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Completed

NCT Number: NCT02674971

Lowering Caloric Density of the Diet

For weight loss to occur, energy intake needs to be reduced to incur an energy deficit. One dietary strategy that may facilitate reducing energy intake and enhancing weight loss is consuming a diet low in dietary energy density (ED). The ED of a given food, defined as the ratio of energy of the food to the weight of the food (kcal/g), is largely determined by water content, but is also affected by fat and fiber. Although the 2010 Dietary Guidelines encourage an eating pattern low in energy density (ED) to manage weight, it is currently not known what the best strategy is for reducing ED in the diet. Eating a greater number of foods low in ED or reducing the number of foods high in ED may reduce overall dietary ED. As ED is believed to reduce intake by allowing a greater weight of food relative to total energy consumed assisting with enhancing feelings of fullness, it is anticipated that either increasing consumption of low-ED foods in the diet alone or combining an increase in consumption of low-ED foods with a decrease in consumption of high-ED foods may be the best strategies for reducing overall dietary ED for weight loss.

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Key information

Conditions

Obesity Behavior Behavior, Animal Body Weight Feeding Behavior Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Healthy Eating and Activity Laboratory, University of Tennessee

Knoxville, Tennessee, 37996, United States

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • 1) age between 18 and 65 years and 2) a body mass index (BMI)7 between 27 and 45 kg/m2.

Exclusion criteria

  • report a heart condition, chest pain during periods of activity or rest, or loss of consciousness on the Physical Activity Readiness Questionnaire (PAR-Q)8 (medical conditions that could limit exercise for safety reasons will be required to obtain written physician consent before participating in the investigation)
  • report being unable to walk for 2 blocks (1/4 mile) without stopping
  • are currently participating in a weight loss program and/or taking weight loss medication or lost > 5% of body weight during the past 6 months
  • report major psychiatric diseases or organic brain syndromes
  • have had bariatric surgery or are planning to have bariatric surgery within the next 4 months
  • intend to move outside of the metropolitan area within the time frame of the investigation
  • are pregnant, lactating, < 6 months post-partum, or plan to become pregnant during the investigation.

Treatment and study plan

Common components of intervention

Behavioral

12-week standard lifestyle intervention for obesity, which consists of weekly meetings. Each meeting will last 60 minutes, with participants attending group meetings specific for their condition. In all meetings, participants will be weighed, homework assignments will be verbally reviewed, and a behavioral lesson will be presented. Basic behavioral lessons, will be similar to those that have been successfully used in the Diabetes Prevention Program (DPP) and Look AHEAD. Topics to be covered in the meetings will focus on the dietary prescriptions and dietary information for each condition, the physical activity goal, energy balance, and behavioral strategies. Each session will conclude with reminding participants of their dietary and physical activity goals, and having participants self-monitor these behaviors every day and implement the behavioral strategies discussed in the session.

Primary outcomes

  1. Dietary: Energy Intake

    Time frame: change from baseline to 12 weeks

    Changes in overall dietary intake and changes per eating bout will be assessed by 3 day (2 weekdays and 1 weekend) food records. To determine dietary variables, each food record will be entered into the Nutrition Data System for Research (NDS-R) software developed by the Nutrition Coordinating Center, University of Minnesota, Minneapolis, Minnesota.

  2. Physical activity

    Time frame: change from baseline to 12 weeks

    Changes in self-reported physical activity will be determined by the Paffenbarger Activity Questionnaire (PAQ).16 This questionnaire yields estimates of the total energy expended in PA per week based on flights of stairs climbed per day, city blocks walked per day, and hours of structured activity acquired within a typical week. The PAQ has been shown to be significantly correlated with an objective measure of PA.

  3. Ecological Momentary Assessment (EMA)

    Time frame: change from baseline to 12 weeks

    (EMA) refers to a collection of methods often used in behavioral medicine research by which a research participant repeatedly reports on symptoms, affect, behavior, and cognitions close in time to experience and in the participants' natural environment. EMA protocol will be conducted over 7 continuous days using both semi-random and event-contingent sampling. Semi-random responses will be collected at varied times within three windows (morning, afternoon, and evening), with three assessments occurring per day triggered by an alarm prompt that signals a 30-minute window for response. Event-based sampling will be used to assess eating bouts. Semi-random sampling will assess consumption cues (i.e. feelings of temptation, fullness, desire to eat, energy level and control over eating), along with feelings of hunger, satiation, and deprivation using a series of 11 questions.

  4. Weight

    Time frame: change from baseline to 12 weeks

    Change in weight will be assessed by an electronic scale, using standard procedures.

  5. Dietary: Grams of Intake

    Time frame: change from baseline to 12 weeks

    Changes in overall dietary intake and changes per eating bout will be assessed by 3 day (2 weekdays and 1 weekend) food records. To determine dietary variables, each food record will be entered into the Nutrition Data System for Research (NDS-R) software developed by the Nutrition Coordinating Center, University of Minnesota, Minneapolis, Minnesota.

  6. Dietary: Energy Density

    Time frame: change from baseline to 12 weeks

    Changes in overall dietary intake and changes per eating bout will be assessed by 3 day (2 weekdays and 1 weekend) food records. To determine dietary variables, each food record will be entered into the Nutrition Data System for Research (NDS-R) software developed by the Nutrition Coordinating Center, University of Minnesota, Minneapolis, Minnesota.

  7. Dietary: Macronutrients

    Time frame: change from baseline to 12 weeks

    Changes in overall dietary intake and changes per eating bout will be assessed by 3 day (2 weekdays and 1 weekend) food records. To determine dietary variables, each food record will be entered into the Nutrition Data System for Research (NDS-R) software developed by the Nutrition Coordinating Center, University of Minnesota, Minneapolis, Minnesota.

  8. Dietary: Fiber

    Time frame: change from baseline to 12 weeks

    Changes in overall dietary intake and changes per eating bout will be assessed by 3 day (2 weekdays and 1 weekend) food records. To determine dietary variables, each food record will be entered into the Nutrition Data System for Research (NDS-R) software developed by the Nutrition Coordinating Center, University of Minnesota, Minneapolis, Minnesota.

  9. Height

    Time frame: baseline

    Height will be assessed by stadiometer, using standard procedures.

  10. BMI

    Time frame: change from baseline to 12 weeks

    Change in BMI (kg/m2) will be calculated from height and weight measures.

Secondary outcomes

  1. Diet satisfaction

    Time frame: 12 weeks

    The Food Acceptability Questionnaires will assess acceptability and satisfaction of diet at 12 weeks. Participants will be asked about ease of following the diet, ease of determining foods to consume to meet dietary goals, and ease of reading food labels to select foods to consume to meet dietary goals (which is all one questionnaire).

Other outcomes

  1. Demographic characteristics

    Time frame: baseline

  2. Compliance

    Time frame: 12 weeks

    Participation will be recorded.

  3. Weight History

    Time frame: baseline

Sponsors and collaborators

Lead sponsor

The University of Tennessee, Knoxville

Other

Registry information

Acronym: Lower CD

Important dates

Study start
2015
Primary completion
2025
Study completion
2025
First posted
Feb 5, 2016
Registry last updated
Jun 9, 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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