The goal of this clinical trial is to test whether replacing sugary sodas with unsweetened, flavored sparkling waters can reduce added sugar intake and improve health in Black/African American and Latine adolescents with obesity who prefer sweet-tasting beverages. The main questions it aims to answer are:

• Does replacing sugary sodas with water change liking for sugary drinks, and water?
• Do shifts in liking for sweetness lead to improved diet quality and cardiometabolic health?

Researchers will compare replacing sugary sodas with one of three alternative beverages: unsweetened sparkling water, plain water, and beverages with gradually reduced sugar to determine which strategy is most effective.

Participants will:

• Replace sugary sodas with study drinks for 4 weeks
• Complete taste tests to measure their liking for and sensory experience of sweetness over 8-weeks
• Provide dietary recalls, body measurements, and blood samples over 8-weeks

This randomized controlled trial aims to evaluate the effects of replacing sugar-sweetened sodas with unsweetened, flavored sparkling waters, progressively sugar-reduced sodas, or plain water in adolescents who are classified as "sweet-likers"-individuals who prefer higher concentrations of sugar in beverages. The study focuses on a high-risk group: adolescents ages 12-18 who self-identify as Black/African American or Latine and have obesity (BMI >95th percentile).

63 adolescents who are classified as sweet-likers and meet additional inclusion criteria will be enrolled in a randomized 3-arm intervention for 4 weeks, with an additional 4-week follow-up period. Participants will be randomized into one of the following groups:

USW (Unsweetened Sparkling Water): Replaces sodas with flavored, unsweetened carbonated water.

PRS (Progressively Reduced Sugar): Replaces sodas with carbonated beverages with decreasing sugar concentrations, ending with unsweetened carbonated water.

PW (Plain Water - Control): Replaces sodas with still, plain water.

Participants will replace all typical sugary sodas with study beverages during the 4-week intervention. Study assessments include sensory testing for liking, sweetness intensity, and "just about right" level of sweetness in sparkling and plain water at baseline, week 2, week 4, and week 8. Additionally, dietary intake (via 24-hour dietary recalls), anthropometrics (height, weight, waist circumference), blood pressure, and blood biomarkers (fasting glucose, insulin, triglycerides) will be measured at baseline, week 4, and week 8.

The primary hypothesis is that exposure to unsweetened beverages (especially in the USW and PRS groups) will reduce participants' liking for higher concentrations of sugar in beverages and increasing liking for lower concentrations of sugar in beverages. It is also hypothesized that these changes may correspond with improvements in cardiometabolic markers, particularly serum triglycerides. Insulin resistance (HOMA-IR), blood pressure, and body weight will also be measured but are less likely to shift in the relatively short time period (8 weeks).

This trial addresses the persistent challenge of high SSB consumption in racial and ethnic minority adolescents-a group that faces disproportionate risk of obesity, prediabetes, and cardiometabolic disease. By integrating sensory science with behavior change, this intervention seeks to develop more effective strategies to support reduced sugar intake in adolescents who have strong preferences for sweetness.

Inclusion Criteria:

• Adolescents ages 12 to 18 who display a "sweet-liker" pattern, characterized by a preference for higher concentrations of sugar in beverages, specifically identifying 0.3M (10.3% sucrose) or above as their most liked sample.
• Have obesity (body mass index [BMI] > 95%). During screening, subjects' height and weight will be measured to calculate BMI, and BMI will be balanced across study arms using stratified randomization.
• Adolescents must also indicate a willingness to drink study beverages; not currently dieting/changing diet.

Exclusion Criteria:

• For the primary objective. Exclusion Criteria:

  • Adolescent participant is pregnant, since pregnancy affects taste perception
  • Participant is allergic or intolerant to the items we are testing.

For the secondary objective. Exclusion Criteria:

• Adolescent with type 1 or type 2 diabetes (self-declared or detected at screening visit through fasting glucose)
• Currently consume unsweetened, sparkling water two or more times per week.
• Adolescent participant is pregnant, since pregnancy affects taste perception
• Participant is allergic or intolerant to the items we are testing.
• Allergic or intolerant to the items that we are testing.

Individual participant data will not be shared due to the sensitive nature of the data collected from a minor population (adolescents), limited consent for data sharing. Future data sharing may be reconsidered following additional ethical review and participant re-consent where appropriate.

Not applicable. This is an open-label study; no parties are masked.