Liking Adaptation to Beverages of Varying Sweetness Levels Following Prolonged Exposure

This is a double-blind, controlled, parallel, randomized sensory study. The study will consist of two cohorts; habitual regular full-calorie Carbonated Soft Drink (CSD) consumers and habitual low-calorie CSD consumers. Each cohort will be randomized to one of 3 interventions for six months (24 weeks):

* Intervention 1: Control (full sweetness) beverage
* Intervention 2: Step-wise sweetness reduction series of beverages
* Intervention 3: Moderate sweetness (reduced sweetness) beverage

The primary outcome is to assess the perception changes in sweetness (magnitude scale) and sweetness liking (Likert scale) of a test product and a control product over a period of six months. The study endeavors to explore whether consumers of sweetened carbonated beverages can adapt liking to lower sweetness beverages after prolonged exposure of daily consumption of beverages with step-wise reduction of sweetness, or maintenance at reduced (moderate) sweetness.

Additional analysis will be to assess dietary compensation for sweetness in the step-wise and moderate reduction arms compared to the control arms (the full calorie and low calorie control beverages). Dietary analysis of calories and intakes of total sugar, added sugar, and servings of low-/non-calorie sweeteners will be assessed using a 3-day diet record pre-intervention and monthly for 6 months.


Eligibility Criteria:
Inclusion Criteria:

1. Healthy adults 25-55 years of age
2. Habitually consume regular or diet CSD
3. Willing and able to consume at least one orange CSD beverage daily for a total of 6 months and abstain from other sweetened beverages
4. Willing and able to complete questionnaires regarding dietary intake and sensory perception
5. Has internet access via computer, phone or other device and is able to maintain internet access throughout the trial in order to complete daily online questionnaires.
6. Participant is judged to be in good health based on a verbal health query and the general health and lifestyle questionnaire.
7. Participant is willing to maintain his or her habitual diet, smoking habits and physical activity patterns, including habitual use of study approved medications and/or dietary supplements throughout the study period.
8. Participant understands the study procedures and signs forms providing informed consent to participate in the study.

Exclusion Criteria:

1. Regular smoker (more than 1 cigarette per week)
2. History or presence of type 1 or 2 diabetes mellitus
3. Extreme dietary habits, including but not limited to vegetarian diets and intentional consumption of a high fiber diet, gluten-free, low-carb, vegan, ketogenic, and intermittent fasting (defined as intentional fasting for longer than 16 hours or alternate day fasting)
4. Extreme changes to physical activity
5. Females who is pregnant, planning to be pregnant during the study period, lactating, or is of childbearing potential and is unwilling to commit to the use of a medically approved form of contraception throughout the study period.
6. Recent history (within 12 months of screening; Visit 1) of alcohol or substance abuse. Alcohol abuse is defined as \>14 drinks per week (1 drink = 12 oz beer, 5 oz wine, or 1½ oz distilled spirits).
7. Individual has a condition that would interfere with his or her ability to provide informed consent, comply with the study protocol, or which might confound the interpretation of the study results or put the participant at undue risk.
8. Dislike of citrus flavored CSDs
9. Participation in another clinical trial within past 30 days
10. People who have phenylketonuria (low calorie sweetened beverages contain aspartame)