The Sleep and Weight Study

Prior treatment

• Starting or changing dosage of sleep medications or selective serotonin reuptake inhibitors (SSRIs) in the past 2 months;
• weight loss medications or medications known to significantly affect weight within the past 2 months (e.g., glucagon-like peptide-1 \[GLP-1\] agonist)
• Current PTSD diagnosis or currently receiving treatment for PTSD;
• Currently or recently (past 6 months) receiving insomnia therapy resembling cognitive-behavioral therapy for insomnia (CBT-I);

Other illness

• Sleep disorders other than insomnia (i.e., sleep apnea, restless leg syndrome, narcolepsy); however, those reporting managed sleep apnea will be included;
• Eating disorder (anorexia nervosa, bulimia nervosa, avoidant/restrictive food intake disorder (ARFID), binge eating disorder (BED)); however, those with stable treated BED or bulimia nervosa, or in stable remission ≥6 months will be included;
• A medical condition that impacts sleep, appetite, dietary intake, or weight (e.g., cancer, prostate hyperplasia; uncontrolled thyroid disease);
• Significant alcohol use issues (Alcohol Use Disorders Identification Test-Concise; Bush et al., 1998; score ≥4);
• Current moderate or severe substance use disorder (self-reported diagnosis or current treatment), or regular (≥weekly) use of cannabis or other non-prescribed substances as a sleep aid;
• Self-reported lifetime diagnosis of bipolar disorder or a psychotic disorder;

Other

• Severe depressive symptoms (Patient Health Questionnaire-8 \[PHQ-8\] ≥20);
• Shift work schedule (defined as regularly working between 10pm-6am) or highly irregular work hours that prevent a fixed sleep/wake schedule
• Being pregnant or intention to become pregnant during the study period, Pregnancy involves substantial changes in weight, appetite, energy intake, and sleep architecture that occur independently of the interventions and would confound both the mechanistic and exploratory weight outcomes. Time-in-bed restriction, a core component of the Sleep Coach app, is also not appropriate during pregnancy. Individuals intending to become pregnant are excluded because pregnancy occurring mid-study would introduce these same confounds and interrupt the intervention within the 3-month observation window.T hese criteria are applied for scientific reasons only; pregnancy status is determined by self-report and no pregnancy testing is performed.
• Caretaking for a newborn (\<3 months old) or recently given birth (past 3 months);Caretaking for a newborn imposes externally driven sleep fragmentation and irregular sleep timing. The early postpartum period is likewise characterized by ongoing changes in weight, appetite, and sleep that are unrelated to the interventions and would confound the study outcomes, and time-in-bed restriction is not appropriate during this period.
• Current enrollment in another weight loss, dietary, or sleep intervention trial

• Age 18-55 years
• Body Mass Index (BMI) ≥30 kg/m²
• At least sub threshold insomnia symptoms, defined as Insomnia Severity Index (ISI) score ≥8
• Fluent in English (reading and speaking) to complete app-based interventions and validated surveys. This small pilot study lacks funding for Spanish-speaking study staff, who would be required for screening, consent, weekly check-ins throughout the intervention, and the qualitative interviews and transcript translation; in addition, the Sleep Coach app (Insomnia Coach) is available only in English, so participants in arms 2 and 3 could not receive the intervention in another language. A future fully powered trial will incorporate bilingual staff and translated intervention materials.
• Owns a smartphone (iOS or Android) compatible with the Food Craving app and Sleep Coach app
• Willing and able to provide written informed consent and to participate in all study procedures (including wearing an actigraphy device for 7-day assessment periods).