Data Field: Fat Burner

I don't see a mention in this change list that they would have corrected the info.calories value, as it's not in my hands to fix this, you're best to follow up in this topic: https://forums.garmin.com/forum/developers/connect-iq/connect-iq-bug-reports/1244623-oregon-700-info-calories-is-not-correct (I've now asked for you)

Hi Peter,

I had already contacted you via 'contact developer' and also in the review before I spotted this forum. I do not want to flood you with my sentences through multiple channels, but I am really happy to see that somebody both had the necessary programming knowledge and the wish to add 'fat cal burnt' as a data field. I was really angry when Garmin delisted it, so only my old 310XT and 910XT could use my metabolic profile that could be uploaded with Garmin Training Center, but not my Fenix 3 HR.

It is really upto you to decide whether you wish to incorporate my experience gathered with respirometry tests or not. But if so then I can share all of my knowledge about it. If not, it is not a problem, the widget is your toy, you are the father, not me. :-)

For your kind attention I had the same sort of story with another developer and finally I could convince hime that his active calorie calculation had been not good, it had been just simply finetuned to himself. See version 5.91 at https://apps.garmin.com/en-US/apps/bfa0dd86-d947-45d7-832e-3ea36f5c4fba#0 and version 1.31 at https://apps.garmin.com/en-US/apps/1c5b10ed-20c1-4a49-9883-0153b7e30de1#0

hi Zoltan,

I understand that it would be easier for you to be able to input the values as a cal/min figure, but:
- I think that approach could result in fat calories / carb calories which are higher than the calories measured by the Garmin (so I'm not keen on adding it this way)
- I think the calories measured by Garmin should be kept as a base for the calculation of the fat/carbs calories.
- I would like to keep the configuration as easy as possible

Long story short: I'm ok with programming extra functionality, but I would prefer to keep the calories measured by the Garmin as the base value.

In a first phase I could offer configurable percentages for the values that are now hardcoded so that you can change these percentages to values that suit your experience better (eg Z1 = 100% fat => 80%).

In a second phase I could add a lineair progression so you can specify the low boundary values of the zone and that the app would do some interpolation towards the next zone value.

Would that work for you?

Sure, Peter, it would be highly welcome. It would be a good compromise between the present form of 'Fat Burner' and the ideal 'metabolic profile' approach of 310XT/910XT. And anyway it is a free tool, so I could be happy if I had to live with the few configurable HR zones (5 or 6, see below) vs the 21 HR ranges of the metabolic profile approach of the triathlon watches,

And certainly I understand your point of view about cal/min figures.

Just a question. What about the zone 0, Z0? I mean Z1 & Z2 & Z3 & Z4 & Z5 do not cover the whole HR range for those who eg use the modified Karvonen approach when defining their zones. I can imagine that since Fenix watches have only 5 HR zones, from a programmer's aspect it is not so easy to create any additional zones, otherwise you would end up with a complicated, fully configurable setting where user could define as many HR zones/ranges they would like. But as regards Z0, maybe it is easier to get there.

Could you retrieve and use the resting HR which is an item in the user profile setting of these watches? And using the resting HR and the low boundary values of Z1, practically Z0 would be born.

You actually enter a lower boundary for z1 in garmin connect settings so i can use anything below min z1 as z0. :)

I'm afraid it is not exactly the same. It is the same for phase 1, but in phase 2 when you are going to make it able to have a linera progression it is not the same to assume that Z0 is from 0 to the low boundary value of Z1 or from RHR to the low boundary value of Z1.

Hoi!

Beste Peter, may I have another question?

Today was the first day when I could use Fat burner during an activity. My finding was that summing up the calories from fat ('x' g multiplied by 9.0) and those from carbohydrates ('y' g multiplied by 4.0) does not give the total calories burnt.

First my idea was that you also assume some protein burnt ('z' g multplied by 4.0), too, but later I put this bet aside, because I thought you would have mentioned it in the description.

So if you only calculate with these two, and you explicitly declare that you use 9 kcal/g for fats, then the maths says that you likely use 4.5 kcal/g for carbohydrates which is not the accurate number.

I am just reading Essentials of Exercise Physiology from Katch-McArdle-Katch which says a lot about food energy. Note: exercise physiology is something like a hobby for me, so I read more books and researches about it.

1 g of pure lipid (that is fat) yields 9.45 kcal as gross energy value (that is heat of combustion got from the oxidation of food), but due the digestive and absorbing efficiency of human, which is 95% for lipids, one gets 9.0 as net energy (also called corrected heat of combustion or Atwater general factor.

1 g of pure CHO yields 4.20 kcal as gross energy value. The digestive efficiency of CHO is 97%, so the net kcal value is either 4.1 or 4.0. The exercise physiologysts always use 4.0 kcal/g for carbohydrates.

So I dont know why you use 4.5 kcal for CHO, but I am afraid it is not the correct value. To be honest I never saw any researches saying the carbohydrates yields 4.5 kcal per g.

Or am I wrong and you also consider some protein burning?

PS: the gross energy of proteins is 5.65 kcal/g. But since in the body of humans the nitrogen component of proteins does not oxidize, but they combine with hydrogen to form urea, therefore there is a loss of energy. Its extent is 19%, so we get to 4.6 kcal. Finally due to imperfect digestion (92%), the net value is also 4.0 kcal/g for proteins.

It was me who said Peter to put 4,5Kcal needed for count 1gr of carbs spent.
The idea was to consider the fact that not all the other calories we don't get from fat are just glucose... we also can get some energy (not from fat acids) using glicerol molecules released from triglicerids, and also, as you suggested, some protein depletion even when we still have glucose in the system.

Think on it as a way to avoid overestimate of carbs a little...

Also the proportions of each substrate used in every HR zone will vary with metabolic improvements due to training and still this methods are quite far of being accurate. But... is a littel help to know how much you burned carbs and when decide to eat something...etc

I understand your way of thinking, and I agree if the purpose is to tweak to get carbs as accurate as one cab, but it would have been more transparent to say the there are fat burning and "other". Or fat, carbs and protein.

But the present assumptions on fat share is really exaggerated, if you do not want to rely my own tetests just see eg https://www.brianmac.co.uk/mobile//esource.htm

And you are right, because not even the highly professional tests I participated measured the protein catabolism of my body at different HR rates, simply the RER in itself is not able to do that. We just know that the share of protein in calabolism is normally pretty low.

Anyway I was not the first but you were who jumped in and defined how the data field should work, so I make no additional effort to try to convince anybody.

But I do remember that Peter does not support the cal/min approach just to make himself able to get the Garmin calorie by adding fat calories and carb calories, and by using the tweak of 4.5 kcal for carbs this approach is nonetheless 'raped', since a naive user would calculate with 4.0 kcal/g for carbs and cannot get Garmin calorie. It is my way of thinking. Uff! :-)