Overview

This study is aimed at women currently going through menopause, either as part of the natural process (physiological menopause), or following hormonal treatment for breast cancer. There are several ways of slowing the weight gain frequently encountered in this situation, reducing the intensity of menopause-related symptoms and improving quality of life in this context.

In this trial, the investigators examine the efficacy and possible adverse effects of intermittent fasting compared with a control intervention. Participation lasts 14 weeks, with an optional 12-month follow-up. Study participants are randomly assigned to either the intervention group or the control group. In the intervention group, study participants fast for 16 hours per day and eat over a period of 8 hours (intermittent fasting often called time-restricted eating \[TRE\] 16h/8h). In the control group, the usual eating pattern is continued for 12 weeks.

The main objective of the study is to evaluate the efficacy of TRE in terms of weight and fat loss, improvement in metabolic profile, menopausal symptoms and bone health. In addition, the study team closely monitors any adverse effects.

Eligibility

Inclusion Criteria:

• Women with confirmed physiological menopause without current anti-cancer treatment (group A), or women with menopausal symptoms in the context of aromatase inhibitors used as adjuvant therapy for hormone-sensitive non-metastatic breast cancers regardless of physiological menopause before the cancer diagnosis (group B)
• Age 40-65 years
• Body mass index 25-40 kg/m2
• Stable weight (± 2 kg) over the previous month
• Eating window ≥ 12 hours (self-reported and measured during the run-in phase)
• Able to give informed consent and follow the study procedures for the entire duration
• Confident use of a smartphone and able to take regular pictures of food/drinks

Exclusion Criteria:

• On a hypocaloric restrictive diet, intermittent fasting or in a weight management program over the previous month
• Previous bariatric surgery or planned during the study
• Active eating disorder(s) or major mental illness at inclusion
• Psychoactive treatment with recent or planned changes of drug compound or dosage
• Treatments affecting body weight (e.g. glucocorticoids, GLP-1 receptor analogues)
• Diabetes with hypoglycemic drug(s) will be excluded, however those with prediabetes (as defined by the American Diabetes Association) or diabetes with no risk of hypoglycemia (i.e. treated with non-hypoglycemic drugs or without medication) will be included
• Active metabolic bone diseases (e.g. Paget disease, osteomalacia), however women with osteoporosis will be included
• Shift work comprising night shifts (working between 11pm and 6am) over the previous 2 weeks or planned during the study
• Travel/trip to a different time zone (≥ 2-hour time difference) over the previous 2 weeks or planned during the study
• Enrolled in another interventional clinical trial (medication, surgery, medical device) over the previous 2 weeks or planned during the study