Massive Drop In Weight (seemingly)

It is normal to be a couple of pounds lighter in the morning because you continue to lose water through perspiration and respiration all night and don't replace it.   Were you wearing the same clothes, same shoes, and have the same stuff in your pockets?  That can make a few pounds difference.   It is normal to fluctuate.  If you check your weight regularly, you will begin to notice the things that account for the differences.  Water weight varies a bit.  Look for the long term trends.

Here is a simple trick for averaging your weight.  Take .9 times yesterday's weight add .1 times today's reading on your scale.  Record that as today's weight.  Yesterday's weight is the averaged value obtained by the same calculation yesterday.  For the first day, just write down the scale reading.  

If you write out the summation,  it is a weighted average of .1*scale today +.09*scale yesterday +.081* scale two days ago+...+ (.1*.9^n)*scale n days ago.  The effect is to average out the fluctuations and leave a clearer trend.   

TW

Sometimes that happens to me.  If I weigh myself after dinner, I am usually at my highest weight.  First thing in the morning, I am at my lowest.   I think you need to just pick a time of day and always use that weight.  Then the comparisons are valid.  

You can store a lot of weight in your digestive system.  Water, food and waste that can effect your weight considerably.   Overnight you body processes all the additional food and water.  I think that is why you weigh so much less in the morning.    

That sounds like a good formula, but a litte complicated for me.  I just track daily weight in my training log and then use the graphs to show me average  weekly weight.  YOu can see a trend graph without any math involved.  Works great for seeing your trend of weight loss (or gain) over a few weeks or months.

phew good thing it's 6pm over here now dave lol

maybe it's your scale though... i've had a scale that would show me changes like that, then stay the same for a while and then do it again.. my other scale always showed me something different so i stuck with the old one (especially cuz i know it's pretty acurate)...

Have you changed the amount of salt you have been eating?  I've just started a new nutritional plan and part of it is cutting the amount of salt in my diet.  I have lost 5 pounds in the last week.  I'm sure most of it is due to the lower amount of salt and therefore I'm retaining less water.  I was 188 last friday and I was 183 this friday.  Granted I've also changed my food intake a ton so that could account for a little bit.

If you haven't changed your diet then I have no idea why the weight loss would be so dramatic.  Training you should see some weight loss if you are watching what you eat but  the only way that you could lose 10 pounds that quickly is if it was water IMO.  10 pounds of fat means a calorie deficeit of around around 32000 - 35000 calories and it would be impossible for your body to burn that much over night or in the period of one day, unless you are doing a few ironmans. 

Some scales aren't accurate plus they need to be reset sort of on the floor. We have tile floor in our bathroom and if it isn't centered right the scale reads off.

What kind of floor do you have? I pick up my scale and shake it and put it down and often it reads way different.

10 pounds seems very weird...mabye up to 5 for water retention differences. Do your clothes fit different? Normally 10 pounds is a size smaller in clothes for me.