Fitbit Charge HR 12 Weeks Weight Loss Test (March 30th - June 21st)

[AtomHF]

Hi Everyone, 

New Fitbit Charge HR user here! I'm very impressed with my Fitbit so far. It tracks my sleep very accurately and besides some hiccups during HIIT training sessions, exercise heart rate tracking is very acceptable (if your goal is to track calories and not zone training). 

I'm a numbers guy, so decided to test the accuracy of the calculations with real life experience during the next 12 weeks (starting March 30th). I will track my weight with Withings scale, track my food with electronic scale and if I cannot weigh/measure the food that I'm eating, I will make conservative assumptions. 

I will use a -1000 calorie program with a starting assumption that fitbit is overestimating my exercise calories (low metabolism, body type, etc). If this is not the case, over time, I will lower the deficit to -750 and then -500 based on the outcome. 

Every few days, I will post my numbers along with a line graph showing what it should be based on the calculations and what it is in my weigh-ins. 

Please let me know if anyone has any suggestions/recommendations to improve the test.

Thanks!

[AtomHF]

So it begins today 🙂    Once I have multiple data points, I will start the line charts

Starting Date: March 30th

Height: 5'8"

Starting Weight:172.6

Lean Mass: 130.5

Starting Fat: 24.4%

BMI: 26.2

[AtomHF]

April1st - 2 days 

Weight:169.5

Lean Mass: 126.6

Fat: 25.3% 

BMI:25.7 

You will see the sudden drop in weight, drop in lean mass and increase in fat%. This is due to water fluctuation in my body.Numbers should start looking more stable once I'm 2-3 weeks in to the program.

Real Weight: Weight measured by the scale

Expected Weight: Weight that I should be per Fitbit's calorie deficit 

Lean Mass: Total Weight minus Fat Weight (this will help me understand water fluctuations)

[AtomHF]

April 3 - 4 days

Weight: 169

Lean Mass: 127.4

Fat: 24.6% 

BMI:25.7 

The sudden drop is most probably due to water weight loss. I'm sure this will fluctuate over time. I would expect the red line and blue line to intersect within the next 3 weeks or trend downwards in parallel.  

[AtomHF]

April 6 - 7 days

Weight: 169.3

Lean Mass: 130.3

Fat: 23.0% 

BMI:25.7 

It is going pretty close so far. Weight is slightly up today but the fat% showed lower, so probably water fluctuation. 

[Newbietogroup]

Hi there,
would love to do this 12 week challenge as well ...

[AtomHF]

Hello,

This is not really a challenge but more of a test of what Fitbit tells you in terms of weight loss progression (based on the deficit you make) vs. how your weight really changes. There is obviously a human margin of error as you may not be able to weigh/measure everything you eat (e.g. I was at a party last night and wasn't able to measure anything, so had to estimate). At the end of the day, with -1000 daily deficit, real weight should follow a downward trend with a level of variation around the expected weight trend line. If it is not, you are either not estimating what you eat correctly and/or Fitbit is not accurate. I'm hoping to see this at the end of the 12 weeks. 

If you would like to do a similar test, please feel free to track your progress and post here or you can use this as a challenge and see how much weight you can lose in 12 weeks 🙂 

Please let me know if you have any questions

[AtomHF]

April 9 - 10 days

Weight:168.9

Lean Mass: 127.5

Fat: 25.3% 

BMI:25.7 

Going as expected so far. I had to reduce my 1000 deficit for a couple of days as I exceeded my calories. You can see the slight bend on the expected weight graph.

[AtomHF]

A quick udpate on my ongoing test:

As you will see from the graph below, my weight went up (even though I'm following a deficit, see expected weight line):

I'm not suprised by this as the weight fill fluctuate over time. I think the reason of the weight increase is water weight. As you will see from the lean weight and fat weight trend lines, my weight increase corresponds an increase in lean weight and decrease in fat weight. This tells me that the weight loss is continuing to progress (as Fitbit tells me it should)