Obesity and Economics

Economics has been said to be a study related to "monetary matter", but as once Gary Becker said, it seems more precise to me that economics is a study related to "human behavior". From this viewpoint, monetary matter could be causes and results of human behavior.

In this respect, economics could tell why people get obese(*):

When people decide to take in meal, they must compare the present benefit from eating today to the present cost of being obese tomorrow. However, when thinking about the present benefit from eating today, we have to subtract the cost (time and money spent on eating food) from the utility obtained by eating food today because we would be more likely to be obese if we could eat more meal at lower cost. The lower cost of meal would probably make us obese.

In this point, "the cost of meal" is one of the most important factors to determine obesity. From the experience of the United States, the lower the cost of taking in calorie, the more likely for people to be obese.

Regarding the present cost of being obese tomorrow, people's preference for obesity avoidance could be also related to how obese people would be, and thus how patient people are. In economics, it is named people's "time preference", "discount rate" or "ratio of patience": more impatient people are less likely to stand up their hunger because they discount more the cost of being obese tomorrow.

When we think about obesity, time preference can be a key term!

It can be derived by asking the following two questions:

(1)What rate of interest would you request 1 year later if your $100 were put in a checking account?

(2)What rate of interest would you pay 1 year later if you borrowed $100 from your friend?

Regarding the interest rate derived by asking like (1), the higher it is, the more impatient people are. That is, the more impatient people are more likely to be obese because they discount more the risk of being obese in their future. In fact, one research conducted by Osaka University tells that the more impatient people have higher BMI.

Note that BMI stands for Body Mass Index and (BMI) = (weight; kg)/(height; m)^2 and obesity tells (BMI) is more than 25. Moreover, in Japan the BMI of the men at any age and the women at elder age has been increasing for 20 years.

Also, regarding the time preference derived by asking like (2), is it the same as one that they get when they make a deposit? The time preference earned by making a deposit is reported to tend to be higher than one paid by running up a debt.

It should be natural, though. Interestingly, the larger such difference between the two interest rates, the lower the BMI people have. It could be easier to think about the reason:

We assume that "obesity" be seen as "debt" and so we can understand that we would have to pay higher interest rate(higher cost of being obese) if we accumulated a debt called "obesity".

Thus, people who don't like paying such higher interest rate are less likely to be obese.

In Japan, women are reported to be less likely to be obese than men and two reasons can be considered for this trend(**):

(1)The difference of women between the two interest rates is larger than that of men.

(2)Women are less impatient than men.

To sum up, the above study tells that "obesity" can be explained to some extent by the idea of "intertemporal choice".

[Note]

(*)The above study comes from the article written by Prof. Shinsuke Ikeda of Osaka University (in Japanese). However, it is summed up by Taro, so any mistake is due to Taro.

(**) Another reference is here.