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Why is the scale not moving? What’s happening when you’re losing inches

If your clothes fit better and the tape measure says smaller, but the scale hasn’t moved, you’re very likely still making progress. Body weight is the total of everything in you, and most of what moves it from day to day isn’t fat.

By the Shapen team at Minimaapps · Published · Reviewed · How we write about health

The short answer

  • Weight moves by about half a kilo from one morning to the next, even when nothing has changed.
  • It also follows a weekly rhythm: highest early in the week, lowest by Friday.
  • Water travels with stored carbohydrate, so a change in routine can move the scale by more than a kilo without any change in fat.
  • Muscle and fat can change at the same time, so the scale can stay flat while your shape changes.
  • So judge progress over weeks, and by more than one number: your waist, your photos and your weekly average weight.

Your weight moves every day, and most of it is water

Even under controlled conditions, body weight isn’t still. In a study of 65 active men weighed first thing every morning, weight varied by an average of 0.51 kg from day to day (Cheuvront et al., 2004).

What moves is mostly not fat. When researchers measured what made up two-week weight changes in 46 adults living normally, about 84% of the change was fat-free mass, mostly water, rather than fat (Bhutani et al., 2017).

A single weigh-in, then, mostly tells you how much water, food and everything else you’re carrying that morning.

There’s a weekly rhythm too

Weight also has a week-long pattern. In 80 adults who weighed themselves daily, weight was highest on Sunday and Monday and drifted down through the week. The lowest point fell on Friday or Saturday in 60% of cases (Orsama et al., 2014). The authors’ conclusion is worth repeating: weekend-to-weekday swings “should be considered as normal instead of signs of weight gain”.

A larger European study of 1,421 adults tracking their weight found the same rhythm, about 0.35% of body weight across the week. It also measured a rise of about 1.35% over Christmas, which took months to fade (Turicchi et al., 2020).

If you weigh in on Monday one week and Friday the next, you can see a “change” that is only the day of the week.

Water travels with stored carbohydrate

Your muscles store carbohydrate as glycogen, and glycogen is stored with water: about 3–4 grams of water for every gram (Olsson and Saltin, 1970; Fernández-Elías et al., 2015). In one study, refilling glycogen stores raised body weight by 2.4 kg, almost all of it water.

So a harder training week, a rest week, travel or a change in routine can move the scale by a kilo or more, in either direction, without a gram of fat changing.

Muscle and fat can change at the same time

When you train with resistance, you can build muscle while you lose fat. A review of strength-training research summed up ten weeks of training as roughly 1.4 kg more lean weight and 1.8 kg less fat (Westcott, 2012).

That’s a change of more than 3 kg in what your body is made of, and the scale would show it as a loss of 0.4 kg. This is body recomposition, and it’s why the scale is a poor judge of it. More on that in how to tell if body recomposition is working.

What to track instead

The scale isn’t useless; it’s noisy. Pair it with signals that respond to shape rather than water.

  1. Your waist. Measure it weekly, at the same time of day. The World Health Organization’s method is to measure midway between your lowest rib and the top of your hip bone, at the end of a normal breath out, twice; if the two readings are within 1 cm, use the average (WHO, 2008). A shrinking waist with a steady weight is one of the clearest signs of recomposition.
  2. Progress photos. One a week, in the same spot, light and pose. Photos show changes that numbers miss, as long as they’re taken the same way each time: see how to take progress photos that line up.
  3. A weekly average, not a single weigh-in. Weigh at the same time on several mornings and compare one week’s average with the next. That smooths out the daily and weekly swings above.
  4. A longer window. Compare four to eight weeks, not four to eight days. Real changes in fat and muscle are slow; water is fast.

How your clothes fit and what you can lift are signals too. If the tape, the photos and your training are moving in the right direction, a flat scale isn’t a stall.

How Shapen helps

Shapen was built around this problem. You take one photo a week, and last week’s outline sits over the camera so the pose and distance match. You log weight, waist and your other measurements beside each photo, and each number gets its own chart, so a falling waist line can sit next to a flat weight line. With Shapen Pro you can put any two weeks side by side.

Shapen doesn’t set calorie targets or give diet advice, and this guide doesn’t either.

When to talk to a doctor

Ordinary swings are just that. But a weight change you can’t explain, swelling in your legs or ankles, or weight changes alongside feeling unwell are worth raising with a GP or doctor.

References

  1. Cheuvront SN, Carter R, Montain SJ, Sawka MN. Daily body mass variability and stability in active men undergoing exercise-heat stress. Int J Sport Nutr Exerc Metab. 2004;14(5):532–540. https://doi.org/10.1123/ijsnem.14.5.532
  2. Bhutani S, Kahn E, Tasali E, Schoeller DA. Composition of two-week change in body weight under unrestricted free-living conditions. Physiol Rep. 2017;5(13):e13336. https://doi.org/10.14814/phy2.13336
  3. Orsama A-L, Mattila E, Ermes M, van Gils M, Wansink B, Korhonen I. Weight rhythms: weight increases during weekends and decreases during weekdays. Obes Facts. 2014;7(1):36–47. https://doi.org/10.1159/000356147
  4. Turicchi J, O’Driscoll R, Horgan G, et al. Weekly, seasonal and holiday body weight fluctuation patterns among individuals engaged in a European multi-centre behavioural weight loss maintenance intervention. PLoS ONE. 2020;15(4):e0232152. https://doi.org/10.1371/journal.pone.0232152
  5. Olsson K-E, Saltin B. Variation in total body water with muscle glycogen changes in man. Acta Physiol Scand. 1970;80(1):11–18. https://doi.org/10.1111/j.1748-1716.1970.tb04764.x
  6. Fernández-Elías VE, Ortega JF, Nelson RK, Mora-Rodriguez R. Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans. Eur J Appl Physiol. 2015;115(9):1919–1926. https://doi.org/10.1007/s00421-015-3175-z
  7. Westcott WL. Resistance training is medicine: effects of strength training on health. Curr Sports Med Rep. 2012;11(4):209–216. https://doi.org/10.1249/JSR.0b013e31825dabb8
  8. World Health Organization. Waist circumference and waist–hip ratio: report of a WHO expert consultation, Geneva, 8–11 December 2008. Geneva: WHO; 2011. https://www.who.int/publications/i/item/9789241501491