Period Weight Gain, Explained
Every month, the same story: the week before your period, the scale jumps and every diet thought in your head starts arguing. Here's what's actually happening — and how to stop the monthly panic.
Hormones move water
In the days before a period, shifts in estrogen and progesterone make the body retain more sodium — and therefore more water. Add in slower digestion and bloating, and the scale can read 1–2 kg heavier without a gram of fat gained.
The typical pattern
- Retention builds across the late luteal phase — the week before bleeding.
- It commonly peaks around the first day of the period.
- It releases over the following few days.
- The pattern repeats — which makes it predictable, and ignorable.
Cravings pile on
Premenstrual appetite genuinely increases — energy needs rise slightly and cravings rise more. If you eat a bit more that week, that's normal too; it takes roughly 7,700 extra calories to gain a single kilo of fat, and a few heavier days don't get close.
How to track through it
Keep weighing daily and let the trend absorb the wave. Better yet, compare like with like: your weight this cycle-week versus the same week last cycle. If that comparison is flat or falling, you're maintaining or losing — whatever the pre-period spike claims.
Common questions
- How much weight do you gain on your period?
- Typically 1–2 kg (2–4 lb) of water weight, peaking around the first day of bleeding. Some people notice barely any; a few hold more. It releases within a few days.
- When does period weight gain go away?
- Usually within 3–5 days after your period starts, as hormone levels shift and your kidneys release the retained sodium and water.
- Should I weigh myself during my period?
- Yes, if daily weighing is your habit — skipping days just leaves holes in your trend. Log the reading, expect the spike, and judge progress cycle-over-cycle instead of against last week.
Ready to start? Open the app page: Weight trend tracker.