I use a program called Samsung Health to enter my calories each day, to try and keep in a healthy range. But how do you calculate the calories in a Big Mac? I remember reading about a bomb calorimeter many years ago where you literally burn the food, and measure temperature change in the surrounding water. When I Google for calorimeter, it appears this still the method used.
This seems suspect to me. Not every part of a Big Mac (or even a carrot) will be converted to calories in your body. Otherwise, the fiber that passes through you would not do so.
There are apparently ways to weight the bomb calorimeter readings for different food types, like fiber. The
Atwater system is in dispute but widely used for these adjustments.
McDonalds (and the other large chains) are required by law (I believe) to offer their nutritional data. At any rate, the signs usually list the total calories of the item.
ReplyDeleteWhere it gets complicated is when you mix and match: For example, I will usually get two double cheese burgers, combine them into one bun (for a 4xcheese burger?) and dispose of one full bun - which has a majority of the calories and carbohydrates.
All true. Note that dry feces will burn. (E.g. cowboys cooking over a fire of "buffalo chips".) That means there is energy of combustion remaining in the material - i.e. calories.
ReplyDeleteSo I have to include feces in my daily calorie count?
Delete> But how do you calculate the calories in a Big Mac?
ReplyDeleteIn general, poorly.
My wife works for the company that writes the "Carb Manager" app (https://www.carbmanager.com) which is a calorie and "macro nutrient" app, and I've been interested in this stuff for a long time.
Calorie counts are an estimate, and The Government allows (IIRC) a 20% variance in listed calories (+/- 10%).
In addition, different things are processed differently and have a different "cost" to turn into glucose or fatty acids. Simple sugars (glucose, sucrose etc.) take no energy to process, while fats need to be broken down into fatty acids before absorption and proteins need to be processed into amino acids. And of course longer chain carbohydrates known as "fiber" (soluble and insoluble) DO contribute to energy in a bomb calorimeter, but provide little if any calories to a human body (though they do feed the bacteria in the gut, and MIGHT contribute some butyrate, but this will vary by individual.
On the other side, it's nearly impossible for a "free living" human to calculate energy expediture in a useful way. I have a polar fitness watch, and use an android phone running "map my run" to track daily exercise ranging from dog walking to rucking, running, stretching, cycling, swimming, etc.
The calorie estimates between the two are never even close, and the best you can do outside a lab has a 10 percent margin of error.
So really calorie counting is mostly three things:
1. It makes you cognizant of your serving sizes.
2. The Hawthorne effect. You know someone (you) is watching, so you are more careful what you eat.
3. IF you keep your weekly calories consistent and are losing weight you know you are in deficit. If you are gaining weight you are not. Then you can alter your intake or output accordingly.
Which is to say "don't sweat the details".
Also note that if you are doing resistance training (e.g. weight lifting) and you NEED to be doing resistance training, you might be adding muscle mass, which means your weight may be staying the same while your body fat drops.
You might find this interesting: https://pmc.ncbi.nlm.nih.gov/articles/PMC3605747/
IMO the best thing to, ESPECIALLY for those of us over 50, is to prioritize protein (100g a day) and fiber (25-30g a day) which--if gotten from "real" food" will cover the limited fat intake we need (after all, we've got a lot of that stored, no?) and you don't really *need* carbs, other than chocolate.