Where did Cronometer get the coefficients for calculating the Thermic Effect of Food (TEF) calories?

omegaterus

I am very much interested in the Thermic Effect of Food (TEF) feature, because up till now, I have been myself adding a custom "exercise" to add a burn of 0.1912 kcal per gram of consumed fat, and 0.8126 kcal per gram of consumed protein (none for carbohydrate), which are the values from Geoffrey Livesey, Review article: A perspective on food energy standards for nutrition labelling, British Journal of Nutrition (2001), 85, page 274, which I post the relevant screenshot from below:

DOI: 10.1079/BJN2000253

Note the values in the above table are in kJ, so I divided them by 4.184 to obtain values in kcal (food calories). The coefficient is the difference between NME and ME in the above table.

So for fat:

(37.4 − 36.6) / 4.184 ≈ 0.1912 kcal/g

And for protein:

(16.7 − 13.3) / 4.184 ≈ 0.8126 kcal/g

With Cronometer TEF if I add a 1000 grams of pure fat to an empty diary day, it only adds 15.7 kcal TEF, while from Livesey it should be 191.2 kcal, why is the value Cronometer adds 12.2 times lower then I was using?

If I add 1000 grams of pure protein, Cronometer adds 253.8 kcal TEF, and from Livesey's data it should be 812.6 kcal, so Cronometer seems to add 3.2 times less.

Where did Cronometer get the coefficients used, which seem 12.2 x lower (for fat) and 3.2 x lower (for protein) then the coefficients quoted by Livesey?

Karen_Cronometer

Hi there,

There are a lot of factors that influence TEF beyond macronutrient composition in your diet, so we used average values found after completing a review of the literature.

The following values are used to calculate TEF in Cronometer:
7.5% of energy from carbs
25% of energy from protein
1.5% of energy from fats
16% of energy from alcohol

These values displayed are too low and I'm looking into the calculations now.

I'll let you know what I find.

Cheers,

Steverino

I must be missing something. Can I see somewhere in Crono the actual TEF values? Anywhere in foods or summaries or elsewhere?

Karen_Cronometer

When you add foods to your diary, once the TEF value is large enough to display as a fraction of your energy burned:

The TEF factors are applied to the macronutrient breakdown of the foods you've added to your diary, not to the foods directly. Though we could calculate this for each food for interest.

Steverino

Ah your screenshot answered my question -- I can a day's TEF by hovering over the Calories Burned / red slice. That's what I wanted to figure out. Thanks!

Steverino

One more question -- what is the calculation for TEF for each macro? Some % I presume?

Karen_Cronometer

The percentages are posted just above in this thread

7.5% of energy from carbs
25% of energy from protein
1.5% of energy from fats
16% of energy from alcohol

Karen_Cronometer

The TEF numbers are looking as expecting now, based on the numbers above^

omegaterus

Thanks, just checked the math of updated Cronometer code and comparison to Livesey's coefficients:

I put in an empty diary day 10000 grams of pure protein (from 45998 grams beef tenderloin custom food item from which I removed all the fat from and adjusted calories to only account calories from protein), and I am getting TEF 44049 kJ, so per gram of protein: 4.405 kJ/g = 1.053 kcal/g. Total energy from the protein is 176195.7 kJ, so TEF is now confirmed to be calculated at exactly 25.00% of energy from protein consumed. More-ever it seems Cronometer calculates total energy from protein at 17.620 kJ/g, so after subtracting the 25% we get net energy 13.215 kJ/g which is almost exactly the 13.3 kJ/g quoted by Livesey. Well done!

I also tried 99479 grams of fat (from 99999 grams a ghee custom food with the tiny bit of protein removed and adjusted the energy) and I got TEF 54945 kJ, so per gram of fat: 0.552 kJ/g = 0.132 kcal/g. While this is 31% lower then from Livesey who shows 0.8000 kJ/g = 0.1912 kcal/g, Cronometer calculates fat sourced energy at 36.822 kJ/g (not 37.4 kJ/g as Livesey), and after subtracting 1.5%, the resulting net energy is 36.270 kJ/g which is almost the same as 36.6 kJ/g NME quoted by Livesey. Great consistency here again!

Still out of curiosity, I would like to see a list of all the data sources the 7.5%, 25%, 1.5%, 16% coefficients were calculated from.

Ana_DA_BL

Hi, I have been reading in the literature that apart from macronutrient breakdown TEF is influenced by meal size in that one big meal will have higher TEF than the added TEF of having that meal divided into 3 intakes. Would your TEF estimates account for this? Thanks in advance!

AnonJohn

Thanks to Karen for posting the specifics. @omegaterus, you can read more on the literature here: https://forums.cronometer.com/discussion/4396/where-did-cronometer-get-the-coefficients-for-calculating-the-thermic-effect-of-food-tef-calories

Ana, interesting point on meal sizes. If you share the research and it's statistically robust, maybe they will implement it ...

Pangloss

It has been stated above that Cronometer uses the following estimates for TEF calculations:

"7.5% of energy from carbs

25% of energy from protein

1.5% of energy from fats

16% of energy from alcohol"

Are there any caveats? Are carbs net? Are different types of proteins or fats or carbs calculated any differently?

I assume Cronometer is not adjusting based on body fat percentage, meal timing, age, gender, etc., at this juncture, but I'm not quite getting the exact same TEF calculations as Cronometer shows in the app when I run my own tests based on grams of each nutrient type and these multiples.