2 pounds in two days?

[notperfect]

I sit reall possible that I gained 2.4 pounds in 2 days?  Admittedly I went astray from my diet by eating 3 slices of pizza yesterday and 2 today (But ate nothing else today except some grapes.  Could I really have gained back two of the 6 pounds it took me almost two month to lose?

[smhermione]

Not in one day.  Also think of the salt intake that you had while eating the pizza and whatnot.  That is going to cause your body to hold onto water for a few days.  As you get back to your better eating you should see that weight go back down in a couple of days.  Good luck and don't stress out when you splurge as long as you keep your eyes on your goals.  Each day is a new day, don't hold onto the past you can't change.

[Heybales]

Part of the first big weight loss was NOT fat, but water weight.

As described above, usually people watch their sodium better, so chunk there.

Another big chunk is your body just stores less carbs in the muscles, and those store with water.

So when you ate perhaps up to maintenance, perhaps over maintenance by 250-500 calories, you gained water weight with sodium and topped off carb stores.

Always remember the math for any fast gains or losses.

3500 calories per pound of fat, if indeed it was fat.

So you lose 2 lbs in 2 days, if you think it's fat, that would mean you ate - 

2 lbs x 3500 / 2 days = 3500 calories each day below what you burned.

So if you ate 1500 calories - you really think you burned 1500+3500=5000 calories each of 2 days?

And to question your 6 lbs in 2 months, knowing again some of that was water weight, so perhaps 4 lbs of fat in 2 months.

That would imply a deficit of - 

4 lb x 3500 / 60 days = 233 eating to what you burn.

Do you indeed have your goal setup for 250 calorie deficit?

Because if you have selected 2 lbs weekly, and you are indeed eating to goal - got some bad news for ya.

Either your food logging is just totally awful to wipe out over 750 calories of deficit, or

Your manually logged exercise is really badly inflated, or

Combo of both, or

You started Fitbit already in an extreme diet and you are no longer dealing with a healthy body that Fitbit is estimating correctly with, or

Combo of all 3.