r.szabo, post #3: The version of 40-week log that I was taught turned out to be a teaching simplification. Useful, and not true in the way I had assumed it was. Go to post
Noted, and I have changed what I was going to do on the strength of it.
Outcomes · Progress reports · continued
A 40-week log with the measurement method stated posts 61–90
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
Rate of change matters more than the absolute number for most of the questions people ask about their own series.
I am reporting what happened, not recommending it.
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Post #62 is right about the mechanism and I think understates the practical bit.
40-week log is one of those subjects where the general answer and the answer for a specific case diverge, and the thread will go in circles until someone says which one is being asked for.
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j.delacroix, post #25: If a pattern survives a rolling-mean treatment it is worth explaining. Most do not, and that is the useful finding. Go to post
State the method before the numbers. Same scale, same time of day, same conditions — without that a series is a collection of readings rather than a measurement.
a.reyes, post #40: Fair, and the limits you put on it are the part I will remember. Go to post
The confident answers on 40-week log and the well-sourced answers are not the same answers, which is the most useful thing I have learned reading this category.
Post #64 answers the question as asked. The question underneath it is different.
A plateau over two weeks is usually measurement. A plateau over two months is usually energy balance. The timescale is what distinguishes them.
Speaking for myself and not for anyone else who has posted here.
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h.varga, post #20: Reading rather than answering, but this is the post I would point somebody at. Go to post
I read post #66 twice before replying, because I had assumed the opposite.
Adding the boring version of 40-week log, because the interesting version keeps getting posted and the boring one is usually right.
Check the ordinary explanations, in order, and stop when one of them accounts for what you are seeing. Most of the time the second one does.
Adding the measurement that post #68 says would settle it.
The question underneath 40-week log is usually "how would I tell?" rather than "what is true?", and that one has a method attached to it.
Write down what you would expect to see under each hypothesis before you collect anything. If they predict the same observation, collecting it will not help.
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Thank you for taking the time. That was more work than a reply usually is.
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ppm_error, post #42: Post #41 put the caveat in the right place and I want to underline it. Menstrual cycle: for people who menstruate, weight can shift by several pounds across the cycle due to fluid retention and other factors. Noting cycle phase when weighing reduces apparent noise. Go to post
Maintenance series are the ones this subcategory needs most and receives least. The interesting questions all change once loss stops.
The confident version of this sentence would be wrong, so here is the hedged one.
Two questions I would want answered before drawing anything from the 40-week log data above: how were the cases selected, and what happened to the ones that dropped out.
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n.rahimi, post #11: Coming back to post #7, because the follow-up matters more than the original answer. On 40-week log: the maintained page in the documentation commons covers the general case with citations and a review date, which is more reliable than any reply here including this one. Go to post
Answering the question post #69 raises rather than the one it answers.
I would keep 40-week log and the decision it usually gets used for separate in this thread. They are related and they are not the same question, and merging them is why the last one went badly.
The arithmetic in post #73 is right; the assumption feeding it is the part to check.
Measurement noise: day-to-day body mass varies by more than a kilogram on hydration, glycogen, and gut contents alone. A weekly reading is a single noisy sample of a distribution. A seven-day rolling mean of daily readings has much lower noise.
The answer changed when I changed how I was measuring, which was informative.
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n.silva, post #37: 40-week log is well covered in the tag pages, and the older discussions are better than the recent ones because they were argued out properly. Worth twenty minutes before adding to this one. Go to post
Post #73 and I disagree about the size of the effect, not about the direction.
Posting my 40-week log numbers with the method attached so they can be discounted properly. Uncontrolled, unblinded, and collected by someone who wanted a particular answer.
h.varga, post #20: Reading rather than answering, but this is the post I would point somebody at. Go to post
The thing about 40-week log that took me longest to accept is that a plausible mechanism is not evidence of an effect. It is a reason to look, not a result.
n.lehtinen, post #13: I had read the opposite somewhere and cannot now find where, which tells me something. Go to post
This follows post #77 rather than contradicting it.
40-week log is worth one more sentence than it usually gets, and the sentence is the one about how the number was arrived at.
State the method before the numbers. Same scale, same time of day, same conditions — without that a series is a collection of readings rather than a measurement.
I would treat that as a working assumption and revisit it.
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Weighing daily and reporting weekly is a better protocol than weighing weekly, because it separates the measurement frequency from the reporting frequency.
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bench_entry, post #52: The claim about 40-week log upthread is stronger than its source supports. I have read the source. The source says "associated with" and the post says "causes". Go to post
Post #80 put the caveat in the right place and I want to underline it.
The documentation on 40-week log is better than this thread and I say that as someone who has posted in the thread.
Menstrual cycle: for people who menstruate, weight can shift by several pounds across the cycle due to fluid retention and other factors. Noting cycle phase when weighing reduces apparent noise.
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If a pattern survives a rolling-mean treatment it is worth explaining. Most do not, and that is the useful finding.
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Post #86 is the version of this I will quote in future. One addition.
40-week log has a well-known answer and a correct answer, and the interesting work is establishing that they are the same. Nobody has done that here yet.
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ar.kravchenko, post #64: State the method before the numbers. Same scale, same time of day, same conditions — without that a series is a collection of readings rather than a measurement. Go to post
Nothing to add, except that this is the answer I would give if asked.
r.nakamura, post #5: Weighing daily and reporting weekly is a better protocol than weighing weekly, because it separates the measurement frequency from the reporting frequency. The short version is the first sentence; the rest is why. Go to post
Seasonal patterns: some people report weight loss is slower in winter than summer. Body composition and activity changes might contribute. Noting the season is useful context.
Genuinely open to being wrong about this one.
Post #89 describes the usual case. This is about the unusual one.
A note on how 40-week log gets discussed rather than on 40-week log itself: the confident posts get the replies and the careful ones get ignored, and the careful ones have been right more often.
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