Heart rate affecting caloric output? Macro and calorie counting help?

[DuuudeMaaan]

I'm new to Fitbit. Before buying the fitbit, I had projected that I would normally burn 2,200 calories a day, given my slightly below moderate exercise and my height weight etc. (M, 19, 5'9",142lbs). I did this using BMR and caloric output calculators. I therefore aimed to eat 2,400 calories a day, using MyFitnessPal as a calorie counter, as I want to build lean muscle at a slow but steady pace. I had all my macros adjusted accordingly and I was achieving my goal. 

After buying the Fitbit, I realised I have been burning more calories than that. Over the past few days, I'm averaging out a 2,500 calorie burn per day, and I can't keep up with the eating yet. I find myself stuffing in food at supper and after supper to hit my caloric intake goal. This is largely due to not knowing my caloric intake pace, and also due to my stomach not being big enough to eat so much.

It's worth noting that I have discovered my resting heart rate to range from 85-105 bpm, so my question is the following: Is my abnormally high resting heart rate making me burn more calories than I had projected with all the bmr calculators I have used in the past? Does this mean I need to re-adjust my macros? Should I really trust Fitbit's caloric output? Is it off w/in a hundred calories or five-hundred calories? All of this makes a huge difference to my diet, and a huge difference to my satisfaction with the product, so it would be greatly appreciated if someone could get back to me on this. 

*It's worth noting that I do not know if I am truly gaining muscle yet, as I am less than a couple of weeks into my lifting routine. I have a Charge 2 if that makes a difference.

[Dave001]

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@DuuudeMaaan wrote:

Should I really trust Fitbit's caloric output?

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Short answer: No. 

Long answer:

In the interests of transparency, I should state that I don't believe that counting calories is the most effective tool for most people's daily weight management needs.

That's not to say that I dispute the scientific evidence. It's apparent that if more calories are consumed than utilised, some will be stored as extra weight and vice versa.

However, the various different tools for estimating calorie usage are just that: estimates. There are so many variables in the field of calorie burn as to make those estimates of limited use in daily life. The margin for error is wider than the margin most of us would find useful on our weight management journey.

The efficiency with which we all turn our consumed food in to energy for life is also different. The fact that we could both sit down to a delicious meal of 500kcal together but both end up with different gains from it is something that the calculators can not take in to account.

So the simple truth is that we don't (can't) know how many calories we are taking in and we don't (can't) know how many calories we are burning. 

At at best we can believe that we have a reasonably accurate estimate. What that doesn't of course tell us is the margin of inaccuracy. Even a very narrow margin might just scupper our plans.

Let's use your example:

Your goal is to take in 2400kcal/day and burn 2200kcal/day.

If your well intentioned plan has a margin of error of just 5% in either direction, you could take in 2280kcal (2400 - 120) and use 2310kcal (2200 + 110).

As you can see, with even a modest margin, your best intentions can count for nothing.

Some good news:

Weight management in principle isn't very difficult!

We all know however that in practice it is extremely challenging, but through listening to our intuitive sense of self, exercising consistently and recording our food intake (and making small, incremental changes) we can all achieve our goals.

Good luck!