Question about Scales and Calorie deficit

[Nicoledeex]

I have been at the gym for 3 weeks. I work within the caring industry so active job and also cycle to work although only 15 mins all in there and back. My calorie allowance is always showing as roughly 2500 for the day on fitbit, when at the gym it shows as 3000. 

I eat 2000 calories per day sometimes  as hungry so I listen to my body but trying to aim for 1500. The 2nd week I stood on my scales I was 10stone, but I eventually went back up to 10.2 and 10.3. Im trying to get down to 9stone but it seems the fitbit calorie count is wrong as I should have lost nearly 4lbs over the 3 weeks and this hasn't happened? 

Moderator edit: subject for clarity

[Glenda]

Multiply your weight by 10 and that is about the number of calories that will maintain your weight.  to lose weight subtract  250 or 500 calories a day depending on how big you are.   Studies tend to show that exercise is only for better health and will not help you lose weight..  If you subtract 500 calories a day you will lose 1 pound a week.    Unless you weigh 200 pounds you shouldn't be eating 2000 calories a day.   Eat better food, more nutritions with fewer calories.

[Heybales]

And I'll disagree with that recommendation because you ARE accounting for what you eat - good job. And accounting for the daily burn, hence buying the Fitbit, right.

Therefore what you burn in TOTAL for the day does matter - whether from increased daily activity or exercise - all takes calories away from the base functions of life your body needs.

And when body feels threatened - it stresses out. Cortisol increases. Retained water increases slowly, upwards of 20 lbs.

Therefore the scale doesn't always tell the whole story. Measuring several spots will help there.

Though if body is stressed like that - it'll start adapting and that will cause problems, least among them losing fat as easily as it could be. And losing muscle mass is easier when stressed like that.

With so little to lose - 500 cal deficit is decent for now, when closer you'll want 250 cal - and then accuracy really matters. 

But that means 500 off what you burn in total - and depending on how your stuff is logged you may be burning that much or more.

Your daily burn is based on distance walked, so stride length. You probably get lots of steps so inaccuracy there could throw that figure off.

Exercise is by HR calculation if starting a workout - and that could be good or bad one because HR is not a calorie burn reading, it's an estimate.

Do you start your rides as a workout, or just go? 

If just going, that means it's looking for steps and usually get very few and not correct calorie calculation anyway - so underestimated possible a decent amount.

If workout is started then by HR, but if it's an easy ride like walking easy - inflated calorie burn.

What are the 3 x weekly gym workouts, how long, do you start a workout?

The other side of the equation is food logging - again an estimate, but best estimate?

Do you log all food eaten by weight, confirming the label in hand matches the database entry?

So 2 possible directions:

1 - You've made a bigger than desired deficit and stressed body out - I don't see this as likely with only 3 weeks of time, and even then should have 1 week big loss before body is stressed. Unless your body was already stressed (disease, terrible sleep, ect) and this pushed it over the edge.

2 - You've got enough inaccuracies to almost wipe out what should be a deficit, along with some water weight gained from new gym workouts - I think this is likely.

If indeed the latter - again 2 options:

1 - Just eat less, find 500 actual calories to leave out daily. So the figures you see aren't reality but close.

2 - tighten up food logging, and correct calorie burn inaccuracies.

#2 still can't be totally accurate and you'll have to adjust anyway, but it gives a place to start from and could be useful info going forward.

But indeed don't want to cause undue stress by creating a huge deficit by not accounting for all you do.