Thermodynamics and Dieting!

Hi Guys,

One of my favorite subjects is Thermodynamics and as I was reading a book on Thermodynamics, I found this interesting concept.

Dieting is generally based on calorie counting. It is based on the concept of conservation of energy which is also the first law of Thermodynamics. People who consume more energy than their body burns get weight, whereas people who eat less will lose weight. But, we see people who eat more and yet remain slim. We also see people who eat less and are stout. So, where is the problem? Researchers come out with lot of theories.

Certain people have food efficient bodies and so they need fewer calories to do a work than others require. Our body interprets dieting as starvation and starts to use the reserve energy more stringently. For instance instead of eating 2500 calorie daily without exercise, the basal metabolic rate (energy spent during our rest time) reduces by 10-20 percent. If dieting continues for long periods, our body adapts to lower metabolic rate and if we start to eat normally again, we gain more weight than before.

So, moderate exercise is a part of healthy dieting program. It builds muscle tissue that burns calories faster than the fat tissues.

Another general hypothesis is that genes are the reason for overweight. Stats say that 80% of children of overweight parents are also overweight. So heredity is a reason for overweight. Researchers have found a gene called RIIbeta which controls the rate of metabolism. The genes keep the fat level at a set point (which differs from person to person). So if a person is going to gain weight, the metabolism becomes faster and if he is to lose weight, metabolism becomes slow. In this case, exercises don’t help very much.

If metabolic rate is low, the people must reduce in taking foods with high calorific value as it is the only option to avoid putting on weight. Exercises don’t help as metabolic rate is low.

There is something known as Sensible diet, which consists of two rules.   

1.  Eat whatever you want and whenever you want as much as you want provided that you do not eat unless you are hungry. 
2. You stop eating before you get stuffed.

Overweight leads to lot of health related problems ranging from high blood pressure to some forms of cancer especially if people have diabetes, hypertension and heart disease.

Listen to your body and don’t impose it.

Happy Reading!!!

P.S: This is an excerpt from ‘Thermodynamics: An Engineering Approach – Cengel, Boles’