Women, Muscle, and Body Fat – Rethinking Health Across All Ages
- Brainz Magazine
- Dec 20, 2025
- 4 min read
Written by Essado Cardoso, Qualified Dietitian/Nutritionist, Chef, Acupuncturist, and Intuitive Healer
Gabby Essado is a qualified dietitian/nutritionist, chef, acupuncturist, naturopath, and intuitive healer. She is the founder of Green Salt Movement, integrating science with ancient wisdom, nutrition, Chinese medicine, and embodied therapies to support holistic health.
In modern fitness culture, women are often encouraged to achieve extremely low body fat, under 12 percent, and high muscle, a physique modelled after male athletic ideals. Social media, fitness trends, and athletic ideals celebrate women at body fat levels previously almost exclusive to male athletes.
But for women, fat is not just cosmetic. It is a vital endocrine and metabolic tissue that supports hormones, reproductive function, bone health, and long-term metabolic resilience. Understanding how body fat interacts with physiology is important across all life stages, from young adulthood to postmenopause.
1. Body fat and fertility: Why approximately 18 percent matters for reproductive health
For women of reproductive age, body fat plays a crucial role in estrogen and progesterone production, supporting ovulation and egg quality.
Body fat below 16 to 18 percent can reduce leptin levels, signaling to the hypothalamus that energy availability is low.
This may impair ovulation, shorten the luteal phase, or cause irregular cycles.
Fertility outcomes improve when functional body fat is above approximately 18 percent, ensuring healthy eggs and robust reproductive hormone signaling.
Being extremely lean may look fit, but it can compromise fertility in women planning pregnancy.[1] [2]
2. Low body fat is often fine after menopause
Once a woman is postmenopausal, the ovaries no longer produce eggs, and estrogen comes primarily from fat tissue via aromatization. In this context:
Body fat in the range of 12 to 18 percent can be healthy if muscle mass is adequate and energy intake is sufficient.
Hormonal function related to reproduction is no longer a concern, so lower fat does not impact fertility.
The main priority is maintaining muscle, bone, and metabolic health.
Postmenopause, low but functional fat combined with strong muscle can be protective rather than harmful.[3] [4]
3. Perimenopause and midlife: Balancing fat and muscle
During perimenopause, fluctuating estrogen and declining progesterone make the body more sensitive to energy availability and body composition. Women with very low fat and inadequate muscle may experience:
Hot flashes and night sweats
Sleep disruption and anxiety
Hair thinning and skin dryness
Maintaining moderate fat, approximately 18 to 25 percent, and strong muscle helps buffer hormonal swings and supports metabolic resilience.[5] [6]
4. The problem with man-like physiques
Extremely low body fat and high muscle may look strong, but the hormonal cost can be high:
Estrogen drops because fat tissue is the primary site for estrogen conversion
Progesterone production can falter
Leptin decreases, and the brain perceives low energy availability
Cortisol rises, leading to more stress and inflammation
Menstrual cycles become irregular or absent
Even before perimenopause, women with body fat below 16 to 18 percent may experience fatigue, anxiety, poor sleep, and hormonal depletion if nutrition and recovery are inadequate.
From a Chinese Medicine perspective, this often reflects Kidney Yin and Blood deficiency with Liver Qi tension, signaling that the body is being pushed beyond its natural resilience.
5. Functional body fat across the life span
Healthy, functional body fat differs depending on life stage:
Pre-fertility and reproductive age, approximately 18 to 24 percent, support ovulation and egg quality
Athletic women, 16 to 18 percent, may be functional if energy, nutrition, and recovery are adequate
Perimenopause, approximately 18 to 26 percent, supports hormonal stability and resilience
Postmenopause, 12 to 18 percent can be healthy if muscle mass is maintained
The key is functional fat, not extreme leanness, combined with muscle mass and adequate energy availability.
6. Strength, muscle, and longevity
Regardless of age, muscle and metabolic resilience are more important than simply having low body fat. Muscle:
Supports bone density and joint health
Maintains metabolic flexibility
Reduces inflammation
Protects cardiovascular and cognitive health
A woman with moderate fat and strong muscle is healthier and more resilient than a very lean, depleted woman.
7. Cultural note
Today’s fitness culture encourages women to become more like men in terms of physique. While strength and muscle are essential, chasing body fat below 12 percent is often unnecessary and potentially harmful, especially as women age. True female health balances muscle, moderate fat, and hormonal integrity.
Read more from Essado Cardoso
Essado Cardoso, Qualified Dietitian/Nutritionist, Chef, Acupuncturist, and Intuitive Healer
Gabby Essado is a qualified dietitian/nutritionist, chef, acupuncturist, naturopath, and intuitive healer. With over a decade of international experience, she integrates evidence-based nutrition with Chinese medicine and ancient healing wisdom. Gabby views the body as an intelligent, interconnected system where digestion, hormones, emotions, and energy are deeply linked. She is the founder of Green Salt Movement, a holistic health platform supporting deep, sustainable healing. Her work bridges science, embodiment, and consciousness to restore inner ecology and vitality.
References:
[1] Loucks, A. B., et al. “Effects of low energy availability on reproductive hormones and body composition in women.” Journal of Clinical Endocrinology and Metabolism, Mount Sinai School of Medicine.
[2] Mantzoros, C. S., et al. “Leptin’s role in female reproductive function.” New England Journal of Medicine, University of Colorado Boulder.
[3] Chen, Y.-C., et al. “Lower central fat predicts muscle mass loss in menopausal women.” PubMed.
[4] Journal of Bone and Mineral Research. Associations between lean mass, fat mass, and bone health in postmenopausal women.
[5] Bertoli, S., et al. “Fat mass changes during menopause: A meta-analysis.” PubMed.
[6] Frontiers in Endocrinology. Effects of exercise and resistance training on body composition in midlife and postmenopausal women.
