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13 March 2013

Content of M-foodstuffs

I: INTRODUCTION : A SCENE AT A CERTAIN FAST-FOOD RASTAURANT

After loitering around the entrance of the restaurant, it is finally the start of the interval of time for their "value meals". Without too much notice, I realized people started flowing in from all over, like flies around a newly-discovered feast, the queue started to accumulate into a lengthy stream. Finally, when it was my turn to place an order: "Double cheese set, medium, makan sini, tukar Coke kepada Milo ais, terima kasih."

That was almost the routine most of us will find around that kind of shop around this country. Upon orders, they will quickly lay a tray on the counter, pat on a piece of advertisement paper which also serve as a ready-to-throw dining mat. He/she then will push the tray to your right, while the other colleague robotically put down the things that we have ordered.

So we carry that stuff, laid it on an empty table and started to sink our teeth to our merchandise while perhaps reading an article or watching an anime with our smartphone. How many of us actually read the ads on the paper mat? How many of us actually paid attention to say, that piece of "nutrition information", so much listed (albeit not detail enough) under the line "As part of our commitment in promoting 'Balanced, Active Lifestyles'"?

I did. For as much effort spent on eating, I noticed the list wasn't exactly complete to describe all the necessary information on the chunk of matter we put in our mouth. Nonetheless, I brought the list home, and spent about 30 minutes to perform a quick analysis to the information that was provided by the big M we all love.

Now, in order to understand how long it takes to burn the energy contained in the materials we eat, we need to understand the simple concept of the Harris-Benedict equation and its estimation of Basal Metabolic Rate (BMR).

II: THEORY FOR CALCULATING ENERGY EXPENDITURE

How fast a person spend his/her fuel, i.e. food, depends highly on the persons' metabolic rates. The basal metabolic rate, or BMR, provides the amount of energy needed daily to keep the person surviving without activity. In 1919, James Arthus Harris and Francis Gano Benedict [1] published "A Biometric Study of basal Metabolism in Man" included two equations to estimate this BMR for both male and female. In 1984, the equation was revised by Rosa and Shigal [2] to accommodate the change of statistics throughout the years since 1919. The revised Harris-Benedict equations are able to estimate BMR for both male and female, and similar to the previous un-revised formulae; it is dependent on age, height and weight.

The revised Harris-Benedict equations:
BMR (men): 88.362 + (13.397*w) + (4.799*h) - (5.677*a) [kcal/day]
BMR (women): 447.593 + (9.247*w) + (3.098*h) - (4.330*a) [kcal/day]
w = weight in kg , h = height in cm , a = age in years

Now, the BMR only shows the energy per day needed for that particular person just to be kept theoretically alive. To calculate the "true" calorie needs for an adult for a day based on how much things he/she does, we need to multiply BMR to the amount of physical activity he/she typically does in a dimensionless index called "physical activity level" or PAL.

Depending on our lifestyle, the PAL was estimated by FAO/WHO/UNU consultation reported in 2004:

Sedentary: office worker with little or no exercise: PAL = 1.40 to 1.69
Moderately active : a person running an hour on daily basis: PAL = 1.70 to 1.99
Vigorously active: a person swimming two hours on daily basis: PAL = 2.00 to 2.40

III: MALAYSIAN STATISTICS

So, how this all relates to the nutritional facts we have previously obtained? Well, the fact-list provided food name and its corresponding amount of energy. So with an average BMR of a Malaysian population, we can compute simply, the time it takes to "burn" the energy contained in a typical McD meal depending on his/her typical physical activity.

According to an academic report [3] titled "Obesity in Malaysia" by M. N. Ismail et al. in 2002, published in Obesity Reviews; 409 ethnically diverse, 18 to 60 years old, healthy Malaysian adults were taken from a population of 1165 urban and rural subjects to calculate the BMR, PAL and consequently, the average total energy needed per day (TDEE).


Since our study focuses on popular fast-food restaurant in urban setting, we will cite the BMR, PAL and total energy expenditure per day (TDEE) in an urban population sample based on that 2002 census.


From the report, we have:

MALAYSIAN (URBAN MALE)
(sample size, n = 117)
BMR: 1342.6 ± 133.8 kcal/day
PAL: 1.65
TDEE: 2224.2 ± 430.0 kcal/day

MALAYSIAN (URBAN FEMALE)
(sample size, n = 83)
BMR: 1139.6 ± 102.7 kcal/day
PAL: 1.60
TDEE: 1825.2 ± 286.7 kcal/day

This enable us to calculate, simply by dividing the calories in food with the TDEE to estimate how long it takes for our body to burn a typical McD order.

IV: COMPUTATIONS AND BRIEF ANALYSIS

Of course, because the value of TDEE  is different for different sex, age, height and weight, so given the formulae, one can even calculate the TDEE for oneself given sufficient knowledge of his/herself. However, since we are trying to calculate the general TDEE for typical urban dwellers in Malaysia, we will employ the results by M. N. Ismail et al. in 2002. From that study, it was found that Malaysian female has relatively lower PAL compared to male, naturally we will have a result that shows it takes more days for a typical Malaysian woman to  burn off the same meal compared to a typical Malaysian male of urban setting.

Here's the tabulated results. The result is quite self-explanatory. 

CLICK IMAGE FOR CLEAR VIEW

The first column is the list of name for the McValue Set (Medium) meals, in which its "Total Energy" and "Total Carbs" are the sum of values given by the food itself, a medium serving of french fries and a medium serving of Coke. Total solid mass indicates the serving size of "solid" food. i.e. excluding drink. The table is arranged based on the time it takes for the consumer to burn off the meal in ascending order as indicated by MALE (Hr) and FEMALE (Hr). Hr is an abbreviation for "hour" meaning, the hours it takes for the McValue set to burn off.

Colours in the table indicate green is favourable and red being least favourable. i.e. for fat and carbohydrate (abbreviated to carbs) higher values are indicated as red, and for protein, the lower value are indicated as red.

We need to note that Ayam Goreng (both regular and spicy) appears to have the least amount of carbs and fat owing to the relatively low serving size because the estimation was using 100 grams of Ayam Goreng as example. In reality, the edible quantity will be more than 100 grams.

From the data, it seems that the price of McValue set seems to increase with the total energy content. However, set meal with higher calories doesn't mean it is "heavy". As such, to "fill" up the stomach, one might opt for the set with highest mass, which is Big n' Tasty. It is slightly cheaper than Spicy Chicken McDeluxe and it also contained relatively lesser carbs, not to mention the second highest in protein content. The drawback is the amount of fat it contains.

Personally, I would opt for double cheeseburger.


References:
[1] J.A.Harris, F.G.Benedict, "A Biometric Study of Human Basal Metabolism", Proceedings of the National Academy of Sciences, Vol. 4, No. 12, 1918, pp.370-373
[2] A.M. Roza, H.M. Shizgal, "The Harris-Benedict Equation Equation Reevaluated: Resting Energy Requirements and The Body Cell Mass.", The American Journal of Clinical Nutrition, 40, pp:168-182
[3] M.N. Ismail et al. "Obesity in Malaysia", Obesity Reviews, 2002

Disclaimer:
The author of this post is not a nutritionist, neither he had any training whatsoever in clinical nutrition. The reader must strictly refer to a professional nutritionist for consultation if clarifications are needed on dietary information provided by the mentioned establishment. This article only serves as a casual reference and its accuracy might be subjected to errors due to factors the author is not aware of.  

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