can the scale really go up 12 pounds in day?

I used to weigh myself everyday and got so annoyed with this happening to me. It's crazy how much it can change in a day, due to water intake, food, water retention blah blah blah. Try replacing the batteries if you have a digital scale- that can be a problem too.

I was wondering the same about reliability of cheap digital scales. I started logging on MFP again on Wednesday and Tuesday night was 135.5 Kg. Been strict with myself for the past 3 or 4 days and this morning I am 131.2, seems too good to be true! I did 3 weighs this morning and took the heaviest, they came in at 130.7, 131.2 & 131...

Honestly.. Weigh yourself once a week and leave it at that. If you weigh yourself after you ate, of course its going to go up because there is undigested food in your stomach.. which is why you need to weigh yourself in the morning after you went to the bathroom.

Also, if you had a hard workout, your muscles hang on to water to repair themselves... so sometimes that plays into it.

Third factor is TOM... he can creep up on you and make you gain between 3-5 pounds for no reason.. which sucks, but it generally goes away in a few days.

The good thing is that it is impossible to gain that much fat over night....so it has to be water weight or your scale.

My scales fluctuate drastically if my battery is starting to get old. Did you try changing the batteries? (if it's digital I guess lol)

i asked the same question when mine went up 7 in one day earlier this week...but it wasn't my scale

Great news, it's back down 9 today...stupid scales. i weigh myself every day, but i look at the weights each friday to see what my weekly change really is.

Do you track your sodium and water? If you've been eating high sodium, your body will retain water. Some people's bodies hold onto more than others. Also, try to weigh yourself at the same time every day, preferably in the morning. When you weigh in later, you are also weighing all of the food and water that is sitting in your tummy!

The scale can do whatever it wants, it's a piece of machinery; you, however, cannot go up 12lbs in a day in any significant way that will hurt your progress unless you let it make you give up.

If weighing everyday freaks you out when there are fluctuations, stop.
If the scale is the ONLY method by which you're gauging your progress, stop.

You will drive yourself nuts just relying on the scale to determine how you feel about what you're doing. Measure yourself, use your clothes as the most accurate judge, and give yourself a little leeway for daily fluctuations that we all have. If you're going to measure daily, make sure it is at the same time each day. In the morning after using the bathroom is the best time for me because there are fewer other factors to think about, such as quantity of food consumed that day.

Maybe, but it's definitely NOT possible to gain 12 pounds of fat in one day

Scales measure weight, not fat. It is possible to 'look' like you are 12 lb heavier.
Picture a scenario...
1/ Wake
2/ Toilet
3/ Weigh ... 180lb
4/ 8 cups water = 4.5lb
5/ A day's food = 3lb
6/ Get on the scales after a long day = 192lb (as they may be dodgy and out by several lb as mine go up and down, even when standing or moving around on it) - or worse, different scales
7/ Only going to the toilet AFTER the second weigh in - too nervous to 'let go' until after the weigh-in.
Not your scenario, but possible. Wearing the same clothes ? No ? Make up ? Cell growth ? Hair bands ? Jewelry ? Shoes ?
I do unofficial weigh once a week, and official (at the Doctor) once per month ... downward trend (some months slower than others) = good thing !

Longer term appearance of a gain ... dodgy scales, different clothing, hair longer, cell re-growth, muscular growth, fluid retention, allergic reactions, etc.

A little perspective.