"Good explanation here."

I’ve found some interesting articles on the topic of weight fluctuations throughout the day.  I know it happens to me… I’ll be 3-5 pounds heavier during the night time hours & when I wake up the next morning i’m back down 5 pounds less.  So…. why does this happen?

Scales don’t always give you the whole story about your body or your weight loss progress. For that reason, scales (when used alone) are not a good method of tracking weight loss. The problem with body weight scales is that they measure everything–fat, muscle, bones, organs and even that sip of water you just had. The scale can’t tell you what you’ve lost or gained, which is important information if you’re trying to lose weight…and by weight, what we really mean is fat.

Here are just a few things that can increase your weight, causing it to fluctuate as much as 10 lbs in one day:

Water. Because the body is about 60% water, fluctuations in your hydration levels can change the number on a scale. If you’re dehydrated or have eaten too much salt, your body may actually retain water, which can cause scale weight to creep up. Similarly, many women retain water during menstrual cycles, which is another thing that can make that number change.

Food. Weighing yourself after a meal isn’t the best idea simply because food adds weight. When you eat it, your body will add that weight as well. It doesn’t mean you’ve gained weight, it simply means that you’ve added something to your body (something that will be eliminated through digestion over the next several hours).

Muscle. Muscle is more dense than fat and it takes up less space, so adding muscle could increase your scale weight, even though you’re slimming down.

That doesn’t mean the scale is useless. In fact, it’s a good tool when you combine it with your body fat percentage. Knowing both of these numbers will tell you whether you’re losing the right kind of weight…fat. Simply multiply your weight by your body fat percentage. For example, ME , who weighs 193 lbs with a current 32.3% body fat has 31 lbs of fat and 118 lbs of lean tissue (193 x .323 = 62.33 lbs of fat, 150 - 62.33 = 130.67 lean tissue/muscle).

Keeping track of these numbers on a weekly or monthly basis (not daily) will help you see what you’re losing and/or what you’re gaining.

Here are some articles that explain it in greater detail:

Many factors can cause daily weight swings - no matter what you eat

Weight fluctuations: are you losing body fat or water?

Why the scale lies…

Inches, the TRUE measure of how our bodies are changing