Thermgenic Effect of Food

CBedzz · April 2018

It's my first day with cronometer, so just learning everything, but the firt thing I noticed was that for calories burned it only had activity and BMR. Shouldn't there also be a TEF (thermogenic effect of food component)? This can add a significant amount to the daily burn, especially if there is a high protein percentage.

Thanks for the great resource, and thanks for the help,

CBedzz

Susan_RD_101 · April 2018

@CBedzz

Welcome to Cronometer! Happy to have you join the discussions.

The thermic effect of food is ~10% and is more or less accounted for in the equation that is used to calculate the Basal Metabolic Rate, Mifflin St. Jeor.

Kind regards,

CBedzz · April 2018

Correct me if I'm wrong, but TEF (also called specific dynamic action) can be calculated in a number of ways, the most commonly accepted probably being Mifflin -St Jeor, along with Harris-Benedict, or Katch-McCardle (which uses lean body mass instead of total body mass). They use age, gender, current weight, and height (along with fat free mass for K-M) to calculate your BMR. Yes, you can add a multiplier to try to guesstimate your daily burn, but from the research, they do NOT measure TEF, and are not functions of calories ingested. TEF is a function of the total calories you eat, and how much energy the body itself needs to break down those foods. Common estimates of fats and carbohydrates are 5-15% which would jive with the 10% you mentioned, but proteins are much higher, with some research suggesting up 20-30%, well higher than 10%. A diet high in proteins could have a much bigger TEF contribution to overall daily burn.

I believe it's fairly well accepted that total daily calorie burn is a function of totaling BMR (basal metabolic rate), NEAT (non-exercise activity thermogenesis), TEA (thermic effect of activity), and TEF (thermic effect of food).

In a program such as Cronometer whose strong suit seems to be analytics and accuracy, to suggest TEF is "more less accounted for" in BMR seems counterproductive and inaccurate.

Just my two cents. Love to hear other's thoughts.

moies · April 2018

I've often wondered about this, thanks for raising it. Theoretically, my activity tracker supplies the NEAT and the TEA.

It's kind of ugly conceptually, but one workaround would be to deduct the TEF from the calories a food contains. But my guess is that there is already lots of error in all the numbers to start with. Two different 100 grams of broccoli could have very different water contents and everything else. And the idea that my activity tracker is accurately measuring my calorie burn also beggars belief.

I think at best these numbers can be used for trends and comparisons: Am I moving more than I did last month? Am I consuming more?

Susan_RD_101 · April 2018

@CBedzz

I appreciate your comment and taking a more in-depth look at this. You are right in that total energy expenditure = BMR x TEF x NEAT X PAL. However, BMR can only be measured under strict laboratory conditions. Thus, most researchers use an RMR or resting metabolic rate, which is ~10% higher than a BMR (on average). As such, if we are calculating an RMR (which MSJ does), the calories from a TEF can be somewhat accounted for.

Unfortunately, this loss in accuracy isn't a fault of the program, but shows the challenge in obtaining individual energy expenditure data. However, if you are able to obtain this information, you can set your own calorie target, rather than use the default that is calculated for you.

Anecdotally, when I had access to an indirect calorimeter and could measure RMR, I found that MSJ was the most accurate of formulas.

Hope this helps!

Kind regards,

moies · April 2018

For those of us who fast intermittently, it would actually be quite cool to be able to analyze this stuff. I fully understand that no food tracker does this currently. I also do keto on top of intermittent fasting, so, conceivably, TEF plays an even larger role for me.

For every food in the database a TEF adjustment could be calculated (estimated) based on the weight of carb, fat, and protein within it. You then give the users the option to adjust calories burned for TEF.

Of course there is still environmental temperature, food temperature, and the conversion of calories to ATP to take into account.

Susan_RD_101 · April 2018

@moies

For sure! Great idea... I would definitely suggest this in Features to see if the team would be able to do something like this.

Kind regards,

Thermgenic Effect of Food

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