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 preference and cravings, 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 preference and cravings, bodyweight and composition, and wellbeing ratings.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
30
During this intervention, participants will receive a Dutch diet with regular energy density, without added umami (MSG)
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.
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.
Department of Human Nutrition, Wageningen University
Wageningen, Gelderland, Netherlands
Food intake (kcal)
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.
Time frame: From start to end of each intervention (day 1-14, day 29-42 and day 57-72).
Dietary satisfaction
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.
Time frame: Measured at day 14 (end) of each intervention.
Appetite and thirst ratings
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.
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).
Taste Preference
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.
Time frame: Measured at day 14 (end) of each intervention.
Food cravings
Food cravings will be measured using the Control of Eating Questionnaire (CoEQ) at the end of each intervention. Differences in food cravings will be compared between the three interventions.
Time frame: Measured at day 14 (end) of each intervention.
Perceived umami taste intensity
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.
Time frame: Measured at day 14 (end) of each intervention.
Fat mass
Changes in fat mass will be measured using Bioelectrical Impedance Analysis (BIA), and compared between the three interventions.
Time frame: Six times during each intervention (day 1, 3, 6, 8, 12 and 14).
Bodyweight
Changes in bodyweight will be measured using a calibrated scale, and compared between the three interventions.
Time frame: Six times during each intervention (day 1, 3, 6, 8, 12 and 14).
Differences in MSG complex syndrome related complaints
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.
Time frame: From start to end of each intervention (day 1-14, day 29-42 and day 57-72)
Difference in adverse events or medication use
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.
Time frame: From start to end of each intervention (day 1-14, day 29-42 and day 57-72)
Difference between change in food intake over time
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.
Time frame: From start to end of each intervention (day 1-14, day 29-42 and day 57-72).
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