The purpose of this investigation is to conduct a 12-week pilot study to examine the effect of three different dietary prescriptions that differ on targeting reducing energy density (kcal/gram) and energy (kcal) on overall dietary intake, hunger, feelings of deprivation, satisfaction with the diet, mood, and weight loss in 45 overweight/obese adults receiving a 12-week behavioral weight loss intervention.

Given the current prevalence of overweight and obesity among adults in the United States and the projected increase of these conditions in the future, development of effective weight loss and weight loss maintenance strategies is imperative. For weight loss to occur, energy intake needs to be reduced to incur an energy deficit, and for successful weight loss maintenance, energy intake needs to remain lower than energy intake at pre-weight loss levels due to an overall reduction in body size which reduces basal metabolic rate. One dietary strategy that may facilitate weight loss maintenance is consuming a diet low in dietary energy density (ED). This pilot study will test the effects of a dietary prescription focused on ED.

All participants in the investigation will receive a standard 12-week behavioral obesity intervention. The intervention will include an activity goal that participants will gradually work to achieve over the course of the 12-week intervention along with standard behavioral weight loss strategies. One condition will receive a dietary prescription for weight loss that focuses solely on lowering the ED of the diet, another condition will receive the traditional dietary prescription used in behavioral weight loss interventions that reduces energy intake, and the third condition will receive both prescriptions. Pre and post intervention measurements will be taken to determine if there are differences between groups.

Inclusion Criteria:

• Age between 21 and 65 years
• Body mass index (BMI) between 25 and 45 kg/m2

Exclusion Criteria:

• Report a health condition on the Physical Activity Readiness Questionnaire (PAR-Q)
• Report being unable to walk for 2 blocks (1/4 mile) without stopping
• Report major psychiatric diseases/organic brain syndromes via a phone screen
• 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
• Intend to move to another city within the time frame of the investigation
• Are pregnant, lactating, less than 6 months post-partum, or plan to become pregnant during the time frame of the investigation
• Have had gastric surgery for weight loss