Confused about calorie allowance

[SunsetRunner]

just bought a fitbit blaze and set up a food plan with a 750 cal deficit but its now telling me my goal is to eat 1058 calories a day which is very low for 5'8 male 140lbs. synced it up to myfitnesspal which i had a calorie allowance of 1750 cals a day set both of them to lose 1.5lb a week so dont understand why it would be such a big difference between two apps. thanks for any help

[JohnRi · Accepted solution]

First of all a 750 calorie deficit is huge deficit for someone who weighs 140 lbs.  Your bmi is 21, which toward the bottom of the BMI weight range.  18.5-19 is the bottom of the healthy range.

Your BMR is around 1600-1650.  As a male you should never eat less than 1800 calories.  If you really want to lose weight you should eat a healthy diet around 1800, and just exercise a lot so that your burn around 2250-2500 calories a day.

Another reason such a high deficit is a BAD idea, when you weight as little as you do, and you try a high deficit diet you body tends to burn muscle, and hold onto the fat.  So you you don't want a deficit of 500 or higher.  250 is about the only deficity, with is only half a pound a week.  Any more than that, all you will lose is muscle.

What exactly are trying to achieve? 

The reason why your fitbit is giving you low number is your food plan is probably set to sedentitary instead of personalized.  When set to sedentitary, you have to earn your calories to eat.  Which why the number is so low. 

The fitbit app and myfitnesspal do not care if you entering a bad calorie deficit, or that it's even dangerous.  They just look at hard numbers.

Do you know your fat %?  What is your goal?  And why?

[emili]

So yes it is set up to earn calories based on your activity level for the day. You will notice your allowance increase as you move. I guess I too am wondering why you would want to lose weight. I think you are already very slim, anything more on a man I don't think would look attractive- my opinion of course. I also am not sure about additional health benefits. Are you doing it for a weight class in a sport? And truly you don't have to answer any of the questions. It is completely your business- you just peaked my curiosity.

[SunsetRunner]

My bf is around 15% but wanted to drop off the excess few pounds to get leaner but will change my deficit to 250 as you say. Thanks