Even if one is not interested in meticulous counting of calories, it is useful to know the amount of calories contained in the three different food types:

Carbohydrates :: 4 calories per gram

Proteins :: 4 calories per gram

Fats :: 9 calories per gram

For alcohol, the figure used is 7 calories per gram of 100 percent pure alcohol.

All this of course is an oversimplification, but it’s okay to use these figures directly if one does want to count calories, as at worst you will be erring on the side of caution.

Nevertheless, it’s interesting to delve a little deeper:

Water, as we all know, contains zero calories. Also, the specific gravity of water is 1 (at 60° F or 15.6° C). One millilitre of water is equivalent to one gram of water. The specific gravity of other liquids varies. For example, most oils have a specific gravity ranging from .90 to .94 (or thereabouts). Olive oil is at .91 — this means that 100 ml of olive oil weighs 91 grams. The specific gravity of pure alcohol is even lower, about 0.8.

Interestingly, all foods contain some percentage of water. Even fats are made up of about 10 percent water. Further, unless you have a super-fabulous-mutant-ninja digestive system, some proportion of the food you eat will be unabsorbed and eliminated. For instance, this unabsorbed proportion for fats is considered to be 5 percent, on average.

That’s how the nutrition guys came up with the statement: “3500 calories equals one pound of fat”. Were you to do the actual math, you would calculate that 1 pound equals 454 grams; multiply this by 9 calories for each gram of fat and the result is 4086. Reduce it by 15 percent (water content + unabsorbed) and you get the approximate figure of 3500.

An immediate thought that comes to mind is that the absorption of fats (and other food groups) would perhaps be even lower if the food passes through the digestive system quicker. While this may not be entirely true (as some people may have more efficient digestive systems), it does somewhat stand to reason. In fact, this is exactly what happens when the component of insoluble fibre (roughage) is higher in the food intake. Insoluble fibre is eliminated as is, and also helps the quicker movement of food through the digestive tract. Of course, you can’t indiscriminately increase the component of fibre in your diet — unless you’re prepared to shift residence permanently to the toilet.

There’s lots more to be aware of when it comes to calories and food groups, but I guess it would be easier to digest, both for you and for me, in bite-sized posts!

(More on this subject later).

- Val Souza

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3 comments to Calorification

  • Yes, you will be privy to everything, Russell. Progress will be monitored and published every 10 days up until the end of 100 for 100. The Progress Report for Decade One is here.

    Decade Two ends on March 6th. Do check back on the 7th for the second progress report
    - Val

  • Russell

    BTW on the 27th will we be privy to the results of your 10th day journey to 73.

  • Russell

    It is so good to notice that your B.Sc. degree in Life Sciences-Biochemistry is coming into real personal use at this stage of you life. I’m sure you would have not dreamed this was the reason for your degree in your 56 kilo days!!!
    Walk some more while pondering a blog post on ‘Those were the days my friend” and wondering if Scientific Writing could be your next venture as a journalist!!!

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