Food Plan … Still Confused

[TubieGirl]

I am a 53 yo female, 5’3” and 168lbs (overweight). I’ve looked at the food plan and want to lose 1lb a week. Without exercise (possible as I have a number of chronic health conditions) I get a calorie allowance of 840 calories. Feeling that this was a bit low, I did some research.

I read all the help articles and the very informative article by @SebringDon, https://community.fitbit.com/t5/Fitbit-com-Dashboard/Fitbit-s-Food-Plan-Demystified/m-p/1155201#U115...

Following Don’s article, I established that my basal metabolic rate (the total number of calories that my body needs to perform basic, life-sustaining functions) requires 1340 k/cal a day and 1598 k/cals a day to maintain my weight based on my sedentary lifestyle. I understand that I need a 500 calorie deficit to lose 1lb a week so why is my calorie allowance not 1098? I know I can cheat the system, set a 0.5lb weight loss to give me an extra 250 calories but I really want to understand the calculation.

Any useful insight would be great.

TIA 😊

[garyanoe]

Good Morning

I am very confused about how Fitbit is displaying my Food plan. Can someone please explain what the plates represent and the bar charts below? according to another tile I use, I usually stay either under or in the zone..

[Krinerh2401]

My sister has an Iphone, and was able to choose a set amount of calories as a goal for a day, but my phone which is an android does not give that option. I had to go online on my laptop to choose what I wanted. 

[wtksk8r]

How long have you been wearing your Fitbit? It seems to me that you might not have been wearing one for long. I believe the calculation starts by using your BMR and then adjusts for it during the day depending on how much you expend with exercise. After some time it looks at your average daily expenditure and you should see a shift to a more reasonable number. 

[Glenda]

@TubieGirl  I think your calculations are fine, maybe a bit low.  At looseit.com they say multiply your weight by 10 for the number to eat for maintenance with a few minor adjustments  for height and activity.  And it isn't cheating if you want to lose 1/2 pound a week    Losing anything or staying the same is better than gaining anyway.  Doing it a way that you can stick with is very smart.  I gave you a vote but it didn't stick.  I'll try again.  Good for you for a good attitude and for getting set to try sensibly.  .  

[TubieGirl]

Thanks Glenda. This makes sense.

The cheating bit is getting the FitBit app to do what I want, not the diet 😊

[Heybales · Accepted solution]

Fitbit's initial estimate of your daily burn when set to it's Sedentary (or if set to Historical and you have none) is just a tad over it's calculated BMR (using similar to Mifflin BMR formula), may still be the 1.08 x BMR it was years ago.

Since that is the initial estimate of daily burn, your initial estimate of eating goal is that minus 500, so 840 if stats were right. If this was first day using device, forget the numbers.

Your other site was starting with a different BMR value, probably the inflated Harris BMR from a 1919 study much outdated by now.

That Sedentary value was 1.2 x BMR came from the same tired old study that has been improved on by now.

Hence the difference in your values not matching.

Now, the intent of Fitbit lowballing it from the start, is it assumes you'll be more active than that, your daily burn will go up - your eating goal will go up.

But if you are truly sedentary - it won't by much.

Fitbit assumes all non-step time is BMR rate of burn. That is true for the time you sleep, and about right sitting around doing nothing. So if you really can't get many steps in, you'll actually get a decrease of daily burn and eating goal as day goes on, as it assumes no steps, sleeping rate of burn.

You could easily end up at BMR for daily burn - and that isn't correct if awake.

But - this does point out a problem with goals - you don't really have the room in your daily calories for 1 lb weekly anyway it sounds like.

You could go a tad below BMR, but make it stressful for your body, and it's easy to lose muscle mass sadly. Really don't want that. really don't.

I'd set the daily goal to 250.

If you happen to be more active for some reason and daily burn has your eating goal above 1200, allow yourself to go that low to 1200.

That is considered minimum safe low for average sedentary female in order to get nutrition in. And your height is close to average, though your activity sounds like it may less than sedentary.

Anyway, that's one way to use the system as intended, and tweak it on the days where you have room to, and not stress your body out.

[TubieGirl]

Hi @Heybales 

Thanks for your really informative reply. The BMR I quoted was calculated using the Mifflin-St Jeor formula. Your explanation however, makes absolute sense and it sounds like a combination of the lack of actual historical data and a minimal increment to my BMR for a sedentary lifestyle used in Fitbit’s calculation.

Time will tell 🙂