PMS and water retention: why you gain 2 kg before your period
You stuck to your routine for a week, but the scale showed a plus of one and a half kilograms this morning. If your period is 3-5 days away, it’s water. You don’t gain fat overnight: to store a kilogram of fat, you need to eat an extra 7000 kcal. But your body can easily retain a liter of water, and it does so every month on schedule. The section about the cycle is — cycle and hormones.
Where the water comes from
During the luteal phase, progesterone and falling estrogen alter the function of aldosterone — the hormone that retains sodium, and with it, water. Add to this cravings for salty and sweet foods: salt draws in water directly, while carbohydrates do so through glycogen, each gram of which binds 3 grams of water. The result: swollen fingers, heavy legs, a swollen-feeling chest, and an extra 1-2 kg that go away on their own by the 2-3 day of menstruation.
1-2 kg
normal water retention
3 g
of water retained by 1 g of glycogen
7000
kcal — that many extra are needed for 1 kg of fat
day 2-3
of menstruation — when water leaves
What increases swelling
Salty and sweet foods together are the most common cause. Not enough water: when you drink too little, the body holds on to its reserves. Not enough protein — oncotic pressure drops, and water moves into the tissues. Not enough movement: without muscles, lymph does not flow. Poor sleep and alcohol — through cortisol. And, less obviously, overly strict fasting during the luteal phase: stress increases aldosterone. How to gently structure your eating window during these days — fasting and the cycle.
What helps
Water 2-3 liters
Paradoxically, with adequate hydration, the body stops storing water. With lemon and a pinch of salt — electrolytes are lost and need to be replenished.
Magnesium and potassium from food
Avocado, leafy greens, nuts, fatty fish. Magnesium 300-400 mg in the evening relieves swelling and cravings for sweets in most women.
Walking 30-40 minutes
The calf muscles are a pump for the lymphatic system. One walk a day relieves half of the heaviness in the legs.
Meet your protein needs
1,4-1,6 g/kg. Without protein, water moves into the tissues, and no diet can fix this.
Cut out sweets, not salt
Salt is needed on a low-carb diet. What needs to be eliminated is sugar and flour — they retain water through glycogen and insulin.
How to weigh yourself without going crazy
With this method, weigh yourself once a week, during the same phase of your cycle. Compare day 7 of this cycle with day 7 of the previous one, not Monday with Monday. Plus measure your waist circumference and take a photo once a month. Everything the scales show from day 22 to day 3 is noise, and you should not react to it by eating or fasting. If the swelling lasts throughout the entire cycle rather than just a week, check your thyroid and protein intake.
Frequently Asked Questions
Will diuretics help?
No. They remove potassium and magnesium, and the swelling returns more strongly. Water, salt, magnesium, and walking are enough.
Do you also get swelling on a low-carbohydrate diet?
Less than on a regular diet, because there are no glycogen fluctuations. But progesterone is still there — 0,5-1 kg of water before your period will remain.
Why are my breasts sore and swollen?
Progesterone and water retention in the glandular tissue. It goes away with your period. If the pain is severe and constant, see a gynecologist.
Reviewed by Anastasia Zhukova, Fitness Trainer • Author of a Nutrition and Training System • Creator of an AI Personal Support Platform
A human has reviewed this material against the method and real client practice.