Weight and the menstrual cycle. Why the scales move and how to read them

Weight and the menstrual cycle, what happens

Hormone levels change through the month. In the second half of the cycle, many women hold more water and feel bloated. The NHS page on premenstrual syndrome lists bloating, tiredness and changes in appetite among the common symptoms. None of this means you have gained fat. The number on the scales has simply caught a passing wave.

Cravings before your period

Many women want more sweet or salty food in the days before their period. You do not need to fight it with willpower alone. A few habits help.

• Eat regular meals. The NHS suggests that frequent smaller meals every 2 to 3 hours may help with PMS.
• Plan a filling snack, such as a plain yoghurt with fruit or a handful of nuts. Our page on healthy snacks has more ideas.
• Go easy on salt, which adds to water retention.
• Keep moving. A walk often eases bloating and lifts mood.
• Protect your sleep, as tiredness makes cravings stronger.

When to weigh yourself

The fairest comparison is the same day of each cycle. Many women find the week after their period gives the most stable reading. If you weigh weekly, look at the trend over 2 cycles rather than week by week. A waist measurement taken at the same point each month is also helpful.

Iron and periods

Periods mean a monthly loss of iron. Iron contributes to normal formation of red blood cells and haemoglobin. The NHS page on iron gives 14.8mg a day for women aged 19 to 49, compared with 8.7mg for men. Good sources include red meat, beans, nuts, dried fruit, fortified breakfast cereals and dark green leafy vegetables. Vitamin C increases iron absorption, so a little fruit with these foods helps.

If your periods are heavy or you feel very tired, see your GP. The NHS page on iron deficiency anaemia explains that heavy periods are a very common cause, and it can be treated.

Later, the menopause

As periods change and stop, so do weight patterns. Our page on weight loss and the menopause covers that stage.

At the club in Witney

At Witney Nutrition Club, coaches trained in nutrition support members daily, so a high number before a period is put in context rather than taken as a setback. Your first assessment is free.

This article does not replace advice from your GP or another health professional.