ObesityNCT01661426
Weight Loss Diet Study: Low Carb vs Low Fat
A study testing Low-Carbohydrate Diet and Low-Fat Diet in people with Obesity and Insulin Resistance, run by Stanford University at 1 site in United States.
Trial summary
The traditional weight loss diet recommended by health professionals has been a low-fat, high-carbohydrate, calorie restricted diet. This recommendation has been challenged by a number of alternative dietary strategies, particularly low-carbohydrate diets. Read more about this study
- Who is it for?
- Ages 18 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Obesity, Insulin Resistance
- What is being tested?
- Low-Carbohydrate Diet and Low-Fat Diet
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 61 participants
- Where
- 1 siteUnited States
- Study dates
- Apr 2012to Mar 2013
- Phase
- Interventional
- Are there results?
- None posted in the registry
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 18 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Age: > or = 18 years of age
- Women: Pre-menopausal (self-report) and <50 years of age
- Men: <50 years of age
- Race/Ethnicity: All
- BMI (body mass index): 28-40 kg/m2 (need to lose >10% body weight to achieve healthy BMI)
- Body weight stable for the last two months, and not actively on a weight loss plan
Show all 12Show fewer
- No plans to move from the area over the next 14 months
- Available and able to participate in the evaluations and intervention for the study period
- Willing to accept random assignment
- To enhance study generalizability, people on medications not noted below as specific exclusions can participate if they have been stable on such medications for at least three months
- Ability and willingness to give written informed consent
- No known active psychiatric illness
Who cannot join
- Pregnant, lactating, within 6 months post-partum, or planning to become pregnant in the next 12 months; no menstruation for the previous 12 months
- Diabetes (type 1 and 2) or history of gestational diabetes or on hypoglycemic medications for any other indication
- Prevalent diseases: Malabsorption, renal or liver disease, active neoplasms, recent myocardial infarction, hypertension (except for those stable on hypertensive medications) (<6 months) (patient self-report and, if available, review of labs from primary care provider)
- Smokers (because of effect on weight and lipids)
- History of serious arrhythmias, or cerebrovascular disease
- Uncontrolled hyper- or hypothyroidism (TSH not within normal limits)
- Medications: Lipid lowering, diabetes medications, and those known to affect weight/energy expenditure
- Excessive alcohol intake (self-reported, >3 drinks/day)
Trial locations and contacts
1 site in 1 country.
United States1 site
Stanford University School of Medicine
Stanford, California, 94305
About this study
Official title: Weight Loss Diet Study: Low Carbohydrate vs. Low Fat and Insulin Resistance Status
The traditional weight loss diet recommended by health professionals has been a low-fat, high-carbohydrate, calorie restricted diet. This recommendation has been challenged by a number of alternative dietary strategies, particularly low-carbohydrate diets. In several recent weight loss studies insulin resistant adults had more success with low- vs. high-carbohydrate diets, in contrast to insulin sensitive adults who had either more success or comparable success with the low-fat diets. The investigators enrolled 61 people with a wide range of insulin sensitivity/resistance. After determining their insulin resistance status, the investigators will split them in the middle and randomly assign them to one of four groups for six months: (1) Low-Carbohydrate/Insulin Resistant (LC/IR); (2) Low-Carbohydrate/Insulin Sensitive (LC/IS); (3) Low-Fat/Insulin Resistant (LF/IR); and (4) Low-Fat/Insulin Sensitive (LF/IS) (15 people/group). After 6 months the participants will switch diet for the following 6 months, i.e. those randomized to the Low-Carbohydrate diet will switch to the Low-Fat diet and vice-versa. The primary outcome of this study is to determine whether weight loss success can be increased if one follows the dietary approach appropriately matched to their insulin resistance status. Secondary outcomes include fasting insulin, glucose, lipids, and fatty acid composition.
--------------------------------------------------------------------------------
Read the detailed description
The investigators hope to learn whether matching the weight loss diet to one's insulin resistance status will increase weight loss the success. The relevance of these findings is highlighted by the fact that the national recommendations for weight loss are to follow a high-carbohydrate, low-fat diet. This would imply that about half the population has been given the wrong advice in regards to the most successful dietary pattern for weight loss.
Plasma fatty acid composition patterns have been shown to be associated with both insulin resistance and/or carbohydrate intake. As secondary analyses, the investigators will explore: (1) differences in plasma fatty acid composition between insulin sensitive and resistant participants at baseline; (2) the correlations between insulin markers and plasma fatty acid composition at baseline; (3) the interaction between insulin status and diet on 6-month changes in the plasma fatty acid composition; (4) plasma fatty acid composition changes in participants on low fat and low carbohydrate diets after 6 months; and (5) the correlations between changes in insulin markers, dietary components, and plasma fatty acid composition after 6 months.
- Conditions
- Obesity, Insulin Resistance
- Being tested
- Low-Carbohydrate Diet, Low-Fat Diet
- Keywords
- Adults, Weight loss, Diet, Insulin Resistance, Fatty acid composition
- Medical subject headings
- Obesity, Insulin Resistance, Weight Loss
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Low-Carbohydrate DietBehavioural
Counseling/instruction on how to follow a healthy low-carbohydrate diet for 6 months. One evening class/week for 8 weeks (8 total classes). Then one class every other week for 8 weeks (4 total classes). Then one class every four weeks for 8 weeks (2 total classes): 14 evening classes, total.
Low-Fat DietBehavioural
Counseling/instruction on how to follow a healthy low-fat diet for 6 months. One evening class/week for 8 weeks (8 total classes). Then one class every other week for 8 weeks (4 total classes). Then one class every four weeks for 8 weeks (2 total classes): 14 evening classes, total.
| Study group | Role | What they receive |
|---|---|---|
| Low-Carbohydrate Diet first, then Low-Fat Diet (IR) | Active comparator | Participants who were more insulin resistant based on the median AUC for insulin concentrations measured from OGTT prior to randomization. Receives: Behavioral: Low-Carbohydrate Diet; Behavioral: Low-Fat Diet |
| Low-Fat Diet first, then Low-Carbohydrate Diet (IS) | Active comparator | Participants who were more insulin sensitive based on the median AUC for insulin concentrations measured from OGTT prior to randomization. Receives: Behavioral: Low-Carbohydrate Diet; Behavioral: Low-Fat Diet |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in weight
Weight change was calculated as the 12 month value minus the baseline value
Measured: Baseline and 12 months
Secondary outcomes (12)
Change in Fasting Insulin
Fasting insulin change was calculated as the 12 month value minus the baseline value
Measured: Baseline and 12 months
Change in insulin AUC
Insulin area under the curve (AUC) change was calculated as the 12 month value minus the baseline value.
Measured: Baseline and 12 months
Change in Fasting Glucose
Fasting glucose change was calculated as the 12 month value minus the baseline value.
Measured: Baseline and 12 months
Change in LDL-Cholesterol
LDL-cholesterol change was calculated as the 12 month value minus the baseline value.
Measured: Baseline and 12 months
Change in HDL-Cholesterol
HDL-cholesterol change was calculated as the 12 month value minus the baseline value.
Measured: Baseline and 12 months
Change in Triglycerides
Triglycerides change was calculated as the 12 month value minus the baseline value.
Measured: Baseline and 12 months
Change in systolic and diastolic blood pressure
Blood pressure change was calculated as the 12 month value minus the baseline value.
Measured: Baseline and 12 months
Plasma fatty acid composition at baseline
Comparison of the plasma fatty acid composition between insulin sensitive and resistant participants at baseline.
Measured: Baseline
Correlations between insulin markers and plasma fatty acid composition at baseline.
Measured: Baseline
Interaction between insulin status and diet on 6-month changes in the plasma fatty acid composition.
Measured: 6 months
Comparison of plasma fatty acid composition changes in participants on low fat and low carbohydrate diets after 6 months.
Measured: Baseline and 6 months
Correlations between changes in insulin markers, dietary components, and plasma fatty acid composition after 6 months.
Measured: 6 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted9 Aug 2012 (estimated)
- Study startApr 2012
- Primary completionMar 2013
- Study completionMar 2013
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by Stanford 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
- Model description
- The study employed a 2 x 2 crossover design: LF vs. LC diets and more IR vs. more IS. Study participants were classified as more IR or more IS based on the median AUC for insulin concentrations measured from an oral glucose tolerance test (OGTT) prior to randomization. Participants above the median were considered more IR and those below the median were considered more IS. A random number generator was used to stratify the randomization to LF vs. LC by insulin resistance status and gender. Participants followed their assigned diet for 6 months and then switched to the opposite diet for another 6 months.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 61 participants (actual)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Collaborators
- Hass Avocado Board
- Responsible party
- Principal investigator, Christopher Gardner, Stanford University
- Investigators
- Christopher D Gardner, PhD, Principal investigator, Stanford University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01661426
- Sponsor's protocol ID
- SU-07262012-10669
- Status last verified
- Feb 2023
- First submitted
- 7 Aug 2012
- Last updated
- 22 Feb 2023
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Gardner CD, Offringa LC, Hartle JC, Kapphahn K, Cherin R. Weight loss on low-fat vs. low-carbohydrate diets by insulin resistance status among overweight adults and adults with obesity: A randomized pilot trial. Obesity (Silver Spring). 2016 Jan;24(1):79-86. doi: 10.1002/oby.21331. Epub 2015 Dec 6.
PubMed 26638192
Study at a glance
From the registry record, last updated by the sponsor on 22 Feb 2023. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Weight Loss Diet Study: Low Carbohydrate vs. Low Fat and Insulin Resistance Status
- ClinicalTrials.gov ID
- NCT01661426
- Acronym / sponsor ID
- SU-07262012-10669
- Conditions
- Obesity, Insulin Resistance
- Keywords
- Adults, Weight loss, Diet, Insulin Resistance, Fatty acid composition
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 61 participants (actual)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Collaborators
- Hass Avocado Board
- Study start
- Apr 2012
- Primary completion
- Mar 2013 (actual)
- Study completion
- Mar 2013 (actual)
- First posted
- 9 Aug 2012 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The traditional weight loss diet recommended by health professionals has been a low-fat, high-carbohydrate, calorie restricted diet. This recommendation has been challenged by a number of alternative dietary strategies, particularly low-carbohydrate diets. In several recent weight loss studies insulin resistant adults had more success with low- vs. high-carbohydrate diets, in contrast to insulin sensitive adults who had either more success or comparable success with the low-fat diets. The investigators enrolled 61 people with a wide range of insulin sensitivity/resistance. After determining their insulin resistance status, the investigators will split them in the middle and randomly assign them to one of four groups for six months: (1) Low-Carbohydrate/Insulin Resistant (LC/IR); (2) Low-Carbohydrate/Insulin Sensitive (LC/IS); (3) Low-Fat/Insulin Resistant (LF/IR); and (4) Low-Fat/Insulin Sensitive (LF/IS) (15 people/group). After 6 months the participants will switch diet for the following 6 months, i.e. those randomized to the Low-Carbohydrate diet will switch to the Low-Fat diet and vice-versa. The primary outcome of this study is to determine whether weight loss success can be increased if one follows the dietary approach appropriately matched to their insulin resistance status. Secondary outcomes include fasting insulin, glucose, lipids, and fatty acid composition.
--------------------------------------------------------------------------------
Detailed description
The investigators hope to learn whether matching the weight loss diet to one's insulin resistance status will increase weight loss the success. The relevance of these findings is highlighted by the fact that the national recommendations for weight loss are to follow a high-carbohydrate, low-fat diet. This would imply that about half the population has been given the wrong advice in regards to the most successful dietary pattern for weight loss.
Plasma fatty acid composition patterns have been shown to be associated with both insulin resistance and/or carbohydrate intake. As secondary analyses, the investigators will explore: (1) differences in plasma fatty acid composition between insulin sensitive and resistant participants at baseline; (2) the correlations between insulin markers and plasma fatty acid composition at baseline; (3) the interaction between insulin status and diet on 6-month changes in the plasma fatty acid composition; (4) plasma fatty acid composition changes in participants on low fat and low carbohydrate diets after 6 months; and (5) the correlations between changes in insulin markers, dietary components, and plasma fatty acid composition after 6 months.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- The study employed a 2 x 2 crossover design: LF vs. LC diets and more IR vs. more IS. Study participants were classified as more IR or more IS based on the median AUC for insulin concentrations measured from an oral glucose tolerance test (OGTT) prior to randomization. Participants above the median were considered more IR and those below the median were considered more IS. A random number generator was used to stratify the randomization to LF vs. LC by insulin resistance status and gender. Participants followed their assigned diet for 6 months and then switched to the opposite diet for another 6 months.
| Arm | Type | Receives |
|---|---|---|
| Low-Carbohydrate Diet first, then Low-Fat Diet (IR) | Active comparator | Behavioral: Low-Carbohydrate Diet, Behavioral: Low-Fat DietParticipants who were more insulin resistant based on the median AUC for insulin concentrations measured from OGTT prior to randomization. |
| Low-Fat Diet first, then Low-Carbohydrate Diet (IS) | Active comparator | Behavioral: Low-Carbohydrate Diet, Behavioral: Low-Fat DietParticipants who were more insulin sensitive based on the median AUC for insulin concentrations measured from OGTT prior to randomization. |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (12 listed)
- Age: > or = 18 years of age
- Women: Pre-menopausal (self-report) and <50 years of age
- Men: <50 years of age
- Race/Ethnicity: All
- BMI (body mass index): 28-40 kg/m2 (need to lose >10% body weight to achieve healthy BMI)
Key exclusion criteria (8 listed)
- Pregnant, lactating, within 6 months post-partum, or planning to become pregnant in the next 12 months; no menstruation for the previous 12 months
- Diabetes (type 1 and 2) or history of gestational diabetes or on hypoglycemic medications for any other indication
- Prevalent diseases: Malabsorption, renal or liver disease, active neoplasms, recent myocardial infarction, hypertension (except for those stable on hypertensive medications) (<6 months) (patient self-report and, if available, review of labs from primary care provider)
- Smokers (because of effect on weight and lipids)
- History of serious arrhythmias, or cerebrovascular disease
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 DietCounseling/instruction on how to follow a healthy low-carbohydrate diet for 6 months. One evening class/week for 8 weeks (8 total classes). Then one class every other week for 8 weeks (4 total classes). Then one class every four weeks for 8 weeks (2 total classes): 14 evening classes, total. | Behavioural | Low-Carbohydrate Diet first, then Low-Fat Diet (IR), Low-Fat Diet first, then Low-Carbohydrate Diet (IS) |
| Low-Fat DietCounseling/instruction on how to follow a healthy low-fat diet for 6 months. One evening class/week for 8 weeks (8 total classes). Then one class every other week for 8 weeks (4 total classes). Then one class every four weeks for 8 weeks (2 total classes): 14 evening classes, total. | Behavioural | Low-Carbohydrate Diet first, then Low-Fat Diet (IR), Low-Fat Diet first, then Low-Carbohydrate Diet (IS) |
Primary outcome
Change in weight
Time frame: Baseline and 12 months
Weight change was calculated as the 12 month value minus the baseline value
12 secondary outcomes
Change in Fasting Insulin
Time frame: Baseline and 12 months
Change in insulin AUC
Time frame: Baseline and 12 months
Change in Fasting Glucose
Time frame: Baseline and 12 months
Change in LDL-Cholesterol
Time frame: Baseline and 12 months
Change in HDL-Cholesterol
Time frame: Baseline and 12 months
Change in Triglycerides
Time frame: Baseline and 12 months
Change in systolic and diastolic blood pressure
Time frame: Baseline and 12 months
Plasma fatty acid composition at baseline
Time frame: Baseline
Correlations between insulin markers and plasma fatty acid composition at baseline.
Time frame: Baseline
Interaction between insulin status and diet on 6-month changes in the plasma fatty acid composition.
Time frame: 6 months
Comparison of plasma fatty acid composition changes in participants on low fat and low carbohydrate diets after 6 months.
Time frame: Baseline and 6 months
Correlations between changes in insulin markers, dietary components, and plasma fatty acid composition after 6 months.
Time frame: 6 months
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Feb 2023.
- Background: PubMed 26638192Gardner CD, Offringa LC, Hartle JC, Kapphahn K, Cherin R. Weight loss on low-fat vs. low-carbohydrate diets by insulin resistance status among overweight adults and adults with obesity: A randomized pilot trial. Obesity (Silver Spring). 2016 Jan;24(1):79-86. doi: 10.1002/oby.21331. Epub 2015 Dec 6.
- Study description and summary of resultsLink provided by the sponsor.
- Individual participant dataSharing planned: No
Related trials for Obesity
Not yet recruiting
Transcutaneous Auricular Vagus Nerve Stimulation Combined With Lifestyle Intervention for Visceral Fat Reduction in Adults With Overweight or Obesity
Overweight, Obesity
Not yet recruitingObservational study
Assessing the Impact of Perceptions of Unpredictability on Objective Measures of Food Consumption and Metabolism
Healthy Volunteer, Obestity
RecruitingPhase 1/2
HS235 Study in Overweight and Obese Participants With Combined Pre and Post-Capillary Pulmonary Hypertension Due to Heart Failure With Preserved Ejection Fraction
Pulmonary Hypertension, Heart Failure With Preserved Ejection Fraction
Not yet recruitingPhase 3
ELEVATE-LIVER: A Study to Test Whether Survodutide Helps Improve Heart Structure and Function in People With Overweight or Obesity and Fatty Liver Disease
Obesity, Metabolic Dysfunction-associated Steatotic Liver Disease
Not yet recruitingObservational study
A Natural History of Genetic and Environmental Predictors of Pubertal Timing Among Youth With Obesity
Obesity
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.
Christopher D Gardner, PhD principal investigator
Stanford 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 Low-Fat Diet in people with Obesity and Insulin Resistance, run by Stanford 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 12 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 22 Feb 2023. 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?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
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?
Change in weight (time frame: Baseline and 12 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT01661426, which also lists 1 linked publication.
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 22 Feb 2023.