Effects of a Six-Day Whole-Diet Intervention on Taste Perception and Dietary Behaviour in Young Adults

Effects of a Six-Day Whole-Diet Intervention on Taste Perception, Dietary Behaviour, and Individual Differences in Young Adults

This study aims to investigate the effects of a specific diet modification on the pleasantness, desire, and saltiness intensities of selected foods and an ad libitum breakfast buffet through a randomized controlled trial with three arms. Participants will be randomized to either increase, decrease, or make no change to their daily intake of foods with a specific taste for six consecutive days, and outcomes will be assessed at two time points, at baseline (Day 1) and after the intervention (Day 7), alongside measures of adherence to the assigned diet. Each participant will receive an instruction to modify specific aspects of their diets for six days. This study is crucial for addressing diet-related health issues such as obesity, diabetes, and hypertension in Malaysia. By providing robust evidence on the effectiveness of specific diet modifications, the study can inform public health policies, improve dietary recommendations tailored to Malaysian cultural preferences, and promote long-term benefits.

Study Overview

• Status: Active, not recruiting
• Conditions: Hypertension; Sodium Excess; Salty Taste
• Intervention / Treatment: Other: Experimental: Increased Salty Food Intake; Other: Experimental: Decrease Salty Food Intake; Other: Active Comparator: Maintain Usual Diet

Detailed Description

Excess dietary sodium intake is a major modifiable risk factor for hypertension and cardiovascular disease. Public health strategies often assume that reducing exposure to salty foods will lower salt preference and encourage healthier food choices through sensory adaptation; however, evidence from whole-diet interventions conducted under real-world conditions remains limited and inconsistent. Dietary sodium consumption substantially exceeds recommended levels in many countries, including Malaysia, and contributes to the global burden of hypertension and cardiovascular disease. Public health sodium reduction programmes are based on the premise that lowering exposure to salty foods can gradually shift taste preferences towards less salty diets through sensory adaptation. However, evidence supporting this mechanism is mixed, and most previous studies have relied on controlled laboratory settings, single foods, or salt solutions rather than whole-diet interventions.

The study aims to determine whether short-term changes in dietary sodium exposure are sufficient to modify salt taste perception and related eating behaviors and to identify factors associated with individual variation in these responses. The primary objective is to determine whether increasing or decreasing exposure to salty foods over six days alters salt-related taste perception compared with maintaining usual dietary habits. Secondary objectives are to examine changes in sodium intake and appetite-related outcomes and to explore demographic and anthropometric factors associated with taste perception responses. The findings will improve understanding of short-term sensory adaptation to dietary sodium exposure and provide evidence relevant to sodium reduction policies, food reformulation efforts, and behavioral interventions aimed at reducing population sodium intake.

• Study Type: Interventional
• Enrollment (Actual): 115
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Malaysia
  • Selangor
    • Subang Jaya, Selangor, Malaysia, 47500
      • Department of Biomedical Sciences, Sir Jeffrey Cheah Sunway Medical School, Faculty of Medical and Life Sciences, Sunway University,.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Being a student or staff member of Sunway University or Sunway College
• Aged 18-35 years
• Able to communicate in English
• Regularly consuming breakfast
• Being willing and able to comply with all study procedures.

Exclusion Criteria:

• Vegan/smokers/with chronic medical conditions (e.g., hypertension or diabetes)
• Food allergies
• Pregnant or breastfeeding
• Currently dieting or attempting to lose weight
• History of smell or taste impairment
• Use medications or supplements that could affect taste perception.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Increase salty food consumption; Participants increase intake of salty foods and beverages.	Other: Experimental: Increased Salty Food Intake; Participants assigned to the increase group were instructed to increase their consumption of salty-tasting foods and beverages for six consecutive days (Days 1-6) while living in their usual environment. Participants selected their own foods and beverages but were encouraged to choose options consistent with a higher-salt dietary pattern. Written guidance and meal examples were provided to support implementation. Outcomes were assessed at baseline (Day 1) and after the intervention (Day 7).
Experimental: Decrease salty food consumption; Participants decrease intake of salty foods and beverages.	Other: Experimental: Decrease Salty Food Intake; Participants assigned to the decrease group were instructed to reduce their consumption of salty-tasting foods and beverages for six consecutive days (Days 1-6). Participants selected their own foods and beverages while attempting to minimize intake of high-salt items according to written guidance and examples. Outcomes were assessed at baseline (Day 1) and after the intervention (Day 7). A six-day, self-directed dietary intervention designed to reduce exposure to salty foods and beverages under free-living conditions. Participants modified their habitual diet without direct provision of foods by the investigators
Active Comparator: Maintain usual diet; Participants continue their habitual dietary practices	Other: Active Comparator: Maintain Usual Diet; Participants assigned to the maintain group were instructed to continue their usual eating habits and dietary practices for six consecutive days without making deliberate changes to salty food consumption. Outcomes were assessed at baseline (Day 1) and after the intervention (Day 7). A six-day control condition in which participants maintained their habitual dietary intake under free-living conditions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pleasantness	Pleasantness ratings, indicated after tasting three salty foods (Foods 1-3) and three non-salty foods (Foods 4-6), will be measured on a 10-point Likert scale. The rating scores will be averaged across the six test foods to generate composite scores. The aggregated pleasantness score will be used to capture overall taste responses rather than food-specific effects, consistent with whole-diet taste exposure theory.	Pleasantness ratings will be collected at baseline (Day 1) and Day 7
Desire to eat	Desire to eat ratings, indicated after tasting three salty foods (Foods 1-3) and three non-salty foods (Foods 4-6), will be measured on a 10-point Likert scale. The rating scores will be averaged across the six test foods to generate composite scores. The aggregated pleasantness score will be used to capture overall taste responses rather than food-specific effects, consistent with whole-diet taste exposure theory.	Desire to eat ratings will be collected at baseline (Day 1) and Day 7
Saltiness intensity	Saltiness intensity ratings, indicated after tasting three salty foods (Foods 1-3) and three non-salty foods (Foods 4-6), will be measured on a 10-point Likert scale. The rating scores will be averaged across the six test foods to generate composite scores. The aggregated pleasantness score will be used to capture overall taste responses rather than food-specific effects, consistent with whole-diet taste exposure theory.	Saltiness intensity ratings will be collected at baseline (Day 1) and Day 7

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dietary sodium intake	Dietary sodium intake will be estimated from pre- and post-foods consumed by each participant.	Dietary sodium intake is estimated at baseline (Day 1) and Day 7
Sodium Density	Sodium density (mg/g) will be computed to distinguish compositional from volumetric changes in sodium intake.	Sodium density will be assessed at baseline (Day 1) and Day 7
Appetite	Appetite will be rated on 0-10 Likert scales at the start of each test session.	Appetite will be assessed at the baseline (Day 1) and Day 7
Adherence	Adherence is a self-reported measure rated on a 10-point Likert scale.	Adherence was assessed only on Day 7

Collaborators and Investigators

• Sponsor: Sunway University
• Investigators: Principal Investigator: Yee-How Say, PhD, Department of Biomedical Sciences, Sir Jeffrey Cheah Sunway Medical School, Faculty of Medical and Life Sciences, Sunway University, 5, Jalan Universiti, Bandar Sunway, 47500 Subang Jaya, Selangor, Malaysia.

Publications and helpful links

General Publications

• Mojadadi A, Au A, Ortiz Cerda T, Shao JY, O'Neil T, Bell-Anderson K, Andersen JW, Webb J, Salah W, Ahmad G, Harris HH, Witting PK. Dietary supplementation of male mice with inorganic, organic or nanoparticle selenium preparations: evidence supporting a putative gut-thyroid-male fertility axis. Redox Rep. 2025 Dec;30(1):2495367. doi: 10.1080/13510002.2025.2495367. Epub 2025 Apr 25.
• Bielat AD, Rogers PJ, Appleton KM. Effects of a six-day, whole-diet sweet taste intervention on pleasantness, desire for and intakes of sweet foods: a randomised controlled trial. Br J Nutr. 2025 Jan 28;133(2):277-288. doi: 10.1017/S0007114524003209. Epub 2024 Dec 19.

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2026
• Primary Completion (Estimated): August 31, 2026
• Study Completion (Estimated): August 31, 2026

Study Registration Dates

• First Submitted: July 15, 2026
• First Submitted That Met QC Criteria: July 22, 2026
• First Posted (Actual): July 24, 2026

Study Record Updates

• Last Update Posted (Actual): July 24, 2026
• Last Update Submitted That Met QC Criteria: July 22, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: Sodium intake; Dietary sodium; Public health nutrition; Taste perception; Taste adaptation
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Metabolic Diseases; Water-Electrolyte Imbalance; Nutritional and Metabolic Diseases; Hypertension; Hypernatremia
• Other Study ID Numbers: SunwayU

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: The principal investigator will make the data available on reasonable request

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No