Too many people look at the scale and act as though they have received a revelation from an oracle, detailing all there is know about their current level of fitness. Many see that solitary number as the one and only holistic score of fitness. As a result, I want to take some time to dispel some misconceptions about scales and body weight in general.
Don't look at the scale
First, scales are idiots. They only know one thing about you: how much the earth's gravity is pulling on you. It doesn't know how much your shoes weigh, it doesn't know how much that delicious burger sitting in your belly weighs, and most importantly, it doesn't know how FIT you are. Unless you track your weight very consistently and over a long period of time, to just step on a scale and accept that number as any indication of the shape you are in, is just silly.
To demonstrate this, I weighed myself 32 times in one day, and these are the results.
As you can see, my weight changed pretty drastically throughout this period. I was even very careful to wear the exact same thing each time, and not have my phone or anything on me to change my weight. If you want to see the reason for each of those weight changes, check out the graph below.
The scale is always wrong
The most important thing to take away from that chart is that about 28 of those 32 weights are VERY WRONG, and the other 4 are slightly wrong. If I'd only weighed myself at 7pm, I would think I weighed 176.0 lbs. If I'd only checked when I woke up, I'd think 174.6 lbs. If I'd only checked right after the gym (a common time for people to weight themselves), I'd think I weighed 172.6 lbs. I could easily make the argument that I woke up one day at 174.6 and the next day at 172.6, so clearly I lost 2 lbs that day! We will see a few paragraphs down that this is basically a physical impossibility. The only accurate way to read a scale is to say plus/minus 4 lbs (approximately). This means that when I see a scale that says 174 lbs, the correct way to read this is somewhere between 170 to 178 lbs...ish. This way, when you see the scale 2 hrs later and it says 176, you realize this means 172 to 180, which is basically the same number. Now, if I were to weigh myself in 6 months and it said 225, then yes, I probably gained 50 lbs, but differences of 1, 2, or even 5 lbs mean almost nothing.
So what is important?
Now, I want to talk about things that actually change your body weight. Most people agree on the formula 1 pound = 3,500 calories (technically kCal but whatever). But what does this really mean? I just ate a 1 pound burger that said it was 700 calories. How does that work? It is quite simple. If you weigh 170 and pick up a 5 lb weight and get on the scale, what will it say? Obviously, it will say 175 lbs. Is it then correct to say you just gained 5 lbs? NO! In just a minute, you will put that weight back down and the scale will again say 170. So this begs the question, if you eat a 2 lb lunch (1 lb burger + 1 lb of water), what will the scale say? It will say 172 lb. Does this mean you just put on 2 lbs? NO AGAIN! Sparing the details, you will be discarding this weight very soon. But will you weight 170 after? No. This is where calories come in. The burger contained 700 calories and the water contained 0 calories. 3500 calories is 1 lb so 700 calories is 0.2 lbs. After all is said and done, you will weigh 170.2 lbs. When a burger says it is 700 calories and 1 lb, it means you will instantly gain 1 lb, but you will dispose of 0.8 lbs later, retaining 0.2 lbs. Thus, you have gained 0.2 lbs. In the case of the pound of water with 0 calories, you will gain 1 lb instantly, and either sweat or urinate the entire 1 lb off (usually a combination of the two). So, in short, you consumed a 2 lb lunch and gained 0.2 lbs of weight. Now go run!
I gained 3 lbs today!
Lastly, let's consider a comment we've all heard someone say at one point or another. I gained (or lost) 2 (or more) lbs today! We will just examine the case of someone gaining 3 lbs in 1 day. Well we already know that 1 lb is 3500 calories so 3 lbs is 10,500 calories. Unless you are unconscious the entire day, it is almost impossible for an adult to burn less than 1000 calories in a day. Thus, in order to actually GAIN 3 lbs in 1 day, you would have to consume 11,500 calories (21 Big Macs) while remaining almost motionless the entire day. While you might have become 3 lbs heavier (easily accomplished by drinking 48 oz of water), you have not gained 3 lbs. Just for comparison, consider that at one point in the days leading up to Jaimie's competition, she had to drink 2 gallons of water in a day. This means she became 17 lbs heavier that day JUST FROM WATER. It obviously found its way out of her system, but there is a difference between gaining weight and becoming heavier.
MORE MATH! (you don't have to read this part)
For those of you who haven't had enough math yet, here is one of the many kinds of calculations you can now do armed with this knowledge. I went to the gym at 174.5 and returned at 172.6 lbs. Should I be excited that I "lost" almost 2 lbs!? No. I was on a treadmill with a computer that knows I burned around 500 calories which is 500/3500 or 1/7 or 0.14 lbs. The other 1.76 lbs was just water weight because I sweat like a crazy person. Knowing this, the next thing I should do is drink a pound or two (16 - 32 oz) of water to rehydrate myself (which I did). Since food doesn't weigh anywhere near as much as water, and you don't really lose much weight in day, almost all fluctuations in weight are just an indicator of your level of hydration. Use this knowledge. Stay hydrated!