed)
- 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
Key exclusion criteria (8 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| low carbohydrate dietParticipants will engage in a diet that limits carbohydrate intake to 15% of total daily calories for 2 weeks. | Other | low carbohydrate diet |
| standard carbohydrate dietParticipants will engage in a diet that recommends standard carbohydrate intake with respect to total daily calories for 2 weeks. | Other | standard carbohydrate diet |
Primary outcome
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.
2 secondary outcomes
Percent Time Spent With Hypoglycemia.
Time frame: 2 weeks
Percent Time Spent With Hyperglycemia
Time frame: 2 weeks
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Oct 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Laura M Nally, M.D. principal investigator
Yale University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing low carbohydrate diet and standard carbohydrate diet in people with Type1diabetes, Low Carbohydrate Diet, run by Yale University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 10 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 16 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 16 Oct 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Percent Time in the Optimal Glucose Range (time frame: 2 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Oct 2025.