In the process of navigating the world of fitness, I’ve heard lots of arguments about the scale. The most common of these take the form of scale rejection, as in: “Weight is just a number, and it doesn’t define me” or “I don’t care about weight. I care how my clothes fit/how I feel.” In some ways, these arguments ring true. Yet weight still has a place in fitness regardless of one’s goals. I want to to try to unpack these arguments — and others like them — to see how they fit into an overall fitness routine and to try to answer the question: “Should we weigh ourselves? And if so, how often?”

It’s probably easiest to start with a quick breakdown of the cons of weight as a metric, because there are quite a few.

The Dark Side of Weight

There’s a lot of truth to anti-scale arguments.

Con #1: Weight varies. A lot.

As someone who’s weighed myself almost daily for years, I can attest that my weight varies significantly from day to day, or even hour to hour. There are a lot of reasons for this. Most obviously, until you void it, all the food and drink you take in is, you know, still in you. It’s not fat or muscle (or bone). It’s just there in you, waiting to be processed and used. So if you weighed before lunch and then again after lunch, your weight would increase by the weight of the food you consumed.

Even if we consider that during the course of the day your food is processed into fat or muscle, we have to keep in mind that the process by which this happens is far too complex to allow accurate prediction of how long this takes. Sure, it’s a fair guess that a race-fuel gel will digest/convert faster than, say, a bowl of steel-cut oats, but that doesn’t do much to help us guess exactly how long it’ll take, nor does it take into account the fact that these mix in the stomach if consumed at similar times — or mix with already partially-digested food if consumed at slightly different times. Bottom line: as one’s eating schedule varies, it’s possible to gain and lose weight through the course of a day, too. For (very rough) example, if you missed your snack and lunch, but ate a big mid-afternoon snack, you might lose a tiny bit in the morning (when you’re in calorie deficit) and gain a tiny bit later (when you’re in surplus).

I’ve seen my own weight vary by up to 5 pounds during a 24-hour period, and it seems to vary about three pounds depending on at what point within a three-hour period in the morning I happen to weigh.

Con #2: Weight doesn’t directly measure health, fitness, or even appearance.

My friend (and personal trainer since the start of my journey) Mitch has related more than once that one of the worst things a person can do when setting out to make major body changes is to choose a goal that’s not one’s actual desired goal. When you think about it, this makes a whole lot of sense. The only thing more depressing than screwing up and not achieving a goal is to struggle like hell, throw yourself entirely into the process, succeed in reaching the goal, and then discover that you don’t get any satisfaction from the achievement.

There’s more than enough behind this statement to fuel an entire separate blog post, but suffice it to say here that in my opinion, being honest about real goals is a critical factor in achieving big fitness changes.

Weight, as I’ve heard many people say, is indeed “just a number.” It’s only interesting in terms of what it predicts. What I didn’t understand at the outset of my journey — but Mitch did, thankfully — is that while weight does, in very general terms, correlate to changes in what one can do and how one looks physically, it doesn’t correlate exactly.

To give just one example of this, when I started to approach my “goal weight” of ~180 lbs., I got excited. It seemed very reasonable that, having spent 5+ days a week in the gym for half a year, I would look pretty muscular when I reached that “goal.” But I didn’t.

Here’s a picture of me at 180 pounds:

I wasn’t unhappy here. But after hundreds of hours in the gym, I should look bigger, yeah?

While I was indeed 180 pounds, I looked almost small. Why? It turns out that while I weighed 180, my body was still composed of approximately 24% fat. (We’ll come back to this.)

Suffice it to say that choosing a goal by weight alone is very risky. Maybe for you, seeing a specific number on the scale will bring you all the satisfaction you need. But will seeing numbers appear on an LCD really carry you though months or years of effort?

Con #3: For many of us, weight carries a lot of emotional baggage.

I’m pretty desensitized to seeing my weight documented at this point, both because I weigh regularly and because almost everyone who sees me now, having not seen me since I was obese, wants to talk about it. But even I’ll admit to reacting badly to seeing a particular number appear on the scale. I remember one time specifically when I met with Mitch to do a weigh/measure after a particularly rough and painful week of heavy lifting and eating uncomfortably large meals. We expected a gain of approximately two pounds, about 2/3 of which we hoped to be lean body mass (i.e. muscle), but I actually gained 2.5 pounds, all fat. It was a kick in the balls. Thankfully, I got through it by just ignoring it and moving on, but it wasn’t a happy day.

Even seeing this number (about 7 lbs heavier than normal–I’m wearing clothes and carrying a phone and camera, plus I just ate) bothered me.

It can be far worse during an initial loss phase, primarily (at least in my opinion) because at that point we don’t have anything to compare against but the scale. I wasn’t athletic earlier in life, so I had no idea what it felt like to be fit; I just looked at the number. And this doesn’t take into account far worse scenarios. For example, while I have all sorts of problems in terms of “medicating” myself with food, I’m lucky to never have experienced the full-on effects of disorders such as anorexia or bulimia.

The closest I can come to describing any of this (and it’s not close to the extreme cases), is telling you how difficult it was for me to increase my food intake to gain weight. The process of reducing body fat at essentially the same weight involves cycling between gaining and losing weight, because the two processes — adding muscle and losing fat — require different nutritional states. Losing fat requires operating at an energy deficit, while gaining muscle requires operating at a surplus. So in general terms, the fastest way to make the change is to eat at a surplus (while doing the right gym routine to encourage muscle development) to gain a certain amount of weight, more of which is muscle than fat. Then you flip the process, eating at a deficit, which when accompanied by the right workouts allows you to lose a little more fat than muscle. Done correctly, when you return to the initial weight, you’ve added some muscle and lost some fat, changing your body composition toward the lean side.

That sounds well and good, right up until you put the numbers to it. Switching from a 500 calorie deficit to a 500 calorie surplus is a change of a 1,000 calories in a day. The first time I tried to eat 1,000 more calories in a day, I was absolutely convinced I’d become fat again in a week. It scared the crap out of me. Even having worked through many, many of these cycles, I still have trouble with the switch sometimes. I also have trouble adjusting for significant workouts to make sure I hang on to my hard-earned muscle and maintain weight. (I ate ~5,000 calories, for example, last Sunday, having burned over 3,000 during the century ride alone.)

Considering how damaging weight can be to our goal-setting and ego, why weigh at all?

The Light Side of Weight (Heh.)

Yes, weight is scary. And it doesn’t predict anything on its own. But it’s an incredibly useful metric. You just have to manage it correctly to offset the dark side.

Solution #1: Weigh often, and look for trends rather than individual numbers.

Let’s start with variance. While lots of folks recommend weighing only once every week or month to help average out variances (and their emotional impact), I strongly disagree. In my experience, weighing more often rather than less often is much more helpful in dealing with weight variations. Here’s why:

Envision this: during a heavy weight-loss phase you’re busting your ass (in the gym and in your mind, to manage your eating) to lose a predicted pound a week. You plan to weigh every two weeks. On your last weigh-in, you weighed 177.2. At your next weigh-in, you weigh… 178.8. This sucks! Instead of losing a pound, you actually gained about a pound and a half. You feel like you pretty much worked the whole two weeks for nothing, or, worse yet, sabotaged yourself somehow.

Let’s play God here, and pretend we can look behind the scenes. The hypothetical you doesn’t know this, but that first weigh-in happened to fall on the low side due to the fact that you were dehydrated that morning. You really weighed 178.5. The morning of your second weigh-in, you had slightly less of a bowel movement than normal (and you had a pretty high-fiber dinner the night before) so you ended up on the high side of the variance and actually weighed 176.6. In reality, you lost 1.9 pounds during those two weeks — almost exactly as predicted.

Now envision another hypothetical where during that same period you weighed every day. You can see that your weight varied a lot from day to day, but there’s a clear trend line, something like this:

Despite the highs and lows, it’s obvious to anyone looking at the graph that you’re headed in the desired direction at the desired rate. (Conversely, a “flattening” of the trend line would indicate a real problem — supported by multiple data points, thus helping to “average out” the errors.)

Guess what? I made up the God-view “reasons” for the variances in that example, but the data is real. It represents my own weight from September 28th, 2011, to March 11th, 2011, and the hypothetical “real” weights came from the above linear trend line applied to my data. If I include a wider range of data around that two-week snapshot, the trend (and variances) are even more clear:

Solution #2: Consider weight in combination with other metrics.

Even if we factor out most of the variance issues, weight alone only tells part of the tale. But when combined with other metrics, weight data becomes a valuable resource.

For example, weight plus body composition does a remarkably decent job of estimating progress toward appearance goals. I used this information to change my initial “weight” goal to a more honest appearance goal, which Mitch and I chose to operationalize through weight plus body composition goals. While I didn’t look at all like I imagined I would in the above photo at 180 pounds and 24%, here’s a photo at 175 pounds and 14%:

I’m making rice cakes for a recent long ride.

It’s interesting to note that to get from the first photo to the second, I cycled up as high as 190 pounds and as low as 162 pounds, on purpose, in order to lose the fat. I’m much happier with the second photo, even though I’m “smaller” than I am in the first. I look better (to my eye, which is the most important eye, in my opinion) and I’m far more capable, too.

If you’re considering a weight loss goal, this idea of thinking in terms of weight + composition (instead of weight alone) is worth contemplating for a moment. Switching to this way of thinking helps avoid a number of common weight loss issues, like becoming “skinny fat.” Audra coined this term a while back, and it accurately describes what happens when one prioritizes losing weight over losing fat. Such a person may be “thin,” defined as “physically small,” but retain very high body fat. Physical appearance aside, this state presents at least one serious downside: lack of lean body mass both seriously hinders one’s ability to perform athletically — and I mean this in the most wide use of the term, to include things like walking around and picking things up at home — but even worse, it also makes burning calories difficult, which can lead to re-gaining weight. (This is worth more discussion, but outside the scope of this post.)

Weight also serves as a great cross-reference for dialing in nutrition and exercise calorie estimates. Again, this is a subject worth a lot more discussion, but here’s the down-and-dirty short version:

Despite complicated details, the core of managing weight involves managing energy in vs. energy out. At the most cursory level, there’s a formula for this:

$3500Wc=Ci-Cb$

where Wc = weight change in pounds, Ci = calorie intake, and Cb = calorie burn. Or, a little algebra lets us solve for weight change like so:

$Wc = (Ci-Cb)/3500$

So, if you were to eat 14,000 calories and burn 17,500 calories in a week, we can plug those numbers in and see that you should see a change of about one pound lost. Simple.

Sadly, though, it’s damn difficult to estimate either calorie intake or calorie burn. Even if you religiously log everything you eat, the FDA rules for food labeling allow for some discrepancies. Your food scale (if you’re using one) may be slightly mis-calibrated. If you eat at restaurants, the food may not be prepared identically to the meal tested — or you may not have access to any quantitatively-determined nutritional information about the dish at all. The calorie burn side of things is even harder to estimate.

Assuming you’re working hard to guess as closely as possible, though, most of these issues result more in inaccuracies then in inconsistencies. For example, maybe you log 100 calories when you eat a specific food, but it’s really 110; and maybe you log 500 calories for your morning run when it’s really more like 400. Neither of these numbers is correct, but they do tend to fall approximately the same distance off the mark over time. Here’s where your weight data can help out.

Looking back to our example, maybe you estimated your intake over a week to be 14,000 calories and your burn to be 17,500. We plug those in (as above) and get a predicted negative one-pound change in weight. But looking at the change in your daily-weight trend line, you see more like half a pound of loss. If you saw this for more than a few weeks in a row, it’s a likely indicator that either your estimation of your burn is higher than your actual burn, or that your estimation of calorie intake is too low, probably by about 500 calories net per week.

There are ways to tell which one is off, but who really cares? You could simply try adjusting your food intake down about 500 calories a week by eating about 75 calories less a day and re-running the calculation for a few weeks. If your loss stabilizes to more like the one pound weekly loss you expected, use the numbers and move on. The numbers, at least to me, matter far less than the results.

My Conclusion

Personally, I find weight too useful a metric to justify throwing out the scale. I weigh daily, even during periods where I’m not pushing for any major changes in weight. Without those numbers, I couldn’t have diagnosed (with help from my trainer) a number of issues that pushed me off-course from my goals at the time, and I’d have wasted a lot of valuable time achieving those goals. I think the above information makes it pretty clear how useful weight data can be.

But nothing above helps deal with the emotional baggage. Leaving that baggage behind has proven to be the hardest part of the journey for me, and I’ll fully admit that it’s something I’ve never been able to entirely accomplish. Sometimes I’ll step on the scale, see a larger number, and anxiously start tying crap together in my mind, like “I did eat a little too much yesterday” and “maybe I didn’t push myself as hard as I thought I did on that run.” But I’ve made some progress, too. Most significantly, I now tie less of my self worth directly to weight.

To some extent, I have weight data to thank for this progress. It’s helped to clarify some things, like how The Rock (about 265 pounds) and Craig Alexander (about 150) are both awesome as far as I’m concerned, yet their weights run counter to standard measures like BMI. (Note that they both fall on the very low end of body fat.)

D. Johnson, left, photo c/o Twitter (@therock). C. Alexander, right, photo c/o Twitter (@crowiealexander).

Along those same lines, I’ve seen myself in the mirror for over a thousand days at different weights. Also, I’ve eaten 2,000 calories over my intended intake in a day (big oops) and witnessed that I didn’t necessarily explode out into the Michelin Man overnight. (In many cases, the ~1/2 pound of weight change was buried in the error.) I’ve seen huge daily swings fail to derail steady trends. Yet I’m just now beginning to relax my death grip on my nutritional habits, letting myself make some small mistakes while remaining generally on course.

Most importantly, I feel like hiding the scale is, for me, hiding from the problem. One of my deepest goals is to someday conquer my fears and live well.

I’m by no means recommending some kind of stupid immersion therapy by which you beat yourself all to hell with weight numbers. But if you can survive the process, they’re super useful. Surrounding yourself with good people who’ll help you through the tough times helps, especially when they’ll remind you that you’re fine when you make a small mistake — but also help you recognize when small mistakes are becoming the norm.

In the end, you’ll have to make your own decision. I’d love to hear about it.