Age-adjusted calculation

TDEE Calculator for Women Over 40

Women over 40 experience hormonal changes that reduce metabolic rate and shift fat distribution. This calculator uses the Mifflin-St Jeor equation to estimate your TDEE accurately, helping you set realistic calorie targets that account for the metabolic changes that come with age.

Mifflin-St Jeor equation · Age-adjusted calorie targets
No signup required Age-adjusted calculation Instant results
Your gender
Your height
Your weight
Your calorie targets
Maintenance
—
kcal / day
Keep your weight stable at this level
Fat Loss
—
kcal / day
−400 kcal · steady, sustainable pace
Moderate Deficit
—
kcal / day
−500 kcal · ~0.45 kg/week
Your BMR — Calories burned at complete rest
Gentle deficit (−300 kcal) — ~0.27 kg/week · hormone-friendly pace
Calculated using the Mifflin-St Jeor equation
These estimates are for informational purposes only and are not medical advice. Consult a registered dietitian or healthcare professional for personalised guidance.
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How Metabolism Changes After 40

After 40, women experience several hormonal and physiological changes that reduce TDEE:

Declining oestrogen — Lower oestrogen reduces lean muscle mass (which drives BMR) and increases fat storage, particularly around the abdomen. This shift begins before menopause.

Reduced muscle mass — Without targeted resistance training, adults lose 3–5% of muscle mass per decade after 30. Less muscle means a lower BMR and TDEE.

Metabolic adaptation — The body becomes more efficient with calories over time, meaning the same food intake that maintained weight at 30 may cause gradual weight gain at 45.

Example — woman at age 45, 68 kg, moderately active:

BMR = (10 × 68) + (6.25 × 165) − (5 × 45) − 161 = 1,382 kcal/day

TDEE = 1,382 × 1.55 = 2,142 kcal/day

Gentle fat loss = 2,142 − 400 = 1,742 kcal/day

Your Personalised Calorie Targets

Nutrition Strategy for Women Over 40

The most important nutritional adjustments for women over 40 are:

Higher protein: Aim for 1.6–2.0 g per kg bodyweight to combat muscle loss. This is significantly higher than general guidelines. Focus on chicken, fish, eggs, dairy, legumes, and tofu.

Smaller deficits: Restrict to 300–400 kcal below TDEE rather than aggressive 500–750 kcal deficits. Larger deficits worsen hormonal disruption, increase cortisol, and accelerate muscle loss in peri- and post-menopausal women.

Resistance training priority: 3–4 sessions per week of resistance training is the single most effective intervention for maintaining muscle mass, bone density, and metabolic rate after 40. Cardio alone is insufficient for preserving body composition.

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The main TDEE tool for all ages with maintenance, fat loss, and muscle gain targets.
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Compare your Basal Metabolic Rate across three formulas including Mifflin-St Jeor.

Frequently Asked Questions

Why does metabolism slow down after 40 for women? +
After 40, women experience declining oestrogen levels which reduce muscle mass and increase fat storage, particularly around the abdomen. BMR decreases by roughly 1–2% per decade after 30, meaning a woman who needed 2,000 kcal at 30 may need only 1,800–1,900 kcal at 45 with the same activity level.
How many calories should a woman over 40 eat to lose weight? +
Most women over 40 do well with a deficit of 300–500 calories below their TDEE — a more moderate approach than younger women because crash diets worsen hormonal imbalance and muscle loss. Use this calculator to find your TDEE, then subtract 300–500 kcal for steady fat loss.
Does perimenopause affect TDEE? +
Yes. Perimenopause typically begins in the mid-to-late 40s and causes declining oestrogen that further slows metabolism, disrupts sleep (which affects hunger hormones), and increases fat storage. Women in perimenopause often need 100–200 fewer calories than their calculated TDEE suggests, so adjust based on your real results over 4 weeks.
What exercise is best for women over 40 to boost TDEE? +
Resistance training is the most effective way to maintain and increase TDEE after 40 because it preserves muscle mass. Aim for 3–4 sessions per week. Combine with 150 minutes of moderate cardio weekly. Avoid relying solely on cardio as it can accelerate muscle loss when combined with a deficit.
Should women over 40 eat more protein? +
Yes. Women over 40 benefit from higher protein intake of 1.6–2.0 g per kg bodyweight to combat age-related muscle loss (sarcopenia). This is higher than general adult guidelines. Spreading protein across 3–4 meals also improves absorption and muscle protein synthesis in older adults.