Time-restricted Eating in Peri- and Postmenopausal Women

The overall objective of the study is to examine the effect of an 8-hour time-restricted eating intervention on lipid levels and body composition in peri- and recently postmenopausal women with untreated dyslipidemia.

This is a randomized controlled trial investigating the effects of an 8-TRE intervention compared to ad libitum eating (control) on metabolic health and body composition in recently postmenopausal women with untreated dyslipidemia. Following a 1-week baseline assessment, participants will be randomized to either a TRE or unrestricted control diet schedule (1-to-1 ratio) for 8 weeks. At baseline and weeks 4 and 8 of the intervention, daily eating and sleep patterns will be assessed for one week, followed by collection of fasting lipids and metabolic labs, body weight and vital signs; questionnaires assessing sleep and mood health, actigraphy and body composition via whole-body dual-energy x-ray absorptiometry will be assessed at baseline and week 8.

Eligibility Criteria:
Inclusion Criteria:

* Healthy women aged 40-58 years
* Perimenopausal or recently postmenopausal, \>1 year and \<5 years
* BMI \> 30 kg/m2
* Dyslipidemic, defined as the presence of one or more lipid-based cardiovascular disease risk-enhancing factors per American College of Cardiology/American Heart Association guidelines
* Normal renal and hepatic function
* Perimenopausal women, a negative pregnancy test

Exclusion Criteria:

Dietary factors:

* Diagnosis, or strong clinical suspicion, of eating disorders, including but not limited to, anorexia nervosa, bulimia nervosa, binge eating disorder
* Concurrent dietary intervention or modification unrelated to study procedures

Psychiatric factors:

* Current major depressive episode
* Suicidal ideation
* Lifetime history of bipolar disorder, psychosis, or other serious mental health problem
* Current alcohol/substance use disorder

Medical factors:

* Use of lipid-lowering or lipid-enhancing medications
* Use of systemic hormonal (estrogens and/or progestin) therapies
* Use of weight loss medications or supplements
* Use of medications that may cause weight loss or gain, unless body weight and medication usage remained stable for at least 6 months
* Previous weight loss surgery
* Abnormal vital signs at screening visit
* Body weight \> 350 pounds, per DXA scan limits
* Malignancy within past 2 years
* Major surgery within past 3 months
* Medical instability considered to interfere with study procedures
* Contraindications to DXA scanning
* Use of medications that have the potential to cause hypoglycemia (e.g., insulin, sulfonylureas)
* Undergoing treatment for cancer
* Use of medications for which time-restricted eating would interfere with recommended timing of medication ingestion with food intake.

Lifestyle and other factors:

* Irregular sleep/wake schedule
* Shiftwork
* Recent travel across 2 or more time zones
* Recent change in exercise habits
* Work or social schedules that would impede ability to adhere to study protocol

Adherence factors:

-Inability to adhere to study procedures completed between screening and randomization visits

Off-Study Criteria:

* Initiation of new medications for lipid management, weight loss, hormonal medications, or other medications that may cause changes in weight or lipid levels
* Development of any significant medical problem
* Enrollment in another clinical trial involving study procedures or medications that might interfere with study procedures.
* Significant deviation from study protocol or protocol violation
* Inability to adhere to time-restricted eating window