Calculating macros

[rcalvert89]

I don't understand how I have eaten 36g of fat today and 69g of protein but it is saying my macros are 52% fat and 33% protein can anyone explain this. I want to start tracking this, but seems very counterintuitive... maybe something is wrong? or maybe I am thinking about it in the wrong way?

Moderator edit: format. 

[MrMarv · Accepted solution]

@rcalvert89 - 

Each gram of carbs and protein contain 4 calories while each gram of fat contains 9.

So for the sample daily totals below:

25 grams of fat is 225 calories

238 grams of carbs is 952 calories

57 grams of protein is 228 calories

The above total 1405 and my iOS app tells me their are 192 uncategorized calories.

Using the 1405, I get 16% fat, 68% carbs and 16% protein - the same as Fitbit.

Using 1581 I get 14% fat, 60% carbs and 14% protein not quite as close. Which means that Fitbit is not going to play the guessing game with the unknown calorie sources.

Remember that there is always going to be a bit of rounding going in most of the steps involved with the calculations. In this case, no rounding error between me and Fitbit.

In fact, here is that day from my spreadsheet.

And the formula for Column E:

=(D62*4)/((D62*4)+(F62*9)+(H62*4))

So anyway, it seems like the Fitbit numbers are pretty believable.

If you need any clarification or this explanation makes sense, please post a reply.