"My metabolism has slowed" is one of the most common things people say after 40. The truth is more encouraging than the myth.

What actually changes

• Muscle mass: without strength training, adults gradually lose muscle, which slightly reduces energy use.
• Activity: busier careers and family life often mean less incidental movement.
• Sleep and stress: both tend to worsen in midlife and affect appetite.
• Hormones: perimenopause and menopause can shift fat distribution and sleep for many women.

Large studies of energy expenditure suggest that metabolic rate, adjusted for body size, stays remarkably stable through mid-adulthood. Much of the "slowdown" comes from less muscle and less movement — both of which you can influence.

What works

1. Strength training two to three times a week to preserve and build muscle.
2. Higher protein: around 1.2–1.6g per kg of body weight, spread across meals.
3. Steps: protect your daily movement, especially during a diet.
4. Sleep routines: consistent bed and wake times.
5. A moderate deficit: aim for 0.5% of body weight per week to protect muscle.

Mealify learns your personal maintenance calories from your own data rather than relying on age-based formulas — useful if you suspect the standard numbers don't fit you. If you have a medical condition or are going through menopause, your GP can advise on anything specific to you.