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| ID | Type | Description | Link |
|---|---|---|---|
| 5U01DC013529 | U.S. NIH Grant/Contract | View source |
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| Name | Class |
|---|---|
| Monell Chemical Senses Center | OTHER |
| National Institute on Deafness and Other Communication Disorders (NIDCD) | NIH |
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Overconsumption of carbohydrates has been implicated as a cause of significant public health problems including obesity and diabetes. The most effective approach to alter dietary pattern and improve public health is unknown. Gradual and abrupt changes in dietary pattern have been tried in small, uncontrolled trials, but it is not clear which approach is most effective. The primary objective of this study is to evaluate different approaches to changing dietary pattern for altering flavor perception in foods and beverages and for altering preference for flavor.
This comprehensive, well-controlled diet study aims to evaluate and compare different approaches to alter dietary pattern, especially macronutrient profile. The investigators propose a prospective, randomized trial that is designed to overcome the above limitations to test the hypothesis that changing dietary macronutrient profile can change taste perception and food preference. Data from this study will provide information that policy makers, regulators, and the food industry can use to develop successful approaches (gradual or otherwise) for providing healthy diets in the marketplace.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Diet composition 1 | Experimental | A diet with a specified macronutrient composition different from arms 2 and 3. |
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| Diet composition 2 | Experimental | A diet with a specified macronutrient composition different from arms 1 and 3. |
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| Diet composition 3 | Experimental | A diet with a specified macronutrient composition different from arms 1 and 2, based on the current information about the US macronutrient composition. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Diet composition 1 | Other | A diet with a specified macronutrient composition different from arms 2 and 3. |
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| Measure | Description | Time Frame |
|---|---|---|
| Taste intensity of food | Rating taste intensity from barely detectable to strong using a general labeled magnitude scale. The name of the scale is the general labeled magnitude scale. The value of the response is recorded on the scale as "barely detectable", "weak", "moderate, strong", "very strong", and "strongest imaginable sensation of any kind." None of these responses is considered better or worse than any other. | Month 1 |
| Taste intensity of food | Rating taste intensity from barely detectable to strong using a general labeled magnitude scale. The name of the scale is the general labeled magnitude scale. The value of the response is recorded on the scale as "barely detectable", "weak", "moderate, strong", "very strong", and "strongest imaginable sensation of any kind." None of these responses is considered better or worse than any other. | Month 2 |
| Taste intensity of food | Rating taste intensity from barely detectable to strong using a general labeled magnitude scale. The name of the scale is the general labeled magnitude scale. The value of the response is recorded on the scale as "barely detectable", "weak", "moderate, strong", "very strong", and "strongest imaginable sensation of any kind." None of these responses is considered better or worse than any other. | Month 3 |
| Taste intensity of food | Rating taste intensity from barely detectable to strong using a general labeled magnitude scale. The name of the scale is the general labeled magnitude scale. The value of the response is recorded on the scale as "barely detectable", "weak", "moderate, strong", "very strong", and "strongest imaginable sensation of any kind." None of these responses is considered better or worse than any other. | Month 4 |
| Taste intensity of food |
| Measure | Description | Time Frame |
|---|---|---|
| Diet-related adverse events | Adverse events related to the diet tabulated by study-arm and severity. | Daily during the Baseline (Month 1), Months 2-6 |
| Diet-related early discontinuation from intervention |
| Measure | Description | Time Frame |
|---|---|---|
| Glucose | Glucose is a sugar that circulates in the blood and is used as an energy source for many cells. Glucose will be measured to determine how the treatment is affecting blood glucose regulation. Glucose is measured in units of mg/dL. | Baseline (Month 1) week 3 or 4, Months 2-4, Month 6 |
| Insulin |
Exclusion criteria Younger than 25 years old and older than 80 years old at the beginning of the intervention.
Have body weight less than 110 lbs.
Known (self-reported) allergy or adverse reaction to study foods or ingredients
Added sugars intake at baseline < 10% of total energy.
A dietary pattern inconsistent with the dietary intervention (i.e., vegan, vegetarian, extremes of protein, fat, carbohydrate intake).
Body mass index less than 18 or greater than 40 kg/m2
Women who have given birth during the previous 12 months, are pregnant, are lactating, or plan to become pregnant during the study.
Use of appetite suppressants or other anti-obesity medication during the past 6 months.
History of bariatric or certain other surgeries related to weight control.
History or presence of diabetes, kidney disease, liver disease, certain cancers, gout, hyperthyroidism, untreated or unstable hypothyroidism, gastrointestinal disease, pancreatic disease, other metabolic diseases, malabsorption syndromes, phenylketonuria, or endocrine disorders that may interfere with the study outcomes.
Individuals with any gastrointestinal issues, including bariatric surgery, inflammatory bowel disease, suspected or known strictures, fistulas or physiological/mechanical GI obstruction, nutrient malabsorption disease, or Crohn's Disease Smokers or other tobacco/marijuana users (within 6 months prior to the study).
History of eating disorders or other dietary patterns which are not consistent with the dietary intervention (e.g., vegetarians).
Known taste or smell disorders, including weak or absent sense of taste or smell (screening procedures include a basic taste and smell sensitivity tests), abnormal taste in the mouth (e.g., bitter or metallic "phantom" tastes), or other taste abnormality.
Use of medications within one month prior to the study that moderately to severely affect taste.
Tested positive for COVID-19 in the past 4 weeks.
Volunteers who have lost or gained >10% of body weight within the last 12 months or who plan to initiate a weight loss program during the next 12 months.
Self-report of alcohol or substance abuse within the past 12 months and/or current acute treatment or rehabilitation program for these problems (long-term participation in Alcoholics Anonymous is not an exclusion); evaluated using USAUDIT.
Other medical, psychiatric, or behavioral factors that in the judgment of the Principal Investigator may interfere with study participation or the ability to follow the intervention protocol.
Unable or unwilling to give informed consent or communicate with study staff.
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| Name | Affiliation | Role |
|---|---|---|
| Paul Wise, PhD | Monell Chemical Senses Center | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| USDA-ARS, Beltsville Human Nutrition Research Center | Beltsville | Maryland | 20705 | United States |
| Type | Date | Date Unknown |
|---|---|---|
| Release | Apr 7, 2026 | |
| Reset | Apr 27, 2026 | |
| Release | Jun 8, 2026 | |
| Reset | Jul 2, 2026 |
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| Release Date | Unrelease Date | Unrelease Date Unknown | Reset Date | MCP Release Number |
|---|---|---|---|---|
| Apr 7, 2026 | Apr 27, 2026 | |||
| Jun 8, 2026 |
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The intervention is of foods which will look identical. Volunteers will know the color of their treatment assignment but not the actual identity of their treatment. The investigators will use a double masking protocol in which investigators and outcome assessors (study staff who collect primary and secondary measures and data analysts) will not know the treatment assignments or treatment coding (color coded) scheme.
| Diet composition 2 | Other | A diet with a specified macronutrient composition different from arms 1 and 3. |
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| Diet composition 3 | Other | A diet with a specified macronutrient composition different from arms 1 and 2, based on the current information about the US macronutrient composition. |
|
Rating taste intensity from barely detectable to strong using a general labeled magnitude scale. The name of the scale is the general labeled magnitude scale. The value of the response is recorded on the scale as "barely detectable", "weak", "moderate, strong", "very strong", and "strongest imaginable sensation of any kind." None of these responses is considered better or worse than any other.
| Month 6 |
| Taste preference | Most liked concentration. Foods will be scaled as g flavor/100 g food. | Month 1 |
| Taste preference | Most liked concentration. Foods will be scaled as g flavor/100 g food. | Month 2 |
| Taste preference | Most liked concentration. Foods will be scaled as g flavor/100 g food. | Month 3 |
| Taste preference | Most liked concentration. Foods will be scaled as g flavor/100 g food. | Month 4 |
| Taste preference | Most liked concentration. Foods will be scaled as g flavor/100 g food. | Month 6 |
Subject withdraws citing issues with the study diet, or investigators withdraw the subject from the study due to concerns over how the subject reacts to the study diet.
| Daily during the Baseline (Month 1), Months 2-6 |
Insulin is a hormone that helps control blood glucose concentration. Insulin will be measured to determine how the treatment is affecting blood glucose regulation. Insulin is measured in units of microIU/mL. |
| Baseline (Month 1) week 3 or 4, Months 2-4, Month 6 |
| c-peptide | c-peptide is a peptide that is formed during the production of insulin. C-peptide will be measured to determine how the treatment is affecting insulin response and blood glucose regulation. c-peptide is measured in units of ng/mL. | Baseline (Month 1) week 3 or 4, Months 2-4, Month 6 |
| Glucagon | Glucagon is a hormone that helps control blood glucose concentration. Glucagon will be measured to determine how the treatment is affecting blood glucose regulation. Glucagon is measured in units of pg/mL. | Baseline (Month 1) week 3 or 4, Months 2-4, Month 6 |
| Glucagon-like peptide-1 (GLP-1) | GLP-1 is a hormone that helps control blood glucose concentration. GLP-1 will be measured to determine how the treatment is affecting blood glucose regulation. GLP-1 is measured in units of pg/mL. | Baseline (Month 1) week 3 or 4, Months 2-4, Month 6 |
| Anandamide | Anandamide is the precursor of a class of physiologically active substances which are involved in brain chemistry. Anandamide will be measured to determine how the treatment is affecting blood compounds that are associated with reward. Anandamide is measured in units of ng/mL. | Baseline (Month 1) week 3 or 4, Months 2-4, Month 6 |
| 2-arachidonyl glycerol (2-AG) | 2-AG is the precursor of a class of physiologically active substances which are involved in brain chemistry. 2-AG will be measured to determine how the treatment is affecting blood compounds that are associated with reward. 2-AG is measured in units of ng/mL. | Baseline (Month 1) week 3 or 4, Months 2-4, Month 6 |
| Sweet taste receptors genotype | Genotyping describes the genetic make-up. The known variants of sweet receptor subunit TAS1R3 will be genotyped. Genotype will be measured as a specific sequence of the nucleobases cytosine, guanine, adenine and thymine. | Baseline month (once) |
| Body weight | Body weight is the mass of a person. Body weight is measured wearing street clothes without shoes or other heavy items in the pockets. Body weight is used to adjust energy intake to maintain weight maintenance. Body weight is measured in kg. | Baseline, Months 2-4 M-F, Month 6 at end of study |
| Waist circumference | Waist circumference is the distance around an individual at a specific location. Waist circumference is measured in cm. | Screening and Month 6 at end of study |
| Blood pressure | Blood pressure is a measure of the pressure produced by the heart on the walls of the blood vessels at different times during the heartbeat. Blood pressure is measured in mm Hg (mercury). | Screening and Month 6 at end of study |
| Power of Food Scale | A questionnaire that measures factors related to food preference and eating behavior. There are 15 items on the questionnaire. Each item is recorded as a 5-point Likert scale with a value of 1, 2, 3, 4, or 5 corresponding to "I don't agree", "I agree a little", "I agree somewhat", "I agree quite a bit, and "I strongly agree". A total score is determined as the sum of the responses. None of these responses is considered better or worse than any other. | Baseline and Month 6 end of study |
| Emotional Eating Scale | A questionnaire that measures factors related to food preference and eating behavior. There are 25 items on the questionnaire. Each item is recorded as a 5-point Likert scale with a value of 1, 2, 3, 4, or 5 corresponding to "no desire to eat", "a small desire to eat", "a moderate desire to eat", "a strong urge to eat", or "an overwhelming urge to eat." A total score is determined as the sum of the responses. None of these responses is considered better or worse than any other. | Baseline and Month 6 end of study |
| Three Factor Eating Questionnaire | A questionnaire that measures factors related to food preference and eating behavior. | Baseline and Month 6 end of study |
| Dutch Eating Behaviour Questionnaire | A questionnaire that measures factors related to food preference and eating behavior. | Baseline and Month 6 end of study |
| Yale Food Addiction Scale | A questionnaire that measures factors related to food preference and eating behavior. There are 16 items on the questionnaire that are scored as a 5-point Likert scale with a value of 0, 1, 2, 3, or 4, corresponding to "never", "once a month", "2-4 times a month", "2-3 times a week", or "4 or more times or daily." There is 1 item on the questionnaire that is scored as a 5-point Likert scale with a value of 0, 1, 2, 3, or 4, corresponding to "1 or fewer times", "2 times", "3 times", "4 times", or "5 or more times." There are 8 items scored as "no" (0) or "yes" (1). A total score is determined as the sum of the responses. None of these responses is considered better or worse than any other. | Baseline and Month 6 end of study |
| Barrat Impulsiveness Scale | A questionnaire that measures factors related to food preference and eating behavior. There are 11 items on the questionnaire that are scored as a 4-point Likert scale with a value of 1, 2, 3, or 4 corresponding to "rarely/never", "occasionally", "often", or "almost always/always." A total score is determined as the sum of the responses. None of these responses is considered better or worse than any other. | Baseline and Month 6 end of study |
| Dietary Satisfaction Questionnaire | A questionnaire that measures factors related to food preference and eating behavior. | Baseline, weekly during Months 3-5, and Month 6 end of intervention |
| Food Craving Inventory | A questionnaire that measures factors related to food preference and eating behavior. | Baseline, weekly during Months 3-5, and Month 6 end of intervention |
| Jul 2, 2026 |