Numbers without context do not change behaviour. Here is what protein, fat, and carbohydrates actually do inside your body — particularly relevant for managing hormones, stress, and metabolic health.
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Protein — muscle, satiety & hormones
Protein is the primary building block for muscle tissue and the raw material for many hormones. It is the most satiating macronutrient. Adequate protein directly counteracts the muscle loss that accelerates with declining oestrogen after 35.
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Fat — hormones, brain & nervous system
Dietary fat is the direct precursor to steroid hormones — oestrogen, progesterone, testosterone, and cortisol are all synthesised from cholesterol. A diet chronically low in fat disrupts hormonal production at the source.
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Carbohydrates — energy, cortisol & stress
Carbohydrates are your body’s primary fuel. Restricting them too aggressively elevates cortisol, disrupts thyroid function, and can impair sleep quality. The type matters — whole food carbohydrates vs refined produce dramatically different metabolic responses.
Macros by Goal — What Changes and Why
Weight loss — 35% protein / 35% carbs / 30% fat
Higher proteinModerate carbsAdequate fat
Prioritises protein to preserve muscle mass during a calorie deficit. Aggressive carbohydrate restriction during a deficit elevates cortisol significantly, promoting abdominal fat storage and worsening insulin resistance. Fat maintained at 30% supports oestrogen and progesterone production.
Maintenance — 30% protein / 40% carbs / 30% fat
Balanced proteinHigher carbsAdequate fat
Provides the most metabolic flexibility. Higher carbohydrates support training performance, thyroid function, and mood stability. Well-suited to active people who want to optimise energy, recovery, and hormonal health without a specific body composition goal.
Muscle building — 30% protein / 45% carbs / 25% fat
Adequate proteinHigh carbsLower fat
Higher carbohydrates fuel training sessions and support muscle protein synthesis. Designed for people doing consistent progressive resistance training at least 3 times per week in a calorie surplus.
Macros for Hormonal Health
Note: The following guidance is general and educational. People with diagnosed hormonal conditions including PCOS/PMOS, endometriosis, hypothyroidism, or adrenal dysfunction should work with a registered dietitian to personalise their targets.
During perimenopause (typically ages 40–55)
Declining oestrogen reduces insulin sensitivity. Muscle loss accelerates. Increase protein toward 1.4–1.6g per kg of bodyweight, maintain dietary fat to support hormonal production, and prioritise fibre-rich complex carbohydrates over refined ones. Read more: Signs of Hormonal Imbalance in Women →
For PMOS
PMOS (Polyendocrine Metabolic Ovarian Syndrome) is fundamentally a condition of insulin resistance. Focus on pairing carbohydrates with protein and fat at every meal, prioritising low-glycaemic sources, and avoiding refined carbohydrates and added sugars. Higher protein targets toward 35% of total calories support insulin sensitivity. Read more: PMOS Symptoms and Management →
For stress recovery and high cortisol
Avoid aggressive calorie and carbohydrate restriction simultaneously. Eating adequate carbohydrates at regular intervals blunts the cortisol spike that accompanies fasting and low blood sugar. Read more: Cortisol and Weight Gain →
Activity level check: Most people overestimate their activity level by one category. A desk job plus 3 gym sessions per week is lightly active (1.375) — not moderately active (1.55). One level over-estimate inflates your TDEE by 200–300 kcal. When in doubt, go lower and adjust based on 2–4 weeks of real results.
It predicts BMR within 10% for approximately 80% of healthy adults. It does not account for body composition differences, thyroid conditions, PMOS, or hormonal changes during perimenopause. Use your result as a starting point and adjust based on real results over 2–4 weeks.
Do women need different macros than men?
Yes — meaningfully different in context. Women are more susceptible to the negative effects of aggressive carbohydrate restriction, which can elevate cortisol, disrupt thyroid function, and impair menstrual regularity. Women in perimenopause have significantly different protein and fat requirements due to declining oestrogen.
How long does it take to see results?
Energy levels typically change within 1–2 weeks. Body composition changes are measurable after 4–6 weeks. Give any new macro target a minimum of 4 weeks before adjusting.
Should I count macros every day?
Tracking precisely for 2–4 weeks is valuable for calibration. After that, most people can transition to a looser approach built around a protein anchor at every meal, adequate fat and fibre, and mindful portion sizing for carbohydrate-dense foods.
What if my macros feel too low or too high?
If you feel persistently hungry or fatigued after 2 weeks, add 100–150 calories from protein and carbohydrates. Never reduce below 1,200 calories for women or 1,500 for men without dietitian supervision.
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Formula: Mifflin MD et al. A new predictive equation for resting energy expenditure. American Journal of Clinical Nutrition, 1990. pubmed.ncbi.nlm.nih.gov/2305711
Validation: Frankenfield D et al. Comparison of predictive equations for resting metabolic rate. Journal of the American Dietetic Association, 2005. pubmed.ncbi.nlm.nih.gov/15883556
Protein and age: Volpi E et al. Is the optimal level of protein intake for older adults greater than the RDA? Journal of Gerontology, 2013. pubmed.ncbi.nlm.nih.gov/23459215
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⚠ Medical Disclaimer: This calculator provides general nutritional estimates only. It is not a substitute for personalised advice from a registered dietitian or qualified healthcare professional. Results are based on population-level equations and may not accurately reflect individual metabolic needs. People with diabetes, kidney disease, cardiovascular disease, eating disorders, PMOS, thyroid conditions, or other chronic health conditions must consult a qualified healthcare provider before making significant changes to their diet or macronutrient intake. If you are pregnant or breastfeeding, consult your healthcare provider before using this tool. This calculator does not constitute medical advice and is not intended to diagnose, treat, cure, or prevent any disease or health condition.
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