Friday, June 24, 2011

The Chalk Diet

If you drink a litre of cold water each day (say 2 almost full pint glasses), then your body expends energy to raise the temperature of this liquid to 37 degrees centigrade. 1 Calorie is the amount of energy required to raise a litre of water by 1 degree, so if we assume that tap water is at 8 degrees (as a year round average) then (37-8) = 29 calories of energy will be used by your body each day or 10585 calories in a year. (Purists please forgive me here- I know there are two different units called the calorie, but I'm using the same one throughout to keep things simple).

A gramme of fat gives up 9 calories when burnt, so you can lose 1.176 kilogrammes per year. This might not sound much, but think of it as just under two stones per decade.

Alternatively you could eat an extra 21 Big Macs every year without a second thought.

13 comments:

Anonymous said...

Try the same with cold beer. You ose even more weight...

Steve said...

Actually, a calorie is the amount of energy it takes to raise 1ml of water by 1 degree, not 1 litre. So that's a lot more Big Macs.

malc said...

There are short and long calories. One long calorie is the energy to heat one litre by one degree and this is what the food industry uses. He's been consistent so the math is correct.

pjt said...

No, it's not a lot more of Big Macs, because Mr. Chalk just mistakenly says "calorie" when he means "kilocalorie". There are no two different calorie units. kcal is just 1000 cal.

That part about losing weight by warming up beer in your belly is a popular urban legend, but unfortunately it does not work, even if you cool the beer down to sub-zero temperatures. Likewise with consuming energy by eating ice cream.

Anonymous said...

Frank is nearly correct.

The Calorie ( with a capital C) is 1000 calories ( woith a little c). He correctly defines it using a capital C but then forgets about the capital letter in the later part of his explanation. Otherwise it is all correct.

It isn't an urban myth, it's physics. Unless your urinate water at the same temperature you drank it, then energy has been used to heat it up. The heat energy needed to do this is generated by respiration which is fuelled by the food you eat.
So, for example, if you eat no food, and drink ice cold water, fat will ( by a complex process) be converted into energy to warm you, and the extra ice cold water. You would then lose weight ( about 8g).
1.9 litres of ice cold water would need about 70 Calories to warm it up.

Anonymous said...

pjt,

Beer or ice, yes it's a myth, because there is far more energy contained in the these.
However Frank is talking about water which has no calorific value apart from it's thermal energy.

Anonymous said...

This is good news, I drink a lot of water.
John Gibson

Suede Oasis said...

Will it still work with vodka? Or camel's urine?

Anonymous said...

It won't work Mr Chalk because you have not got any celebrity endorsement for the C-diet

Anonymous said...

It won't work Mr Chalk because you have not got any celebrity endorsement for the C-diet

Dack said...

Plus I reckon it takes a calorie to turn on the tap.

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