Every diet book will tell you that you should try to weigh yourself under the same conditions every time so that you minimize the effect of daily fluctuations in weight (caused by eating and drinking) on the readings you get.
Virtually every diet book will also tell you that as you diet you can expect considerable ups and downs and that you shouldn’t worry about these. They are caused by various factors, most notably your body’ retaining fluids for reasons which may not be obvious. Consequently, you shouldn’t worry about these multi-day fluctuations in your weight. As long as your overall weight goes down over time, you’re making progress toward your goal. To keep you from stressing out about these upticks in what the scale tells you, some diet books will recommend that you only weigh yourself once a week. That will give you a better chance of seeing a lower reading than what you saw the last time you got on the scale, but it will not guarantee this.
From what I’ve seen in others who have followed this strategy, it may actually increase the stress they feel when they see an uptick in the scale reading. They feel like they have wasted a whole week of dieting, and if they don’t weigh themselves for another week, they’ll have that feeling hanging over them for a week.
So I don’t do that.
I tend to be systematic in my approach to things and, since I have something of a scientific bent (as illustrated by this blog), I keep detailed info on my diet, exercise, nutritional supplements, etc. By analyzing this data, I can note trends over time and figure out what my body best responds to.
One item I keep track of is a daily reading of my weight, which I used to generate the above graph (click it to enlarge it in a pop-up window). It shows me losing sixteen pounds between April 9th and May 30th. (Overall, I’ve lost almost forty-four pounds since going back on my diet in mid January, after taking a few months off to let my metabolism re-set.) The graph lets you see the kinds of ups and downs one can expect during an effective diet, which is why I thought I’d show it here. Most diet books don’t show what your weight trendline is likely to look like, but it seems to me that it would help prepare the reader for the kinds of ups and downs to be expected.
One of the things I’ve noticed over time is that I tend to have a weight rebound immediately after each time I achieve a new low (unless I’m on a semi-liquid variant of my diet that keeps pushing my weight down). It’s like at each new weight low my body decides that it needs to reassure itself that we aren’t going to starve, so it starts hanging on to water and my weight increases temporarily. You can’t see this very well on the above graph because of the special events it records (the colored areas), but now that I know this happens, I expect it and so I don’t get concerned when it happens. It’s a normal part of how weight loss works for me.
Another thing I’ve noticed is that the stress of travel will cause my weight to bounce up. That’s what’s happening in the purple box on the track line. It was the day I went up north of L.A. to give talks at a Protestant school. Sure enough, when I got back my weight had gone up (this particular spike is exaggerated due to the time of day I had to weigh myself), but the effect was temporary and only lasted a few days.
The two blue boxes on the graph represent tiems I was varying my diet. I occasionally do experiments to see if I can make it more effective than it normally is. (Normally I lose two pounds a week on average.) The first blue box represents a period when I switched to an almost-all-liquid diet that focused on protein. At the moment, I’m trying a diet variant focusing mostly on fat. I can’t maintain such diet variants for overly long (they tend to be way too BORING to sustain indefinitely), but gathering the data will show me what my body responds to best.
I use moving averages to determine if my overall weight pattern is going up or down.