Article
Why the scale jumps after the weekend
Friday 84.1 kg, Monday 85.4 kg. It looks like a lost weekend. It is almost never fat. Here is what it is instead, and which number to look at.
In short
- Up 1 to 2 kg on Monday is almost always water, salt and digestion.
- Gaining 1.3 kg of fat in two days would take about 10,000 kcal extra.
- Decide by the 7-day average, not by the daily number.
Fat takes far more calories
Fat tissue stores about 7,000 to 7,700 kcal per kilogram. To gain 1.3 kg of fat in two days you would have to eat about 9,000 to 10,000 kcal above your maintenance calories. On top of everything you usually eat. Hardly anyone manages that in a weekend.
What the scale measures instead
Glycogen and water
The body stores carbs as glycogen in muscle and liver. Every gram of glycogen holds about 3 to 4 g of water. After pizza, pasta or cake the stores fill up, and the water rises with them. That alone can add up to 2 kg.
Salt
Restaurant meals and snacks often carry far more salt than your usual week. The body then holds on to more water for a day or two.
What is still in your gut
More food also means more food in your gut. It weighs in the next morning, but it is not tissue.
The pattern is normal
A study analysed the daily weights of 80 adults. Weight was highest on Sundays and Mondays and fell again from Tuesday. The swing evened out most clearly in those who lost weight or held it over time. The authors suggest seeing the swing as normal, not as a gain.
Look at the 7-day average
A single number says almost nothing. The average of the last seven days smooths out water, salt and digestion. Weigh yourself every morning under the same conditions: after getting up, after the toilet, before breakfast.
Only draw conclusions after two to three weeks. If the average rises over that time, the gain is real. If only one day jumps, it is water.
How often to weigh in
Every morning gives the average the most values, and then a single outlier does not matter. If the daily look stresses you, three fixed days a week are enough. Spread them out, for example Monday, Wednesday and Friday. Then the Monday after the weekend is just one of three values.
Sample numbers
What this looks like in Trilluminati
- Friday
- 84.1 kg
- Monday
- 85.4 kg
- 7-day average last week
- 84.6 kg
- 7-day average this week
- 84.5 kg
The daily number jumps by 1.3 kg, the average falls by 100 g. Trilluminati shows you both numbers, and the coach judges the direction, not the day.
What to do after the weekend
- Nothing special. Eat as usual, drink normally, train by plan.
- No starving days to make up for it. They do not clear the water faster and they make the next week harder.
- Plan for it. If the weekend often runs over, eat a little less during the week so the average fits.
One weekend does not change the direction.
Training, food and bodyweight in one place.
Trilluminati shows your sets, your protein and the 7-day average of your bodyweight together. A coach sees all three and tells you what comes next. Free while we build.
Beat last time.
Sources
- Hall K. D. (2008): What is the required energy deficit per unit weight loss? International Journal of Obesity 32, 573 to 576.
- Olsson K. E., Saltin B. (1970): Variation in total body water with muscle glycogen changes in man. Acta Physiologica Scandinavica 80, 11 to 18.
- Kreitzman S. N., Coxon A. Y., Szaz K. F. (1992): Glycogen storage: illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition. American Journal of Clinical Nutrition 56, 292S to 293S.
- Orsama A.-L. et al. (2014): Weight rhythms: weight increases during weekends and decreases during weekdays. Obesity Facts 7, 36 to 47.
If your body swells noticeably or your weight swings for weeks without a reason, get it checked by a doctor. This text is not medical advice. If you have a medical condition, are pregnant or live with an eating disorder, please talk to a doctor first.