Monell USDA Taste Test Study

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.

Eligibility Criteria:
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.