Intermittent fasting in women over 40, especially during perimenopause or menopause, can help improve insulin sensitivity, metabolism, and weight control, but it may also influence stress hormones like cortisol and affect estrogen and progesterone balance, sometimes leading to fatigue, sleep issues, or cycle changes if done too aggressively. Safer approaches are gentler schedules like 12:12 or 14:10, while 16:8 may work for some but should be personalized based on energy and hormonal response. To stay balanced, it’s important to eat nutrient-dense meals with enough protein, healthy fats, and fiber, stay hydrated, and avoid extreme calorie restriction, while adjusting or stopping fasting if symptoms like stress, poor sleep, or hormonal imbalance appear.