Question about suggested calories

[TrittGirl]

Hi everyone, I have a question about the calories my FitBit says I can eat on any given day. When I put in my weight loss goal, I selected the harder plan to get to my goal (2 pounds per week). Before getting the FitBit I read that to lose 2 pounds per week you need to have a calories deficit of 7,000 calories per week. Are the calories allowed (per FitBit) the calories allowed after building that deficit in to my week's worth of calories? I've been leaving "calories on the table" so to speak (under target) but I have been losing. I just want to 1) make sure I understand how Fit Bit figures the calories & 2) I also want to make sure I'm not starving my body and doing something that will eventually slow weight loss down. 

[Baltoscott]

Hi @TrittGirl - that’s a good question.  Yes, Fitbit is trying to project a 7000 kcal/week deficit if your plan goal is to lose two pounds per week.  The obvious moving variables are how many calories you consume (making sure they all get correctly identified and recorded) and how much activity you engage in over the week.  They confounding factors are accuracy concerning calories in and out and whether your personal metabolism is close to the ‘average’ person of your age, size, sex, and weight that is used to predict the loss.

In practice, I think the best approach is to start out with Fitbit’s estimates for how much you should eat and then test the formula by weighing in.  A lot of people of afraid of the scale, but if you make a habit of weighing in every morning and recording it to your Fitbit account, it will create a weekly average that you can use to measure your progress.  A little more sophisticated tool would be something recording you weight into a program like TrendWeight (it is free, see link in my signature), or “Happy Scale” (an iPhone app).  Once you start regularly measuring your progress you can make adjustments to how much you eat to fine tune the formula.

One last suggestion.  Although Fitbit will give you ‘permission’ to eat more on big exercise days, if your goal is to lose weight you should aim to eat a similar amount of calories each day.  This requires you to do a little math.  Look at the total number of calories Fitbit says you burned last week and divide by 7 to figure out your daily average.  Aim to eat 1000/day less than that amount daily to get to your 7000 calorie deficit for the week.  If you usually eat more on some days (Hey, weekends happen!), follow that up by eating a bit less on subsequent days.

Good luck with your goals.  Let us know how it is going, and jump into the forums and let others know what has worked for you when they raise questions.