Cal or Kcal

[Fritz Holhkopf]

Hi,

I realized that the energy spent for the same workout is shown with different units in Ergdata and Apple Health. ErgData’s unit is in cal, whereas the same workout exported to Apple Health is shown in kcal.

For example: ErgData: 57 cal, Apple health: 57kcal.

I guess the units in AH are correct. But I am not sure.

[JaapvanE]

I'm not sure about that one to be honest. My last session was around 1200 calories according to Garmin, for a half marathon.

[Sakly]

I'm not sure about that one to be honest. My last session was around 1200 calories according to Garmin, for a half marathon.

I'm very sure the unit is given in kcal, not in cal.
Calorie is a heat unit and defines the energy needed to heat up one gram of water about one degree.
Do you think you "wasted" the amount of energy needed to heat up 1,2l of water by one degree in 1 1/2 hours?

Anyway, the calorie thing doesn't work for the body, as the body is no combustion engine and does not "burn" calories.

[Tsnor]

Anyway, the calorie thing doesn't work for the body, as the body is no combustion engine and does not "burn" calories.

Your body does burn (oxidize) fuel and make waste heat as well as work done. If you take watts, assume about 25% efficiency and convert unit you get pretty close to the reported kcal.

Note calories is case sensitive. "Calories are referred to as either small (lowercase “c”) or large (uppercase “C”), with 1 large Calorie equalling 1,000 small calories. Scientifically,1 kcal or kilocalorie is equivalent to 1 large Calorie or 1,000 calories."

[JaapvanE]

Note calories is case sensitive. "Calories are referred to as either small (lowercase “c”) or large (uppercase “C”), with 1 large Calorie equalling 1,000 small calories. Scientifically,1 kcal or kilocalorie is equivalent to 1 large Calorie or 1,000 calories."

Your kidding.....

Probably not. This is highly confusing. Garmin reports Calories (so 1200 kCal for a HM session).

[gvcormac]

Americans use Calorie (capitalized) as a synonym for kcal. So one Calorie is 1000 calories.

[Sakly]

Anyway, the calorie thing doesn't work for the body, as the body is no combustion engine and does not "burn" calories.

Your body does burn (oxidize) fuel and make waste heat as well as work done. If you take watts, assume about 25% efficiency and convert unit you get pretty close to the reported kcal.

Sure, the reported calories are based on experience what to expect on average, not based on actual oxidized fuel. A watch on your wrist cannot measure that, neither a rower can.

[JaapvanE]

Sure, the reported calories are based on experience what to expect on average, not based on actual oxidized fuel. A watch on your wrist cannot measure that, neither a rower can.

Indeed. The formulae used are riddled with assumptions. Major ones are weight (C2 assumes a 300kJ/hour for being alive and moving up and down the slide) and human efficiency (which might be way off due to poor technique). Grains of salts should be taken when using these readings.

[iain]

All down to the diet industry referring to the kcal that would be produced on complete combustion of the food concerned as "Calories" I believe.

[Sakly]

All down to the diet industry referring to the kcal that would be produced on complete combustion of the food concerned as "Calories" I believe.

Absolutely.
The calorie counting is complete garbage, but many are following this approach not understanding how the body metabolizes the food compartments.

[iain]

Absolutely.
The calorie counting is complete garbage, but many are following this approach not understanding how the body metabolizes the food compartments.

Despite studying uni biochemistry, I didn't know the quantitative differences between food sources. Clearly less "energy" is extracted from proteins, but these are the smallest of the food groups for many. Looking at the ratio of what the bodies extraction of energy from fats and carbs is to the "Calories" in them:

1 molecule of glucose (180g/mol) yields 38 ATP, 1 mol per 4.7g. 1 Molecule of saturated 18 carbon fatty acid (284g) yields 120 ATP (per https://www.ck12.org/flexi/physical-sci ... 20%2B%2090) So 1 per 2.4g. Full oxidation yields 9 Cal/g for fat while 1g carb is 4 Cal, so body ratio is about 2:1 while the "Calories" are in ratio 2.2. So counting calories is a reasonable approximation of the energy available for these major food groups.

Of course there are differences in the impact of fat and sugars on the body that will influence whether people over eat, also large amounts of carbs are converted to fats for storage which means that the "calories" stored for carbs is proportionally less than that used or stored short term as glycogen (perhaps making the 2.2 ratio closer for some than the 2 calculated above). But broadly these calcs suggest that (ignoring protein that WIkipaedia estimates to be 15% of all calories) there is broadly equivalence between Calories absorbed. So Cal in minus Cal used has some use. Of course the "Cal" of the calculation a re not the same to physical kcal of energy produced due to the inefficiences of our use (usually estimated at 25% efficiency), but so long as energy used is grossed up in the same way, this should not invalidate the formula.

So I think calorie counting is useful, but people should realise that the ease of adhering to a diet will be influenced by what they eat not just the calories and that the "2200Cal/day" is an average that needs to be estimated more precisely to be compared with the Cal in.

[Sakly]

Absolutely.
The calorie counting is complete garbage, but many are following this approach not understanding how the body metabolizes the food compartments.

Despite studying uni biochemistry, I didn't know the quantitative differences between food sources. Clearly less "energy" is extracted from proteins, but these are the smallest of the food groups for many. Looking at the ratio of what the bodies extraction of energy from fats and carbs is to the "Calories" in them:

1 molecule of glucose (180g/mol) yields 38 ATP, 1 mol per 4.7g. 1 Molecule of saturated 18 carbon fatty acid (284g) yields 120 ATP (per https://www.ck12.org/flexi/physical-sci ... 20%2B%2090) So 1 per 2.4g. Full oxidation yields 9 Cal/g for fat while 1g carb is 4 Cal, so body ratio is about 2:1 while the "Calories" are in ratio 2.2. So counting calories is a reasonable approximation of the energy available for these major food groups.

Of course there are differences in the impact of fat and sugars on the body that will influence whether people over eat, also large amounts of carbs are converted to fats for storage which means that the "calories" stored for carbs is proportionally less than that used or stored short term as glycogen (perhaps making the 2.2 ratio closer for some than the 2 calculated above). But broadly these calcs suggest that (ignoring protein that WIkipaedia estimates to be 15% of all calories) there is broadly equivalence between Calories absorbed. So Cal in minus Cal used has some use. Of course the "Cal" of the calculation a re not the same to physical kcal of energy produced due to the inefficiences of our use (usually estimated at 25% efficiency), but so long as energy used is grossed up in the same way, this should not invalidate the formula.

So I think calorie counting is useful, but people should realise that the ease of adhering to a diet will be influenced by what they eat not just the calories and that the "2200Cal/day" is an average that needs to be estimated more precisely to be compared with the Cal in.

Your explanation clearly shows the focus of the macros is based on their calorie content, not on their function in the body and how these macros are absorbed. That's the main "fault" in these discussions.
Protein is a building block. The body is able to get energy from it, but tries to avoid, as it is very inefficient. So does it make sense to add the measured heat energy to the energy content available for the body?
Fat is both a building block and energy source. Same question, does it make sense to add the whole measured heat energy to the energy content for the body?
Another factor for fat is the bodies ability to absorb it. It needs bile to absorb it and there is only so much bile to absorb fat, so not all consumed fat can be absorbed, if above a certain range. Same question, does it make sense to add the whole measured heat energy to the energy content for the body?
Carbs are not used as building block and need to be oxidized for energy or converted to fat for storage. They are typically well absorbed and produce massive problems, if consumed in high amounts.

2000kcal from fat = 2000kcal from carbs = 2000kcal from protein?
Clearly not.

[iain]

Your explanation clearly shows the focus of the macros is based on their calorie content, not on their function in the body and how these macros are absorbed. That's the main "fault" in these discussions.
Protein is a building block. The body is able to get energy from it, but tries to avoid, as it is very inefficient. So does it make sense to add the measured heat energy to the energy content available for the body?
Fat is both a building block and energy source. Same question, does it make sense to add the whole measured heat energy to the energy content for the body?
Another factor for fat is the bodies ability to absorb it. It needs bile to absorb it and there is only so much bile to absorb fat, so not all consumed fat can be absorbed, if above a certain range. Same question, does it make sense to add the whole measured heat energy to the energy content for the body?
Carbs are not used as building block and need to be oxidized for energy or converted to fat for storage. They are typically well absorbed and produce massive problems, if consumed in high amounts.

2000kcal from fat = 2000kcal from carbs = 2000kcal from protein?
Clearly not.

I think when people are focusing on the body building aspects of macro nutrients they measure by weight of that nutrient, personally I have only known Calories discussed in terms of weight or fueling, hence not considering the building aspects of them in a discussion of Calories.

I attempted to make it clear above that protein is different and I agree that excluding it from calories would be an improvement. However calorie counting goes back further than our understanding of the bodies biochemistry and excluding the protein would mean resetting standards and a more complicated analysis rather than the simplicity (of understanding and measurement) that calorie counting has. For adults building will be a small minority of the fat used in all but the most extreme situations as itr takes many days of concentrated effort to build a pound of lean tissue but only one to burn it as food. As such for most I believe ignoring the amount used for building will only normally be an issue is an essential fat is largely omitted from the diet. For body building the discussion is different. I understand that body builders deliberately eat excess to bulk up then attempt to lose the excess while losing a smaller amount of the muscle than was produced when bulking up. As a result calories are not focused on in the first phase and in the second the building is relatively small (as anabolism is promoted by insulin that requires sugar and promotes its conversion to fat stores).

[Sakly]

Sure, you pointed out protein is different, but fat is as well. It is used to build cells, hormones and other stuff in the body. This is why it is vital to eat fat, but not to eat carbs (even though we need carbs to survive, but no exogenious).

The main thing is, measurement of calories isn't even possible. Not on the "input" side, neither on the "output" side.
Food is allowed to deviate 20% from the label, so you get a 40% range of the calories from the label. Good luck to calculate your input. For the output you need to know how much of that food matter is oxidized by your metabolism. How? Believe in your watch? It cannot even measure my heart rate properly...

In the end it comes down to "tracking" your amount of food and your weight, adjust input according your goals, that's it.

[gvcormac]

There's a whole lot of dogma in this thread.

There's a fundamental law of thermodynamics that says if you consume a certain number of calories of fuel, you'll either burn them or excrete them. Except for fiber, you excrete very few of the calories you consume.

Some sources of calories (protien) require energy to consume. So a protein calorie, all things being equal, generates about 1/3 of a calorie of heat in the process of being digested.

"Calorie counting" is largely fruitless because it is done wrong. Just like budgeting. But you should be aware of calories, just as you should be aware of the price of things you're purchasing. If you are gaining unwanted weight, you should consume fewer calories; if you're spending more than you earn, you should purchase less. A calculator is not required. Just a course correction.