Why your weight jumps two kilos overnight

You did everything right, and the scale is up 1.8 kg. You did not gain 1.8 kg of fat overnight — that would require eating roughly 14,000 kcal above maintenance. What changed is almost entirely water and gut content.

What the daily number is made of

• Glycogen and its water. Each gram of stored carbohydrate holds roughly three grams of water, so a high-carbohydrate day can add a kilo or more with no change in fat mass.
• Sodium. A salty meal shifts water retention for a day or two.
• Food still in transit. Yesterday's food has mass until it leaves.
• Training. Hard sessions cause inflammation and fluid retention in the worked muscles — often visible for 24 to 72 hours.
• Hormonal cycles, which can move fluid balance by a kilo or more across a month.

Weighing in consistently

1. Same time of day — first thing in the morning is easiest to repeat.
2. After using the bathroom, before eating or drinking.
3. Same clothing, or none.
4. Every day if you can stand it. More readings make the trend line more honest, not less.

Reading the trend

A smoothed trend line turns a jagged daily chart into something you can actually make decisions from. If the trend has not moved in three weeks and you are trying to lose weight, that is signal. If yesterday was up 900 g, that is not.

IGNYT charts the smoothed 90-day trend rather than the raw daily line, and tracks body fat, lean mass and tape measurements alongside it — because scale weight alone cannot distinguish between the two outcomes you actually care about.

When the scale is the wrong tool

If you are new to lifting or returning after a break, you can gain muscle and lose fat simultaneously, and the scale will sit still for months while your body composition changes substantially. Tape measurements and photographs are the better instrument in that period.