Trendweight Users: Does this make sense?
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T1DCarnivoreRunner
Posts: 11,502 Member
Looking for Trendweight Users to shed some light on my recent results. Generally, I find this to be a helpful tool for smoothing out inconsistencies. However, the past 2 months have not seemed to be very accurate when comparing to the scale. Especially the last 3 weeks, as I weigh almost every day.
What I would expect: Some actual scale readings are higher than the trended weight and some actual scale readings are lower than the trended weight.
What is really happening: The Trendweight weight has been consistently higher than the actual scale reading. The last time actual weight was higher than trended weight was on 4/6.
Is Trendweight wrong? Why does it always show higher and never (at least for 3 weeks now, and as an unusual situation) lower than the scale?
Here is the 3 month trendweight chart:
https://trendweight.com/u/9a024ed6a7a149/chart/3m.png
What I would expect: Some actual scale readings are higher than the trended weight and some actual scale readings are lower than the trended weight.
What is really happening: The Trendweight weight has been consistently higher than the actual scale reading. The last time actual weight was higher than trended weight was on 4/6.
Is Trendweight wrong? Why does it always show higher and never (at least for 3 weeks now, and as an unusual situation) lower than the scale?
Here is the 3 month trendweight chart:
https://trendweight.com/u/9a024ed6a7a149/chart/3m.png
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Replies
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Mine does the same thing, In the last 3 months I think i have 3 points that were above the trend line. I was told that was what to expect.
Another poster gave me this link, that has the formula used.
http://capmblade1.blogspot.ca/2007/12/hackers-diet-examining-trend-line.html0 -
In the entire time I've been using Trendweight, I've only had my actual and trend weights be the same a few times; my trend is always higher than my scale reading when losing weight. The only time my trend was lower than my actual weight on a consistent basis was when I was bulking.2
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I don't use trendweight, but essentially that is a trendline on a scatter plot. The line shows a general pattern or direction that the data is moving (not hitting exact data points). In excel this is a trendline on a scatterplot of random data (you could use excel to do the same thing trendweight is doing).
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My trend is almost always higher than my actual weight. Though I do have days here and there where it does happen, generally around times when I have larger meals and don't lose as much weight as I should have based on my trend. (https://trendweight.com/u/4fef909d94e54b/chart/3m.png)0
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Trendweight is a weighted moving average, not a best fit line. Basically, take the last 20 measurements, weight them, and average them. If you are losing weight (trending down), then the previous 20 measurements are higher than the current measurement. Therefore I would expect the current measurement to be lower than the trend weight.2
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Your weight is below the "expected" weight each day because you are losing weight (your weight is lower than that app is predicting it to be). At the beginning, your weight entries were higher than the expected value because you were gaining.
I use "happy scale," though, and I do have some entries over and some entries under the expected value. It seems to have more daily variation in my graph.0 -
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That all makes sense... it looks like I just misunderstood what Trendweight does. I had thought Trendweight was predicting current weight as of today (which it does, but I posted a link to the graph rather than a screenshot with that detail because I am having errors uploading the image here).
So when Trendweight says your actual weight today is X, it is going to be an average of prior weights and not quite your current weight, unless you are eating at maintenance. That makes more sense, but then makes Trendweight useless because it doesn't actually give me what I'm looking for (current weight after water weight fluctuation adjustments).0 -
Yes, it is getting the prediction from previous weights. I noticed that it takes my app about 3 days of a lower weight to decide that I've lost weight. It evens out the daily bumps. That way, if you have an abnormally high weigh-in (or more than one), you'll know whether your actually gaining or it's just a bump on the graph.0
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midwesterner85 wrote: »That all makes sense... it looks like I just misunderstood what Trendweight does. I had thought Trendweight was predicting current weight as of today (which it does, but I posted a link to the graph rather than a screenshot with that detail because I am having errors uploading the image here).
So when Trendweight says your actual weight today is X, it is going to be an average of prior weights and not quite your current weight, unless you are eating at maintenance. That makes more sense, but then makes Trendweight useless because it doesn't actually give me what I'm looking for (current weight after water weight fluctuation adjustments).
A program that gives you your current weight after water weight fluctuation adjustments is basically improbable as water weight is not constant; it varies day to day based on a multitude of factors.0 -
Yes, it is getting the prediction from previous weights. I noticed that it takes my app about 3 days of a lower weight to decide that I've lost weight. It evens out the daily bumps. That way, if you have an abnormally high weigh-in (or more than one), you'll know whether your actually gaining or it's just a bump on the graph.
It looks like Happy Scale keeps more up to date, though perhaps that is because your weight isn't changing as fast as mine. Trendweight seems to be 7-10 days behind scale readings and your graph is more like 4-7 days behind scale readings.0 -
midwesterner85 wrote: »That all makes sense... it looks like I just misunderstood what Trendweight does. I had thought Trendweight was predicting current weight as of today (which it does, but I posted a link to the graph rather than a screenshot with that detail because I am having errors uploading the image here).
So when Trendweight says your actual weight today is X, it is going to be an average of prior weights and not quite your current weight, unless you are eating at maintenance. That makes more sense, but then makes Trendweight useless because it doesn't actually give me what I'm looking for (current weight after water weight fluctuation adjustments).
A program that gives you your current weight after water weight fluctuation adjustments is basically improbable as water weight is not constant; it varies day to day based on a multitude of factors.
I know it varies, but I thought part of the point of weighing daily (I miss some) and using Trendweight is to smooth out those fluctuations to show a realistic weight. In that case, I would expect some scale readings to be higher than Trendweight and other scale readings to be lower than Trendweight, depending on whether I was water-heavy or not that day. It seems I completely misunderstood the point of Trendweight - it seems like it does that, but as of 7-10 days ago instead of today.1 -
Right - Trendweight is to show you a reliable trend as opposed to accurate current weight. It's more to reassure yourself that your weight is headed in the direction you want and at roughly the rate you want.2
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Right - Trendweight is to show you a reliable trend as opposed to accurate current weight. It's more to reassure yourself that your weight is headed in the direction you want and at roughly the rate you want.
I also look at it this way: I dropped 3lbs over night yesterday, and another 2 last night. It's probably water. My trendweight weight is 6lbs heavier than my current weight this morning on my scale and I think that's a good thing because what if it is water and tomorrow I'm back to maybe 260 versus the 255 I was this morning? I will see on the trend that I'm actually still moving down because the one day super low weight didn't change my average by much. Or that one day of water weight gain doesn't change my trendweight average.
I think the average is very nice for all these fluctuations. Maybe I did lose 5lbs of fat this week but likely not, so I like that my TW weight is 260 because maybe I do actually weigh 260 and I just lost 5lbs of water.1 -
nordlead2005 wrote: »Trendweight is a weighted moving average, not a best fit line. Basically, take the last 20 measurements, weight them, and average them. If you are losing weight (trending down), then the previous 20 measurements are higher than the current measurement. Therefore I would expect the current measurement to be lower than the trend weight.
This. Trendweight is taking a 20-day moving average.
If you have an android, you can use an app called Libra that will let you mess with how many days the program uses for the average or for prediction.
I am a nerd with numbers and do all this manually in an excel file. Here's a comparison of what a 5 day average looks like compared to a 20 day average. You can see the 20 day will show my weight generally trending down, then plateauing, then trending down again. The 5 day is up and down a lot like my daily weights are. What's my "accurate" weight? Who knows. I prefer using the 20 day average as my MFP reported weight. Yes it lags my day to day scale weight. But that's better than feeling like I "gained" weight just because the scale bumps up and down all the time.
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midwesterner85 wrote: »That all makes sense... it looks like I just misunderstood what Trendweight does. I had thought Trendweight was predicting current weight as of today (which it does, but I posted a link to the graph rather than a screenshot with that detail because I am having errors uploading the image here).
So when Trendweight says your actual weight today is X, it is going to be an average of prior weights and not quite your current weight, unless you are eating at maintenance. That makes more sense, but then makes Trendweight useless because it doesn't actually give me what I'm looking for (current weight after water weight fluctuation adjustments).
No, I think Trendweight is doing something closer to what you'd want - it's showing you that you're on a downward trend. It's not so much predicting an exact daily weight, it's showing your the direction your weight is moving, and how quickly it's moving there (via how steep the trend "hill" is). But because of weight fluctuations, and the fact that it can really only look backward (it's not magic), it will not necessarily predict your exact weight .
This is not *strictly* accurate, but you can almost imagine that your individual weight dots for each day are either little helium balloons pulling up the trend line (if they're above it), or little iron balls pulling down on the trend line (when they're below it). You may have the occasional "pulling up" day, but in order for the overall trend to be downward, more of your recent daily weights need to be below the line.
Take a look at @blues4miles' excellent chart, and think about why the 5-day average line is bumpier than the 20 day average line. See how the dots are closer to the 5-day line, pulling it up and down in a kind of volatile way, but the 20-day line is smoother, so it takes more consistent below-the-line daily weights to influence its direction if things had previously been above the line.
Trendweight is showing you the direction/trend you're on, smoothing out bumps that are more probably random water weight or food/drink weight still in your digestive system somewhere.1 -
midwesterner85 wrote: »That all makes sense... it looks like I just misunderstood what Trendweight does. I had thought Trendweight was predicting current weight as of today (which it does, but I posted a link to the graph rather than a screenshot with that detail because I am having errors uploading the image here).
So when Trendweight says your actual weight today is X, it is going to be an average of prior weights and not quite your current weight, unless you are eating at maintenance. That makes more sense, but then makes Trendweight useless because it doesn't actually give me what I'm looking for (current weight after water weight fluctuation adjustments).
No, I think Trendweight is doing something closer to what you'd want - it's showing you that you're on a downward trend. It's not so much predicting an exact daily weight, it's showing your the direction your weight is moving, and how quickly it's moving there (via how steep the trend "hill" is). But because of weight fluctuations, and the fact that it can really only look backward (it's not magic), it will not necessarily predict your exact weight .
This is not *strictly* accurate, but you can almost imagine that your individual weight dots for each day are either little helium balloons pulling up the trend line (if they're above it), or little iron balls pulling down on the trend line (when they're below it). You may have the occasional "pulling up" day, but in order for the overall trend to be downward, more of your recent daily weights need to be below the line.
Take a look at @blues4miles' excellent chart, and think about why the 5-day average line is bumpier than the 20 day average line. See how the dots are closer to the 5-day line, pulling it up and down in a kind of volatile way, but the 20-day line is smoother, so it takes more consistent below-the-line daily weights to influence its direction if things had previously been above the line.
Trendweight is showing you the direction/trend you're on, smoothing out bumps that are more probably random water weight or food/drink weight still in your digestive system somewhere.
No, Trendweight is not doing what I want. I was expecting it to determine, based on trend and scale readings, a "true" weight irresepective of water fluctuations. I was under the misunderstanding that it took prior scale readings, smoothed them, and predicted current weight based on trend. It sounds like what it really does is just create a rolling average of historical results... something quite simpler than I thought, and not forward-looking in the slightest.
I understand it now, though a bit bummed it doesn't work for me. Thank you for all those who clarified how it works. If someone knows of a tool that does what I'm looking for, please let me know. Otherwise, I might consider creating my own in Excel.0 -
midwesterner85 wrote: »midwesterner85 wrote: »That all makes sense... it looks like I just misunderstood what Trendweight does. I had thought Trendweight was predicting current weight as of today (which it does, but I posted a link to the graph rather than a screenshot with that detail because I am having errors uploading the image here).
So when Trendweight says your actual weight today is X, it is going to be an average of prior weights and not quite your current weight, unless you are eating at maintenance. That makes more sense, but then makes Trendweight useless because it doesn't actually give me what I'm looking for (current weight after water weight fluctuation adjustments).
No, I think Trendweight is doing something closer to what you'd want - it's showing you that you're on a downward trend. It's not so much predicting an exact daily weight, it's showing your the direction your weight is moving, and how quickly it's moving there (via how steep the trend "hill" is). But because of weight fluctuations, and the fact that it can really only look backward (it's not magic), it will not necessarily predict your exact weight .
This is not *strictly* accurate, but you can almost imagine that your individual weight dots for each day are either little helium balloons pulling up the trend line (if they're above it), or little iron balls pulling down on the trend line (when they're below it). You may have the occasional "pulling up" day, but in order for the overall trend to be downward, more of your recent daily weights need to be below the line.
Take a look at @blues4miles' excellent chart, and think about why the 5-day average line is bumpier than the 20 day average line. See how the dots are closer to the 5-day line, pulling it up and down in a kind of volatile way, but the 20-day line is smoother, so it takes more consistent below-the-line daily weights to influence its direction if things had previously been above the line.
Trendweight is showing you the direction/trend you're on, smoothing out bumps that are more probably random water weight or food/drink weight still in your digestive system somewhere.
No, Trendweight is not doing what I want. I was expecting it to determine, based on trend and scale readings, a "true" weight irresepective of water fluctuations. I was under the misunderstanding that it took prior scale readings, smoothed them, and predicted current weight based on trend. It sounds like what it really does is just create a rolling average of historical results... something quite simpler than I thought, and not forward-looking in the slightest.
I understand it now, though a bit bummed it doesn't work for me. Thank you for all those who clarified how it works. If someone knows of a tool that does what I'm looking for, please let me know. Otherwise, I might consider creating my own in Excel.
Not sure what you would think the difference is between smoothing something or taking the average. And as far as taking average of historical results, not sure what other data you could use. As I mentioned above, Libra works similarly to Trendweight but will let you choose the number of days to average. It sounds like the 20 day thing is your biggest problem, it's too long/slow a trend for you. A 3 day average would be more volatile than 20 day but closer to reflecting the last several days on the scale. As an excel nerd of course I don't mean to dissuade you from that, but something like Libra might be easier.
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It is a true weight, irrespective of water fluctuations, it's just lagging by a few days. That's the nature of using a running average. An excel spreadsheet can't predict either. If it's really important to you to know what you weigh THIS EXACT MINUTE then you can take your average weight loss and extrapolate from the start of the month. It's looks like you're losing 5 lbs a month, or about .17 lbs/day, that's your prediction. Whatever you're doing, it's working. Keep it up.1
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I'll take a look at Libra, thanks @blues4miles .
It isn't a matter of knowing whether I'm gaining or losing, it is trying to come up with a fair current weight irrespective of fluctuations. I've always understood that Trendweight smooths out volatility, and misunderstood that it also results in a more accurate current weight.0
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