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While eating the majority of energy earlier in the day appears to have a positive effect on weight and cardiometabolic outcomes, it is not clear how eating earlier in the day influences other behaviors that have a circadian rhythm (sleep), other energy balance behaviors important for weight loss (physical activity), and self-reported feelings of appetite control (hunger and fullness). Thus the purpose of this study is to examine the influence of timing of eating on sleep patterns, physical activity, and self-reported feelings of appetite control. It is hypothesized that those who eat the majority of their calories earlier in the day will have greater weight loss than those who eat the majority later in the day.
Thirty adults will be provided an 8-week standard lifestyle intervention, that includes a 1200-1500 kcal/day, < 30% energy from fat dietary prescription, and a physical activity goal of 200 minutes/week. Participants will be randomized to one of two conditions differing in timing of energy consumed during eating bouts. Both conditions will limit the number of eating bouts/day to three. Participants will be instructed to eat their first eating bout within one hour of awakening and to consume their second and third eating bouts within five or six hours of their previous bout. Participants will be discouraged from eating at least one hour prior to going to sleep. During the intervention, participants will be instructed to self-monitor the time they wake up, the time of the start of each eating bout, and time they go to bed, as well as foods and beverages, and portion sizes, consumed. One condition will consume more energy earlier in the day (MORNING), thus energy intake will be split amongst the three eating bouts with 50% in the first bout, 30% in the second bout, and 20% in the last bout. The second condition will consume more energy later in the day (EVENING), thus energy intake will be split amongst the three eating bouts with 20% in the first bout, 30% in the second bout, and 50% in the last bout.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| MORNING | Experimental | Participants will be instructed to consume 50% of their energy intake in their first eating bout, 30% in their second eating bout, and 20% in their third eating bout. For example, a participant prescribed a 1200 kcal/d diet needs to consume 600 kcal in their first eating bout, 360 kcal in their second bout, and 240 kcal in their third bout. Participants will be provided with sample meal plans meeting this prescription. |
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| EVENING | Experimental | Participants will be instructed to consume 20% of their energy intake in their first eating bout, 30% in their second eating bout, and 50% in their third eating bout. For example, a participant prescribed a 1200 kcal/d diet needs to consume 240 kcal in their first eating bout, 360 kcal in their second bout, and 600 kcal in their third bout. Participants will be provided with sample meal plans meeting this prescription. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Eat majority of calories in the morning | Behavioral |
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| Eat the majority of calories in the evening |
| Measure | Description | Time Frame |
|---|---|---|
| weight | Weight will be assessed by an electronic scale, and height will be assessed using a stadiometer, using standard procedures, with participants wearing light clothing, without shoes. BMI (kg/m2) will be calculated from these measures. | 0 and 8 weeks |
| Measure | Description | Time Frame |
|---|---|---|
| physical activity | the SenseWear® armband from BodyMedia will measure physical activity-related energy expenditure for the course of the study. Energy expenditure will be calculated using the corresponding software. This armband reports physical activity in total minutes and joules expended. Furthermore, this armband reports minutes of physical activity divided into 5 categories: sedentary activities (<1.5 METS), light physical activity (1.5-2.9 METS), moderate activity (3.0-5.9 METS), vigorous activity (6.0-8.9 METS), and very vigorous activity (≥9.0 METS). Minutes of active energy expenditure are also reported, which includes total number of minutes engaged in moderate, vigorous, or very vigorous activity. For each participant, mean minutes of sedentary, light, moderate, and vigorous activity (vigorous activity + very vigorous activity) will be calculated over the course of the 7 days. |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Hollie Raynor, Ph, RD | University of Tennessee | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Univeristy of Tennessee--HEAL Lab | Knoxville | Tennessee | 37996 | United States |
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| Label | URL |
|---|---|
| HEAL research information website | View source |
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| ID | Term |
|---|---|
| D050177 | Overweight |
| D009765 | Obesity |
| D015431 | Weight Loss |
| ID | Term |
|---|---|
| D044343 | Overnutrition |
| D009748 | Nutrition Disorders |
| D009750 | Nutritional and Metabolic Diseases |
| D001835 | Body Weight |
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| Behavioral |
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| 0 and 8 weeks |
| sleep | participants will be instructed to wear the SenseWear® armband from BodyMedia® on their upper left arm for 7 days. Participants will be instructed to wear the armband for 23 hours a day for each of the 7-day time frames. The SenseWear® has been shown to be a reliable measurement for total sleep time in both individuals with and without obstructive sleep apnea. The SenseWear® armband recognizes the onset of sleep when there is a drop in the heat flux sensor (arm skin temperature).16 The BodyMedia® software then codes the output from the SenseWear® as either wake or sleep (regardless of sleep stage) binary codes,15 based on manufacturer sleep algorithms.16 The armband reports total minutes of lying down and total minutes wake/sleep during the lying down time, allowing sleep efficiency to be calculated. For each participant, minutes of sleep per 24 hrs and mean sleep efficiency will be calculated from the 7 days of measures. | 0 and 8 weeks |
| diet | Energy and macronutrient intake overall and per eating bout will be assessed by 3 day (2 weekdays and 1 weekend) food records. Eating bouts will only be counted if at least 25 kcals were consumed. All foods and beverages, eaten within 1/2 h of the start of a meal, will be counted as a single eating bout. 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. | 0 and 8 weeks |
| feelings of hunger and fullness | EMA protocol will be conducted over 7 continuous days using both semi-random and event-contingent sampling. 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. Event-based sampling will assess these same cues and feelings, as well as reasons for initiating and terminating eating, Time-based and event-based sampling questions will be programmed and displayed using Satellite Forms™ MobileApp Designer software (Thacker Network Technologies Inc., Alberta, Canada). | 0 and 8 weeks |
| D012816 |
| Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D001836 | Body Weight Changes |