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My scale didn’t move for 141 days. My body fat fell from 15.9% to 11.9%.

Weight is the wrong scoreboard if you want to look leaner and keep your muscle. Here’s what can see fat, what can’t, and how soon you can know.

Philipp CannonsFounder of Leanrr

My morning weigh-ins, scans and lifting log, June 7 to October 26, 2023.⁠[1] The squat is my estimated best for one rep. One person’s result. Yours depends on where you start.

From June 7 to October 26, 2023, I stepped on the scale on 109 mornings. The weekly average began at 174.1 lb and ended at 174.3 lb. In between it wobbled by a few pounds, as scales do. When I weighed in two days running, the second number was higher almost half the time.

In the same 141 days, five body-fat scans say I lost 7 lb of fat and gained 6 lb of lean mass. My best squat, estimated from my lifting log, went from 352 to 426 lb.

Judged by my weight, nothing happened for almost five months. I would have called it a plateau and changed something that was working. Most people I talk to want what those months gave me: less fat, with the muscle kept. The number most of us judge by can’t see it.

My smart scale saw less than half of my progress.

The obvious fix is a scale that shows body fat. I had one.

From February 2023 to January 2024, my body-fat scans fell from 26.1% to 9.2%: 16.9 points. Over the same months, my smart scale went from 20.1% to 12.5%: 7.6 points. And even that drop took switching on its “sports mode.”

It read 6.0 points low when I started and 3.3 points high when I finished. Off by the same amount every time would have been fine. Off by a different amount as I changed, it hid more than half of my progress.

Had I gone by the smart scale, I’d have thought I’d done less than half the work. That’s the kind of number that makes people quit.

Across 28 scans over several years, the smart scale missed by 2.7 points on average.⁠[1]

Every tool has eyesight.

A tool can’t see a change smaller than its own wobble. Here is the smallest change in fat each one can see, for someone who weighs 180 lb.

A smart scale can’t see a good month of fat loss. A careful scan can see about ten days of it.⁠[2]⁠[3]⁠[4]

What’s in the number besides fat.

A plain bathroom scale is honest about one thing: your total weight. Fat is one part of it, and the slowest part to move. Try reading it.

Which month lost more fat?

Each dot is one of my morning weigh-ins in 2023. Tap the month you think lost more fat.⁠[1]

Your scale can’t tell fat from pizza.

Your scale adds everything in you into one number. Here’s what else is in it, and how far each one can move it.

  • “I lost 5 lb in my first week!”Your plan’s first week

    Carbs and their water leave first, most on very low-carb diets. Often less than half is fat.⁠[5]⁠[6]

    drops 3–7 lb
  • “One pasta night, and I’m up 2 lb?”A carb-heavy day

    Each gram of carbs your muscles store holds at least 3 g of water, so 100 g adds about 1 lb.⁠[7]

    rises 1–3 lb
  • “I had ramen twice this week. Why am I up?”Saltier days

    After a low-salt week, typical salt added about 2 lb. Cutting back took it off within a week.⁠[8]

    rises about 2 lb
  • “I came home from Europe up 2.9 lb.”A long trip

    That one is me, in 2023. Almost none of it was fat: my scans before and after read 13.5% and 13.4% body fat.

    rises 2.9 lb
  • “I’m up 3 lb, and I didn’t change a thing.”Around your period

    Weight creeps up the week before and peaks in its first days. It’s often 1 lb or less.⁠[9]⁠[10]

    rises up to 4 lb
  • “Did leg day make me heavier?”A hard workout

    By the next morning, your blood holds about 10% more plasma.⁠[11]

    rises about 0.8 lb
  • “I started creatine, and I’m up 2 lb already.”Starting creatine

    Muscles pull in water with it, mostly in the first week.⁠[12]

    rises 1–2 lb
  • “That’s 1 lb of fat, gone for good.”A good week of fat loss

    What you’re after: 0.5 to 1.5 lb a week. It stays gone.

    drops 1 lb

They overlap: a restaurant dinner brings salt, carbs and food at once. The people are made up, except me. The numbers are not.

Everything on that list except the last row is the wobble. When it’s bigger than your fat loss, you make decisions on the wobble.

Three things that can see fat.

You already own the first. The second is free. The third costs money, so use it to check the other two.

The trend, after about 15 mornings.

Dinner comes and goes. Fat loss adds up. So there’s a day when your loss is bigger than the wobble, and from then on the trend on your scale is real.

At a pound a week, weighing in every morning, that’s about day 15. Weighing in once a week, it’s about day 21.⁠[13]

Don’t count week one. Start eating less, and 3 to 7 lb can leave in the first week, often less than half of it fat. It feels like proof, and it isn’t yet.

Is it working?

Probably, but 8 mornings can’t be sure yet. At this pace, your scale needs about 3 more mornings.

It assumes your scale swings about 1.2 lb from one morning to the next, as mine does. Nothing you type leaves this page.

Your lifts.

While my scale sat still, the most I could lift kept climbing. A flat scale with rising lifts is a hint that something is changing that the scale can’t see. And if your weight is dropping while your lifts hold, that’s a good sign your muscle is holding too.

Lifts can fool you too. Lose fast enough, and strength can hold for a while as muscle shrinks. That’s what the third one is for.

One careful body‑fat scan, every month or two.

A DEXA scan is a low-dose X-ray you lie under. It’s the only one of the three that sees fat directly, and it’s what told me the 141 flat days were working.

Make it twice as sharp: use the same machine, go in the morning before you eat or drink, and eat and train the same way the day before.

What not looking cost me: 26 days of tracking every meal, 0 lb of fat lost.

In January 2023 I started carefully. I aimed for a small deficit, 200 to 300 calories a day, because I was afraid of losing muscle. I tracked every meal and weighed in every morning.

On February 5, my scan read 26.1%, up from 25.7%.

The answer had been on my phone for two weeks. By January 21, my weigh-ins were already sure I was gaining, not losing.⁠[13] I had the numbers. I wasn’t reading the trend.

The cause was small: a little extra cooking oil. Two tablespoons is about 240 calories,⁠[14] enough to erase a deficit that size.

Window
Jan 11 to Feb 5, 2023
Impact
26 days of tracking every meal. Body fat went from 25.7% to 26.1%: 1.3 lb of fat gained.
Detected
Feb 5, by a body-fat scan.
Detectable
Jan 21, from weigh-ins already on my phone.
Causes
A deficit small enough for cooking oil to erase. No one reading the trend.
Status
Fixed. 26.1% to 11.9% by that October.

Misread the scale, and it costs you one of three ways. You quit something that was working. You stick with something that isn’t. Or you push so hard you lose muscle instead of fat.

What looking got me: 33 lb of fat in 263 days, with the scale up on 84 mornings.

I started at 206 lb and 26.1% body fat. Between my scans on February 5 and October 26, 2023, I lost 33 lb of fat. Every square below is one of the 263 mornings in between. The orange ones are mornings the scale went up from the day before: 84 of the 209 I could compare, or 4 in every 10.

Any orange square could have been the morning I decided it wasn’t working. Because I was reading the trend, my lifts and a scan about once a month, none of them was. And when the scale stopped in June, I knew to keep going.

One person’s result. Yours depends on where you start.

Fat loss has two speed limits.

Once you can see fat, you can steer. There are two limits to steer between, and both have a number.

MAX5%of your fata week

The most you can lose and keep your muscle.

Your fat can only release so much energy a day: about 31 calories for each pound of fat, by one well-known estimate.⁠[15] Leanrr sets the fastest safe speed a little under that, at about 5% of your fat a week. Go faster, and your body makes up the gap from muscle.

Find your fastest safe speed

Your body fat

0 lb a week2 lb4 lb
Slower than neededSafeMuscle loss zoneFastest safe: 2 lb a week

Safe zone

Your fat can supply this. With enough protein, lifting and sleep, what you lose is mostly fat.

Check with your doctor before a fast cut.

MIN7daysto know

The soonest you can know it’s working.

The faster you lose, the sooner your loss is bigger than the wobble. At 2.5 lb a week, my own scale was sure in about 7 days. That’s the floor. Here is the day your scale can be sure at slower speeds, weighing in every morning.⁠[13]

The two limits meet. Your fastest safe speed is also the one that tells you soonest.

Keep your weekends.

If you love going out on the weekend, the answer isn’t to stop. It’s to eat a bit less on the days you care about less, so the week still adds up. Your weigh-in average tells you within two or three weeks whether it worked. Then you adjust the numbers, not your willpower.

See an example week

Big meals out each weekend

Big meals out on Friday and Saturday. Eat about 400 calories less Monday to Thursday, and the week still averages 2,000 calories a day.

An example week averaging 2,000 calories a day, where a big meal out adds about 800 calories to that day.

Start tomorrow, by hand.

You don’t need Leanrr for any of this. A bathroom scale and a notes app will do.

1
Every morning: weigh in.

Do it after the bathroom, before you eat or drink. Read the 7-day average, not the day.

2
Every workout: log your lifts.

If your lifts hold while your weight drops, that’s a good sign your muscle is holding.

3
Every month or two: one careful scan.

Use the same machine, in the morning. It checks the other two.

Give it 15 mornings before you judge anything, more if you’re losing slower than a pound a week. And don’t count week one.

What Leanrr does with your numbers.

By hand, you can tell whether it’s working. You can’t tell why Tuesday jumped or what to change next, and reading it every morning is the part people stop doing. In 2023 I rebuilt Leanrr to do that reading for me. Today it’s an AI fitness & nutrition coach for busy people.

What it reads
It reads your morning weigh-ins, photos of what you eat, your watch’s workouts and sleep, and your lifts. Each of them lies a little, so Leanrr makes them catch each other.
What it asks of you
Each day, you weigh in and snap a photo of what you eat.
What it tells you
Every Sunday, it tells you how much fat came off that week and gives you one change to try. It says “Not sure yet” until your food photos and your scale agree.
Your first week
Before you pay, you see your fastest safe pace and the date you could hit your goal. Then you weigh in and take photos for seven mornings. If your first Sunday says “Not sure yet,” you now know why.
What you don’t need
You don’t need a gym or a body-fat scan to start. Weigh-ins and food photos are enough, and lifts or a scan make the answer surer.
What it costs
It costs $99 a month on iPhone, with a 30-day money-back guarantee, no questions asked.

An example of the Sunday answer.

See how fast you can lean out

See your plan before you pay.

Or book 15 minutes with Philipp
Sources
  1. My own records: body-fat scans (DEXA) and smart-scale readings since 2016, and my morning weigh-ins and lifting log for 2023. Lifts are my best estimated one-rep max each month. leanrr.com/case-file/001/
  2. Siedler MR et al. Assessing the reliability and cross-sectional and longitudinal validity of fifteen bioelectrical impedance analysis devices. Br J Nutr. 2023;130(5):827–840. doi.org/10.1017/S0007114522003749
  3. Zemski AJ et al. Same-day versus consecutive-day precision error of DXA body composition in resistance-trained athletes. J Clin Densitom. 2019;22:104–114. doi.org/10.1016/j.jocd.2018.10.005
  4. Slater GJ et al. Impact of 24-hr diet and physical activity control on short-term precision error of dual-energy X-ray absorptiometry physique assessment. Int J Sport Nutr Exerc Metab. 2023;33(1):30–38. Least significant change for fat mass 0.63 kg (1.4 lb). doi.org/10.1123/ijsnem.2022-0125
  5. Hall KD et al. Calorie for calorie, dietary fat restriction results in more body fat loss than carbohydrate restriction in people with obesity. Cell Metab. 2015. PubMed 26278052. Six days at about 800 fewer calories a day: 2.9 to 4.1 lb lost, but only 0.5 to 1.0 lb of it fat. doi.org/10.1016/j.cmet.2015.07.021
  6. Yang MU, Van Itallie TB. Composition of weight lost during short-term weight reduction. J Clin Invest. 1976. PubMed 956398. On 1,200 calories a day, the men lost 6.3 lb in 5 days, 69% of it water. On 800-calorie diets, water was 37% (mixed diet) to 61% (very low carb) of the loss. doi.org/10.1172/JCI108519
  7. 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. At least 3 g of water stored per gram of glycogen. doi.org/10.1007/s00421-015-3175-z
  8. Heer M et al. Increasing sodium intake from a previous low or high intake affects water, electrolyte and acid-base balance differently. Br J Nutr. 2009. PubMed 19173770. Nine men on a metabolic ward: going from low to typical salt added 2.2 lb in 6 days, and going back to low salt took 2.4 lb off. doi.org/10.1017/S0007114508088041
  9. Watson PE, Robinson MF. Variations in body-weight of young women during the menstrual cycle. Br J Nutr. 1965. PubMed 14290862. Weight rose through the week before a period and peaked in its first days. Just over half of the swings stayed within 1.1 lb; the largest, 3.9 lb, came the week before a period. doi.org/10.1079/bjn19650023
  10. White CP et al. Fluid retention over the menstrual cycle: 1-year data from the prospective ovulation cohort. Obstet Gynecol Int. 2011. PubMed 21845193. Women’s own ratings of fluid retention rose from around ovulation and peaked on the first day of their period. doi.org/10.1155/2011/138451
  11. Gillen CM et al. Plasma volume expansion in humans after a single intense exercise protocol. J Appl Physiol. 1991. PubMed 1761491. Six young men did eight 4-minute hard cycling intervals. The next morning their plasma volume was 10% higher, and they weighed 0.37 kg (0.8 lb) more, mostly as extra plasma. doi.org/10.1152/jappl.1991.71.5.1914
  12. Kreider RB et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. J Int Soc Sports Nutr. 2017. PubMed 28615996. Loading held about 0.5 to 1 liter of extra water, in line with the weight gained. doi.org/10.1186/s12970-017-0173-z
  13. Leanrr’s analysis of my 2023 morning weigh-ins, Nov 2026: how many days a steady loss takes to be bigger than the wobble (95% sure), simulated with my day-to-day swing of about 1.2 lb, the median of 2,100 runs per pace. Weighing daily, 1 lb a week took about 15 days and half a pound a week about 23 days. Weighing weekly, they took about 21 and 35 days. My real weigh-ins took about as long at the same pace. In January 2023, my weigh-ins were 95% sure I was gaining by Jan 21, fifteen days before the scan that confirmed it.
  14. U.S. Department of Agriculture. FoodData Central: Oil, olive, salad or cooking. FDC ID 171413. 884 calories per 100 g, and a tablespoon is 13.5 g: about 119 calories, so two tablespoons is about 240. fdc.nal.usda.gov/food-details/171413/nutrients
  15. Alpert SS. A limit on the energy transfer rate from the human fat store in hypophagia. J Theor Biol. 2005;233(1):1–13. About 31 calories per pound of fat per day. doi.org/10.1016/j.jtbi.2004.08.029

Characters adapted from “Avatar Illustration System” by Micah Lanier (source, CC BY 4.0), made with DiceBear.