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NCT Number: NCT07438028

Energy Reduction and Umami

People tend to regulate intake by the weight of food rather than its energy content, making energy dense foods, especially those combining salty, fatty, and umami tastes, more likely to promote passive overconsumption. Lowering energy density can reduce daily energy intake, but often decreases palatability, whereas umami can enhance palatability, and sometimes decrease food intake. This suggests that adding umami to a regular energy dense diet could reduce food intake over time, and that adding umami to a reduced energy dense diet could sustain palatability and limit compensatory energy intake. Therefore, the aim of this study is to assess the effect of a 2-week dietary intervention of adding umami and/or lowering energy density on food intake. Secondary objectives are whether adding umami and/or lowering energy density affect dietary satisfaction, appetite, perceived umami intensity, food preferences, bodyweight and composition, and wellbeing ratings.

This will assessed in a double-blind crossover, randomized controlled trial of three times two weeks, each separated by two weeks washout in 33 healthy Dutch adults between 18-65 years of age, with a BMI between 20-30. Umami taste will be added through MSG supplementation of the three main meals. Supplementation will depend on both intervention group, and individual participants' body weight. Energy density will be lowered by swapping regular products for low-fat, low-sugar or higher water products.

The three intervention diets will vary in umami taste intensity, and/or energy density: 1) regular energy density without added umami (control), 2) regular energy density with added umami, 3) reduced energy density with added umami. Umami will be supplemented by supplementing food items with 55-60 mg MSG per kg bodyweight daily, divided over three eating occasions. Foods will be offered ad libitum, and participants will add a seasoning sachet containing MSG to their selected portion.

The primary objective will be to compare average daily food intake (kcal) over two weeks between the three dietary interventions differing in umami taste intensity and energy density. Secondary outcomes are dietary satisfaction, appetite, perceived umami intensity, food preferences, bodyweight and composition, and wellbeing ratings.

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Key information

Conditions

Sensory Testing Energy Density Food Intake Measurement Umami Taste

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy: as judged by the participant;
  • Age 16-65 years at the time of inclusion, assessed by date of birth;
  • Proper understanding of the Dutch language, as questionnaires will be in Dutch;
  • Able to visit Wageningen University, as required for dietary intervention and testing;
  • Body mass index 20-30 kg/m2;
  • Having normal taste ability, assessed using Mueller taste strip test, ≥12 out of 20 assessed correctly.

Exclusion criteria

  • Suffering from endocrine- or gastro-intestinal diseases or other diseases that might influence study outcomes (such as diabetes, Crohn's disease, cardiovascular disease, hypertension, etc.);
  • Diagnosed with eating disorders (currently or in the past);
  • Diagnosed with taste or smell disorders in the past six months;
  • Pregnant or lactating during the study intervention;
  • Following a strict dietary regime;
  • Extreme physical activity (>10 hours per week moderate/high intensity exercise);
  • Gain or loss of more than 5 kgs in the last six months prior to study entry;
  • Suffering from lack of appetite for any reason;
  • Use of medication that may influence the appetite (medication will be judged by the medical investigator);
  • Having a food allergy and/or intolerance for foods used in the dietary intervention (e.g. lactose intolerance, gluten intolerance, MSG sensitivity). This will be assessed with an open question;
  • Consumes more than 14 (women) or 21 (men) glasses of alcohol per week;
  • Consumes MSG-rich sauces (soy sauce, ketjap and/or curry paste) more than once per day, or consumes more than 3 savoury food items (paprika chips, instant noodles, sundried tomatoes and/or pre-packaged seasonings) per day. This will be assessed with a frequency of consumption table;
  • Irregular eating pattern. This will be measured with a frequency of meal/food consumption table, and is defined as: frequency of breakfast consumption less than once per week;
  • Unwilling to maintain regular exercise pattern during the study period. This will be assessed with a yes/no question;
  • Unwilling to quit use of soft or hard drugs during the intervention;
  • Student or personnel of the division of Human Nutrition and Health, Wageningen University;
  • Participating in any other intervention study/studies or planning to participate in another intervention study during the study period.

Treatment and study plan

Regular energy density, no added umami

Other

During this intervention, participants will receive a Dutch diet with regular energy density, without added umami (MSG)

Other names: regED/-MSG

Regular energy density, with added umami

Other

During this intervention, participants will receive a Dutch diet with regular energy density, with added umami (MSG). Added umami will represent Dutch MSG intake levels of around the 95th percentile, which is about 55-60 mg/kg body weight.

Other names: regED/+MSG

Lowered energy density, with added umami

Other

During this intervention, participants will receive a Dutch diet with lowered energy density, with added umami (MSG). Energy density will be lowered by substituting regular products for lower-fat, lower-sugar or higher water versions. Added umami will represent Dutch MSG intake levels of around the 95th percentile, which is about 55-60 mg/kg body weight.

Other names: lowED/+MSG

Primary outcomes

  1. Food intake (kcal)

    Time frame: From start to end of each intervention (day 1-14, day 29-42 and day 57-72).

    Difference between interventions in daily food intake, averaged over two weeks. Food intake is defined as total daily energy intake from meal, snack and drink consumption. Food intake will be measured by weighing breakfast, lunch and dinner intake in grams, which will be converted to energy (kcal). Snack and drink consumption will be recorded and converted to energy (kcal) as well. Food intake is measured daily, and averaged over each intervention.

Secondary outcomes

  1. Dietary satisfaction

    Time frame: Measured at day 14 (end) of each intervention.

    Difference in dietary satisfaction scores between interventions, measured with the dietary satisfaction questionnaire (DSat-45). Difference between dietary satisfaction scores will be compared between the three interventions.

  2. Appetite and thirst ratings

    Time frame: From start to end of each intervention (day 1 to day 14, day 19 to day 42 and day 56 to day 70).

    Appetite and thirst ratings will be measured six times daily (before three main meals and at three random times each day). Difference between average appetite and thirst ratings will be compared between the three interventions.

  3. Taste Preference

    Time frame: Measured at day 14 (end) of each intervention.

    Preference for sweet/fa, sweet, salt/fat and salt tastes will be measured using PrefQuest at the end of each intervention (day 14). Differences of preferences for these tastes will be compared between the three interventions.

  4. Perceived umami taste intensity

    Time frame: Measured at day 14 (end) of each intervention.

    Perceived umami taste intensity will be measured at the end of each intervention during a sensory test, during which participants will rate their perceived umami taste intensity of samples differing in food type (solid, semi-solid, liquid) and MSG concentration. Differences in perceived umami taste intensity will be compared between the three interventions.

  5. Fat mass

    Time frame: Six times during each intervention (day 1, 3, 6, 8, 12 and 14).

    Changes in fat mass will be measured using Bioelectrical Impedance Analysis (BIA), and compared between the three interventions.

  6. Bodyweight

    Time frame: Six times during each intervention (day 1, 3, 6, 8, 12 and 14).

    Changes in bodyweight will be measured using a calibrated scale, and compared between the three interventions.

  7. Differences in MSG complex syndrome related complaints

    Time frame: From start to end of each intervention (day 1-14, day 29-42 and day 57-72)

    MSG syndrome complex related complaints will be assessed daily using an MSG tolerance questionnaire. Number of reported complaints in differences of MSG complex syndrome related complaints will be compared between the three interventions.

  8. Difference in adverse events or medication use

    Time frame: From start to end of each intervention (day 1-14, day 29-42 and day 57-72)

    The difference in Adverse events occurence, or medication use between intervention groups at the end of each intervention, adjusted for baseline differences. This will be measured daily by a questionnaire.

  9. Difference between change in food intake over time

    Time frame: From start to end of each intervention (day 1-14, day 29-42 and day 57-72).

    Difference between interventions in the day-to-day pattern of food intake across the two-week intervention periods. Food intake is defined as total daily energy intake from meal, snack and drink consumption. Food intake will be measured by weighing breakfast, lunch and dinner intake in grams, which will be converted to energy (kcal). Snack and drink consumption will be recorded and converted to energy (kcal) as well. Food intake is measured daily, and averaged over each intervention.

Other outcomes

  1. MSG consumption

    Time frame: From start to end of each intervention (day 1-14, day 29-42 and day 57-72)

    MSG will be administered based on intervention group and bodyweight of each individual participant. Daily MSG consumption will be measured by asking participants to return empty sachets that contained the MSG supplementation. Differences in MSG consumption between the interventions will be reported as a compliance measure.

  2. Sex

    Time frame: Baseline (day 0)

    Based on self-report in the screening questionnaire. Baseline characteristic.

  3. Age

    Time frame: Baseline (day 0)

    Based on self-report in the screening questionnaire. Baseline characteristic.

  4. Height

    Time frame: Baseline (day 0)

    Will be assessed using a stadiometer as the average of two measurements, rounded to the closest decimal. This will be done during the physical screening session.

  5. Baseline medicine usage

    Time frame: Baseline (day 0)

    Based on self-report in the screening questionnaire. Baseline characteristic.

  6. Smoking status

    Time frame: Baseline (day 0)

    Based on self-report in the screening questionnaire. Baseline characteristic.

  7. Dietary restraint score

    Time frame: Baseline (day 0)

    Measured by the Dutch Eating Behaviour Questionnaire (DEBQ).

  8. Dietary taste patterns

    Time frame: Baseline (day 0)

    Measured by Food Frequency Questionnaire designed to classify people on taste consumption patterns (tasteFFQ). Results will be used to describe habitual food intake based on taste (relative food intake in grams of each taste) at baseline.

  9. Physical activity level

    Time frame: Measured at day 14 (end) of each intervention.

    Measured using the SQUASH questionnaire with a reference period of two weeks. This is a compliance measure as participants are asked to maintain stable exercise patterns during the study period. Physical activity will be reported as a along with descriptive measures of participant characteristics.

Study contacts

Contact information is provided by the study sponsor or research team.

Merel J. van der Kruijssen, Msc

CONTACT

[email protected]

+31 6 1289431

Monica Mars, Dr. Ir.

CONTACT

[email protected]

Sponsors and collaborators

Lead sponsor

Wageningen University

Other

Collaborators

  • Ajinomoto Co., Inc.

Registry information

Official study title

Interactive Effects of Umami Taste Intensity and Energy Density on Longer Term Food Intake

Acronym: Season

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Feb 27, 2026
Registry last updated
May 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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