A physicist decides to go on a diet. He is told to "reduce his caloric intake by 1000 Calories per day". He calculates that all he needs to do is to lower the temperature of his four daily cups of coffee by 1 C^o to achieve his goal!

From the definition of 1 cal as the amount of heat needed to warm up 1g of water by 1 C^o, he calculates that exactly 1000 cals are needed to warm up 4 x 250g = 1000g, or one liter of (watery) coffee by 1 C^o

Is this all there is to dieting?

Thanks to Walter Hardy for this true story.