Friday, January 05, 2007

Calories and so on

How much is 200 calories actually? Well, it's about 800 joules. What is a joule?

As a rough guide, 1 joule is the amount of energy required to lift a one kilogram object up by a height of 10 centimetres on the surface of the Earth.


The energy required to lift a small apple (102 g) one meter against Earth's gravity.


In chemical energy stored in food.

Goodies: Celery (Apium graveolens dulce)
It is sometimes grouped as a low-calorie fibre bulk food. Not only does eating it will result in very few calories (actually negative, because digesting it requires more energy than the celery contains), it has a lot of vitamin C and fibre.

Baddies: Bacon (Sus scrofa domesticus)
Ewww.... I hate bacon. Not only does it tastes gross, it is full of fats: saturated, and worse unsaturated. Out of unsaturated fats, there are cis and trans fats (cis-trans or geometric isomerism - if you take chemistry).



Now it's the trans fats that we all talk about. Even your grandparents know what they are. Trans fats are bad for you! And indeed they are. It's all down to geometric isomerism. The C=C double bond in the trans isomer of the fat cause its rigidity and high density and make them hard to remove out of your body. I say they stay in your body forever (well a very long time)!

Anyways, some biology, some chemistry, some physics for you. What a happy post!


chumly said...

That is the most beautiful picture of celery I have ever seen.

Anonymous said...

Crazy stuff.. :)