Foods Within a Meal and Food Liking Study

  • End date
    Dec 29, 2022
  • participants needed
  • sponsor
    The University of Tennessee, Knoxville
Updated on 3 March 2022
body mass index
Accepts healthy volunteers


For weight loss to occur, energy intake needs to be reduced to incur an energy deficit. One dietary strategy that may facilitate weight loss is consuming a diet low in dietary energy density (ED). It is hypothesized that a diet low in ED, which can be achieved by a high intake of low-ED foods, low intake of high-ED foods, or a combination of the two, will allow a greater amount of volume of food to be consumed relative to energy consumed, which can assist with reducing energy intake.

To understand how best to lower the ED of the diet, it is important to understand the relationship between low-ED and high-ED foods. Behavioral economics is a framework that provides a foundation to understand that eating behaviors can be substitutes for each other. Substitute eating behaviors are two behaviors that change in the opposite direction of each other (i.e. one behavior increases as the other behavior decreases). If low-ED and high-ED foods are substitutes for each other, in situations in which low-ED food intake increases, high-ED food should automatically decrease, and vice versa. If they are not substitutes, when low-ED food intake increases, high-ED food intake should remain unchanged, and when high-ED food intake decreases, low-ED food intake should remain unchanged. When low-Ed and high-ED foods are not substitutes for each other, purposeful change in intake for both low- and high-ED foods need to occur to best lower dietary ED.

Thus, the purpose of this study is to investigate if low-ED foods and high-ED foods substitute for each other. Healthy weight adults will be served a meal over 4 sessions, with each meal containing 5 different food items. The foods in the meal will vary in ED: low-ED = 0 to 1.0 kcal/kg; medium-ED = 1.1 to 2.9 kcal/kg; high-ED = > 3.0 kcal/g. For the 4 sessions, the meals will include: 1) 3 low-ED foods, 0 medium-ED foods, 2 high-ED foods; 2) 3 low-ED foods, 1 medium-ED food, 1 high-ED food; 3) 1 low-ED food, 2-medium ED foods, 2 high-ED foods; and 4) 1 low-ED food, 3 medium-ED foods, and 1 high-ED food.


All participants will be asked to come to Healthy Eating and Activity Lab (HEAL) for 1, 60-minute screening session and 4, 30-minute meal sessions, with no more than two meal sessions occurring per week between the hours of 11:00am and 7:00pm. For each participant, each meal session will need to occur within the same two-hr time frame (i.e., all meal sessions occurring between 11am and 1pm). During the first session interested participants will sign the consent form. After signing the consent form, eligibility will be confirmed by taking height and weight measures and confirming liking of foods, using a 100mm visual analogue scale (VAS). Participants will also be given questionnaires related to demographics. Prior to attending their meal session, participants will be asked to not change their typical eating pattern in the day prior to their session (including eating before 10 am), but to not eat within 3 hours of their session, and to not engage in physical activity for 24 hours prior to the session.

For the remaining four sessions, at the start of the session the participant will be asked to recall all foods and beverages consumed 24 hours prior to the scheduled appointment. During this recall if a participant reports consuming any foods or beverages besides water within 3 hours of the appointment, the appointment will be rescheduled. Participants will also be asked if they have participated in any physical activity 24 hours prior to their scheduled appointment. If the participant answers "yes," then the appointment will be rescheduled.

After completing hunger, fullness, and liking of foods questionnaires, participants will be presented with one of the four variations of meals. Each meal consists of a total of 1,500kcals of five of the following items: chicken noodle soup (Low-ED), sugar-free chocolate pudding (Low-ED), red seedless grapes (Low-ED), macaroni and cheese (Medium-ED), strawberry yogurt (Medium-ED), vanilla ice cream (Medium-ED), pretzels (High-ED), or graham crackers (High-ED). Following the presentation of the meal, participants will be instructed to taste each foods and that they will have 25 minutes to eat as much or as little as they would like of the meal provided. At the completion of 25 minutes, the lunch will be removed and the participant will be asked to complete a scale for evaluating levels of hunger, fullness, and liking of the foods. The participant will also be scheduled for a subsequent session the following week at a similar time. Upon completing all 5 sessions, participants will receive a $25 gift card.

Condition Diet Habit, Obesity
Treatment Order 1, Order 2, Order 3, Order 4
Clinical Study IdentifierNCT03783507
SponsorThe University of Tennessee, Knoxville
Last Modified on3 March 2022


Yes No Not Sure

Inclusion Criteria

age between 18 and 35 years
body mass index (BMI) 18.5 to 24.9 kg/m2
unrestrained eater (12 on Three Factor Eating Questionnaire (TFEQ)
report liking chicken noodle soup, chocolate sugar-free pudding, grapes, strawberry yogurt, macaroni and cheese, vanilla ice cream, pretzels, and graham crackers (rate all items 50mm on a visual analogue scale (VAS)
report regularly eating before 10 am; and 6) can complete all sessions within 8 weeks of the screening session, will be eligible for the study

Exclusion Criteria

report binge eating
report a medical condition that influences eating
report allergies to foods used in the investigation
currently smoke
report dietary restrictions
report taking a medication that affects appetite
report being pregnant or breast-feeding
report being an athlete in training
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Additional screening procedures may be conducted by the study team before you can be confirmed eligible to participate.

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If you are confirmed eligible after full screening, you will be required to understand and sign the informed consent if you decide to enroll in the study. Once enrolled you may be asked to make scheduled visits over a period of time.

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Complete your scheduled study participation activities and then you are done. You may receive summary of study results if provided by the sponsor.

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