Weight Question

September 15, 2009 2:53 PM

When is the best time of day to weight yourself for the most accurate read?

Why do I always weight several pounds more in the evening than in the morning? Also, what impacts the scale the most from day to day? What you eat/drink? Is it possible to gain three pounds overnight? I realize my scale may be faulty, but I get the same kinds of readings from the scale at the gym.

posted by dmbfan93 to health & fitness (18 comments total)

I the trick is to measure your weight at a consistent time of the day. Your weight will fluctuate throughout the day.
posted by gregr at 2:57 PM on September 15 [1 favorite has favorites]

What you eat and drink and eliminate has the biggest impact on what you weigh. It takes 3500 calories to actually gain a pound of fat, but it you weigh yourself after drinking ~20 ounces you'll weigh about a pound more than you did before.

Most people weigh themselves in the morning. If you want to be consistent you should weigh yourself every day and take a running average. This will tend to eliminate the spikes that you see due to what you put in and take out of your body.
posted by OmieWise at 2:58 PM on September 15

Thirding the above. Just weigh yourself at the same time of day, with the same amount of clothes on. When I get on the scale, I always do it first thing in the morning, after I pee, and naked. That way I'm consistent.

Also, please don't weigh yourself every single day. It just adds stress because our body weights do fluctuate based on diet, activity levels, etc. Once every couple weeks, if that, should be plenty.
posted by yawper at 2:59 PM on September 15

If your purpose is tracking relative weight from day to day, weighing yourself first thing in the morning before you've eaten or drunk anything is probably the easiest way to get an apples-to-apples comparison.

A single pint of water weighs a pound; it's easy for food and drink to make your weight sway by a couple of pounds.
posted by Zed at 3:00 PM on September 15

My doctor recommended in the morning, after going to the bathroom, before getting dressed, and doing it consistently that way. One gallon of water weighs 8+ pounds, so you can vary greatly during the day after drinking, eating, putting on different clothes.
posted by sharkfu at 3:00 PM on September 15

The best way to really figure out how much you weigh accurately is to take an average over the last 15 days. There's a Google app that does this... you just plug in your weight and it gives you your moving average as it relates to your goal, so it can tell you if you're trending up or down, no matter whether you are up or down a pound.

Most people seem to weigh themselves first thing in the morning and that's what I do. You sweat out some water weight, obviously, and there's a bunch of other factors. For me, it's

- whether I've been eating a lot of salty foods [more salt = more water retention]
- how much I've been eating generally [more food = more weight]
- time of the month
- exercise [more sweat = less weight]
- what I'm wearing [clothes are heavier than you think]

You can totally gain a few pounds overnight, but it's not real gain, it's water weight that comes and goes. Home scales are more or less accurate in a "you get what you pay for" sort of way whereas a gym scale is more likely to be more right on. If you're aiming for weight loss, weighing yourself at a regular time and just keeping a rolling average is the best way to not make yourself crazy over where that extra pound came from or went.
posted by jessamyn at 3:00 PM on September 15 [1 favorite has favorites]

Your weight fluctuates based on the amount of food and water going in and out at any given time, especially water. Your measured weight at any given time could easily be five pounds above or below your true (that is, average) weight. The best approach is to weigh yourself often and to average out the measurements. See The Hacker's Diet, especially The Rubber Bag, but also Signal and Noise.
posted by PercussivePaul at 3:01 PM on September 15

The real point of weighing yourself is to do so repeatedly over a long period of time to look for trends up and down, right?

So get up in the morning, use the bathroom, then weigh yourself before you eat breakfast. That will be consistent from day to day and best reveal real weight trends without excessive measurement noise.

Note that there will still be some noise. And a woman's weight will go up and down some over her period.
posted by Chocolate Pickle at 3:01 PM on September 15

Your body constantly has things going in and coming out, so there are several factors, but hydration level can totally make a three-pound difference, in my experience.
posted by substars at 3:03 PM on September 15

You're ~60% water. Your stored mass will fluctuate substantially due to what you drink, what you sweat, and what you excrete during the day - mostly increase, assuming you stay hydrated, during the day, and decrease at night, as you don't. If you go hard running, you'll lose anything up to several pounds in sweat.

The standard way to smooth all this in-and-out is to take a moving average of your weight, and weigh yourself at the same time. The most 'stable' time is just after you wake up and have gone to the loo, while naked; but if you forget, it's still better to weigh yourself after breakfast than not at all - the moving average will smooth that variation out too, over time.

There are two approaches to this, and which one you go for is up to you.

The first is to measure yourself every morning. Treat your weight as a number; any given weight is irrelevent, so whether you've gained or lost 3 pounds overnight doesn't matter, as it'll likely swing the other way in a day or two. Use a spreadsheet with a moving average, or do what I do and just record it on physicsdiet which is The Hacker's Diet spreadsheets in working form online. It'll do the trends for you, so you can see how you average over time. The trend is far more important than any individual data point.

The other is to weigh yourself at longer intervals; once a week or even once a month, and just plot it in a graph. Seeing your weight trend over the longer term helps escape that morning moodswing over the two pounds lost or gained overnight.
posted by ArkhanJG at 3:27 PM on September 15 [3 favorites has favorites]

The other thing I find helpful is to record my bodyfat percentage trend too, as well as my weight. You can measure it various ways; either by caliper, or by bodyfat scales such as tanita that include electrical current measuring, which is handy when you're weighing yourself naked anyway, as I find clothes throw it way off.

Either method is not particularly accurate; expect swings of several percent per day. But again, it's the trend that's important. I notice when I'm just losing water weight, my bodyfat percentage increases as my weight goes down. But when both are trending down, I'm losing real fat. It's also dead handy to spot when you're weight plateau'd, that you're actually exchanging bodyfat for muscle mass, which is nice, and helps you keep going.

It also spots when you fall off the waggon, and that mass you're putting on isn't really muscle after all...
posted by ArkhanJG at 3:38 PM on September 15

First thing in the morning is probably the best time of day, but as long as you're consistent about time of day and and other conditions, the time of day isn't particularly important. I'd also recommend sticking to one scale, even if it's not super-accurate. The point is more to look for trends.

Personally, I weigh myself an excessive amount, maybe ten times a day or so, mostly out of habit but probably also out of residual body-image issues. I don't think I'd recommend it to anyone. But! It's interesting to see how much I fluctuate throughout the day. On average, I'm about three or four pounds heavier at night than when I first wake up. Sometimes I fluctuate even more, if I've had a particularly sweaty workout or eaten a large dinner. As a result, I think of my weight as a range more than an exact number, and variations in my weight don't freak me out as much as they used to. If you want to figure out your general range, consider weighing yourself both in the morning and right before bed.

Weight is an very personal thing, and different people measure it in different ways. Some people swear by weighing themselves daily, others insist that you should step on the scale no more than once a week. Both are right, depending on the person. Whatever works for you is the way you should do it - whatever allows you to track your progress (if you want to make progress) without getting obsessive.
posted by Metroid Baby at 3:49 PM on September 15

Do it twice a day in the morning and around dinner time every day, and you'll figure out what your real weight is after a while. I disagree with those that say not to do this. It's very motivating.
posted by xammerboy at 4:08 PM on September 15

I also weigh in the morning, after I have visited the bathroom, and before I've dressed or consumed any type of food or beverage. I know it goes against conventional wisdom, but personally, I find it very helpful and interesting to weigh every day (and occasionally at night), but I know not to take those numbers too seriously. I do Weight Watchers online, so while I technically track my weight every day, I only officially weigh in once a week, and that's what I consider my true weight. Consistency is key-same time and same clothes (or lack thereof) will give you a fairly accurate idea of your weight.
posted by katemcd at 5:17 PM on September 15

I weigh myself in the morning with similar technique to yawper.

I choose to weigh myself every morning. I track the numbers in a spreadsheet and apply a three and five day moving average to the values to create some smoothing. The weight bounces around like crazy, I've had one-day swings of almost two pounds.

I also plot out the weights on a graph, and tell Numbers (I'm on a Mac and using iWork) to draw a best-fit line for my readings. The trend is downward, which is what I'm looking for :)

I'm tempted to start tracking body fat percentage too, as I have a scale to do it, but I'm a bit lazy for that.
posted by lowlife at 6:58 PM on September 15

Mornings.
posted by edmo at 1:41 AM on September 16

I'm an obsessive weigher. I weigh myself in the morning between peeing and eating, but I also check after work, after a nap, and before I go to bed. The lowest value is entered into Physics Diet.
posted by spamguy at 7:30 AM on September 16

I agree with everyone that weighing in the morning between going to the bathroom and breakfast is best. I find this the most "reliable" time of the date to get a weighing.

I do weigh daily and although there are some fluctuations, I do find that doing so helps keeping my weight under control. Most of the time, when I eat "badly", this has a direct effect on my weight the next day as I retain more fluid, when I eat more carefully and healthily, I tend to loose some weight. I know that this is not scientific and that there are other "natural" fluctuations, but in my case it does seem to apply most of the time and it can be very motivating to eat better and loose weight in the long run.

As others said, the true measure is the rolling average. I use an iphone / ipod touch app for logging my weight that called is "weightbot" which makes it easy and fun to log your weight and then graph it with rolling averages on a weekly, monthly and yearly basis. It also allows you to track progress against your goal.
posted by eurandom at 5:26 AM on September 17