Are potatoes really that bad?

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hoosegow
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Post by hoosegow » Tue Dec 01, 2009 10:01 pm

I feel like I'm being difficult here, but I'm not trying to. Maybe I need to get an understanding. Yall remember I'm just a dumb farmer. You are telling me that a calorie - by definition is the amount of heat required to raise 1 g of water 1 degree Celcius - is measured differently from one country to another.

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stuward
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Post by stuward » Tue Dec 01, 2009 10:10 pm

A food calorie is not the same as the unit of energy.

http://en.wikipedia.org/wiki/Food_energy

Generally when some one says that a calorie is not a calorie, they're talking about the effect that different macro nutrients have on hormones in the body.

http://www.ajcn.org/cgi/content/full/79 ... b08a678686

hoosegow
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Post by hoosegow » Tue Dec 01, 2009 10:23 pm

Dang it! I did learn something:

The amount of food energy in a particular food could be measured by completely burning the dried food in a bomb calorimeter, a method known as direct calorimetry.[4] However, the values given on food labels are not determined this way, because it overestimates the amount of energy that the human digestive system can extract, by also burning dietary fiber. Moreover, not all food energy eaten is actually resorbed by the body (fecal and urinal losses). Instead, standardized chemical tests or an analysis of the recipe using reference tables for common ingredients[5] are used to estimate the product's digestible constituents (protein, carbohydrate, fat, etc.). These results are then converted into an equivalent energy value based on a standardized table of energy densities

This I did not know. Now things are starting to make sense. The cooking of the potato changes the digestibility of the nutrients in the potato. The cooling of the potato, as per wouter, chrystilizes the starch making it less digestible and thus lowers calories.

For what it is worth, NONE of this makes sense from a pure chemical definition, which is what I understood a calorie to be. Hopefully yall will forgive me for my misunderstanding. I couldn't understand where the additional matter was coming from. Now that I understand that a calorie on a nutritional label is not a chemical calorie, it makes sense.

For what it is worth, I know a calorie isn't a calorie in respect to the body's hormonal response. I was speaking strictly in a unit of measurement sense.

hoosegow
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Post by hoosegow » Tue Dec 01, 2009 10:27 pm

I'm generally excited I learned something. Thanks everyone!

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Post by frogbyte » Tue Dec 01, 2009 11:34 pm

I had a similar revelation recently, which spawned this thread http://exrx.net/forum/viewtopic.php?t=6069 where the revelation continued.

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Wouter
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Post by Wouter » Wed Dec 02, 2009 9:15 am

Hey hoosegow, I had to learn this for my exams, so thanks for making me write this up. Now I've learnt it while helping others :grin: (much more pleasant than studying)

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