- Weigh every morning and read every week.
- Expect the scale to move by 1 to 2 percent of your weight, a kilogram or two, from one day to the next, and body fat to move 2 to 3 points, without any fat having changed.
- Log alcohol, hard sessions, illness and the cycle so VT can explain the mornings they move.
- Judge a plan by the 7-day trend over three or four weeks, never by one reading.
Where the wobble comes from
Water, and the things that hold it. Each gram of carbohydrate stored as glycogen in muscle and liver is stored with about three grams of water (Fernández-Elías 2015), so a pasta dinner can add a kilogram by morning and a low-carbohydrate day can shed one, neither of them fat. Salt holds water for a day. Alcohol sheds water first and holds it afterward. A hard session leaves the muscles holding water while they repair, often for two days. A long flight, a hot day, a late meal still in the gut, a missed bowel movement and, in women, the second half of the cycle all add to the morning number. There is a weekly rhythm too: in 80 adults weighed daily for up to 330 days, weight was highest on Sunday and Monday and fell through the week, and the researchers suggested the weekend rise be treated as normal rather than as gain (Orsama 2014).
Why body fat wobbles more than fat does
The scale measures water and infers fat, so all of the above moves its body-fat figure directly; a liter of water is worth about a point. Real fat changes by a few hundred grams a week at the very most.
What this means for a plan
A deficit that works shows as a trend that slopes down through the noise, not as a number that falls every day. A week in which the scale rises after a hard training block, a salty weekend or a period is not a week in which the plan failed. VT's energy engine is built for this: it fits a line through the whole window of mornings, discounts the days you have marked, offsets the cycle, and reports your energy balance as a range; the Weight Loss Plan reads that range.
Sources
- Fernández-Elías VE, et al. Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans. Eur J Appl Physiol 2015;115:1919–26. doi:10.1007/s00421-015-3175-z
- Orsama AL, et al. Weight rhythms: weight increases during weekends and decreases during weekdays. Obes Facts 2014;7:36–47. doi:10.1159/000356147.