Last updated: September 2026
Quick Summary:
- Week 5 of my comeback: the scale jumped to 83.7 kg (184.5 lbs), up 1.4 kg (3.1 lbs) in a week, mostly water weight from one big family celebration dinner heavy on carbs and sweets.
- Waist at the navel came in at 93.6 cm (36.9″), under the 94 cm (37 in) scoreboard target on this page for the first time in this log, even in the same week the scale spiked.
- Visceral fat index held at 6, unchanged from 2 scans ago, and body fat ticked down to 15.6% from 15.7%. Average intake for the week landed at 2,007 kcal and 173 g protein, both up from 1,910 kcal and 166 g the week before.
Week 5 of my comeback delivered the biggest single-week scale jump in this log, 1.4 kg (3.1 lbs), most of it water weight from one big family celebration dinner that ran heavy on carbs and something sweet at every course. It also delivered a waist reading under my own 94 cm (37 in) scoreboard target for the first time, and a visceral fat index that hasn’t moved in a month. Those two facts sitting in the same week are the actual story here, not the number on the scale by itself.
If you’re new here, the full context is in the comeback log and the plan I’m following is in the 10-week cutting plan.
What week 5 actually looked like
I did not follow the plan on the Saturday night before this check-in. One big family celebration dinner, plenty of carbs, sweet dishes at every turn, and no attempt to log it or work around it. I moved my usual Sunday-morning measurement to Monday morning to let the dust settle a day, and the scale still surprised me: 83.7 kg (184.5 lbs), the sharpest single-week rise since I started this log on August 9.
What didn’t slip: training. I hit all 4 sessions this week, and 2 of them were my first runs inside the FitnessForties app I’ve been building, as its first everyday user. That’s the actual headline of week 5, buried under a scale number that grabbed all the attention for the wrong reasons.
My first instinct was to read the jump as fat gain and treat the week as a setback. It isn’t, or at least the fuller data doesn’t support that reading, and the rest of this post is the honest version of why.
Why the scale jumps after one big meal: water weight and what it doesn’t mean
A carbohydrate-heavy meal replenishes glycogen, and glycogen doesn’t store on its own: each gram of glycogen is bound to roughly 3 g of water in the body (Murray & Rosenbloom, 2018). A big dinner that pushes several hundred extra grams of carbohydrate through your system in one sitting can plausibly add a kilogram or more of scale weight in glycogen and its bound water alone, before any food or fat is even counted. This isn’t a new finding: a classic 1970 study in Acta Physiologica Scandinavica tracked total body water rising and falling in step with muscle glycogen changes decades before “water weight” became a diet-culture talking point (Olsson & Saltin, 1970).
The fat-gain math tells the same story from a different angle. Storing 0.45 kg (1 lb) of actual body fat takes roughly a 3,500 kcal surplus over maintenance. One dinner, even a genuinely large one, rarely clears that bar by more than a fraction, and I don’t have a number to put on this specific dinner because I didn’t log it. Even in the worst case, most of a 1.4 kg jump after one meal is not going to be fat.
I want to be honest about where this explanation gets messier, though, because an objective log doesn’t get to skip the inconvenient data point. My body water percentage on this week’s scan actually read down, not up, from the last reading, which isn’t the clean confirmation a tidy “it’s all water weight” story would want. Single-point bioimpedance hydration readings are noisy for the same reasons scale weight is noisy: timing, recent food, recent training, all move the number. I’m not going to over-read one water percentage any more than I’d over-read one scale weight. The stronger evidence sits in the next section: visceral fat, body fat, and lean mass all moved the right direction or held flat in the same week the scale spiked. That’s a harder pattern to explain away as a coincidence than a single soft data point.
The numbers: week 5 of the comeback
| Metric | Week 4 (Sep 6) | Week 5 (Sep 14) | Change |
|---|---|---|---|
| Weight | 82.3 kg (181.4 lbs) | 83.7 kg (184.5 lbs) | +1.4 kg (+3.1 lbs) |
| Waist (at navel) | 94.2 cm (37.1″) | 93.6 cm (36.9″) | -0.6 cm (-0.2″) |
| Chest | 109.1 cm (43.0″) | 109.6 cm (43.1″) | +0.5 cm (+0.2″) |
| Right arm | 34.9 cm (13.7″) | 34.8 cm (13.7″) | -0.1 cm |
| Left arm | 35.3 cm (13.9″) | 35.1 cm (13.8″) | -0.2 cm |
| Sessions | 3 of 4 ✗ | 4 of 4 ✓ | |
| Avg calories | 1,910 | 2,007 | +97 |
| Avg protein | 166 g | 173 g | +7 g |
This also happened to be scan week, 2 weeks early against the usual cadence, since I had the full Hume readout in hand anyway and a real number beats waiting for a tidy schedule:
| Scan metric | Week 5 reading (Sep 14) |
|---|---|
| Body fat | 15.6%, down from 15.7% at the last scan |
| Skeletal muscle | 44.0 kg, up from 43.9 kg |
| Visceral fat index | 6, unchanged for the 2nd straight scan |
| Torso and leg fat | 14.9% torso, 10.3-10.9% legs, both rated low |
| BMI | 25.2, flagged “high” by the app; see the caveat below |
| Goal weight | 78 kg (172 lbs), 5.7 kg (12.6 lbs) to go |
The scan also claims a metabolic age of 35 against my real 47, same as every scan so far. I don’t put much faith in that number and I’d rather you didn’t either; I report it once here for completeness and won’t be tracking it.
What the scan says that the scale doesn’t
Here’s the correction I owe this page: earlier this week I flagged a 90.3 cm waist reading from my tape app as a milestone, before I’d matched it against this log’s own protocol. This page measures the waist at the navel, and the app’s “waist” field and its “abdomen” field are not the same point on the body; the abdomen reading, 93.6 cm (36.9″), is the one consistent with 5 weeks of readings that have moved from 96.3 cm down in small, believable steps, not a sudden 3.9 cm drop that would be an outlier by any standard. 93.6 cm is still real progress, and still the first reading under the 94 cm target on this page’s own scoreboard. It just isn’t the more dramatic number I reached for first. Same lesson this log keeps teaching: check the source before you celebrate the number.
BMI reads 25.2 this week, back over 25 and flagged “high” by the app. I’d give that flag exactly as much weight as it deserves for someone carrying 65.9 kg of lean mass at a 78.7% lean mass rate, which is not much. BMI can’t distinguish muscle from fat, and this scan’s own regional breakdown, torso and leg fat both rated low, is a more honest read on body composition than a height-to-weight ratio built for a population average.
What changes next week
The FitnessForties app is now a real part of this log instead of a plan for later, and I’m not going to render a verdict on 2 sessions in. That would be exactly the kind of premature reading I’ve spent this whole post arguing against. Next Sunday’s check-in, September 20, is where this week’s water weight explanation gets tested against real data too: if this was mostly glycogen and water, the scale should drift back toward the pre-dinner trend over the next several days. If it doesn’t, that’s worth reporting too.
Frequently asked questions
Why did my weight jump after one big meal?
Most of a fast, single-meal weight jump is glycogen and the water bound to it, not fat. Each gram of glycogen your body stores comes with roughly 3 g of water, so refilling glycogen after a carbohydrate-heavy meal can add a kilogram or more of scale weight within a day, well before any fat storage would show up.
How long does water weight from a big meal last?
In my experience and based on how glycogen and its bound water behave, it typically clears within a few days once eating returns to your normal pattern. A single high-carb dinner is not a standing change to your glycogen stores, it’s a temporary refill.
Does visceral fat change after one big meal?
No. Visceral fat index is a slower-moving, structural marker, not something that shifts from a single dinner. My own reading held at 6 across this week’s scan and the one before it, while the scale moved by over a kilogram in the same window.
Is BMI accurate for someone who lifts weights?
Not reliably. BMI only accounts for height and total weight, so it can’t separate muscle from fat. At 78.7% lean mass, my own BMI of 25.2 reads “high” on a metric that has no way to see what’s actually carrying that weight.
Final thoughts
The whole point of a public log is that it survives a week like this one intact: the highest single-week scale jump so far, mostly water weight, sitting next to a waist reading under target and a visceral fat number that hasn’t budged. Read only the scale and it’s a bad week. Read the full page and it’s closer to a non-event with one honest missed night attached to it. That’s the case for logging all of it, not just the flattering half.
References
- Murray, B., & Rosenbloom, C. (2018). Fundamentals of glycogen metabolism for coaches and athletes. Nutrition Reviews, 76(4), 243-259.
- Olsson, K. E., & Saltin, B. (1970). Variation in total body water with muscle glycogen changes in man. Acta Physiologica Scandinavica, 80(1), 11-18.
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