(b) Discussion
Food items included in the reference list are based on their availability at the Australian supermarkets, Coles & Woolworths in particular. Eating habits of Australian is also one of the concerns. For example, only untrimmed meats are included as because it may not be a common practice for Australian to eat trimmed ones. Saying that vegetables are served in raw and cooked, both types of data are entered.
When I am determining the serve size for each group, several factors are considered, including recommendations in guidelines, common serve size and convenience for estimation. Each food group is discussed in details in the following.
Bread and Cereals
I have assigned a serve size of 30g, which is a commercial serve for a piece of bread, for this food group. According to Diabetes Australia, 15g of carbohydrates in food can be counted as one carbohydrate exchange, which can be a piece of bread or 1/3 cup of cooked rice, etc (1). Among the grain products, however, bread is often consumed because of its ready-to-eat nature and it is also easier to quantify and visualize. Therefore, I adopt the serve size of bread over the others.
While whole grain products contain more protein, bread, cereals, crackers and biscuits have higher energy value among all. It is suggested that fats and sugar are added during processing. As for pasta, rice and noodles, they have less carbohydrate in average.
Starchy vegetables, vegetables and Legumes
A serve size of 75g is applied to starchy vegetables, vegetables and legumes because it is the suggested serve size on Australian Dietary Guidelines (ADG) (2). Other than that, size of 75g of different vegetables and legumes can be easily pictured by the help of available information on guidelines.
Starchy vegetables
Most of them contain 15g of carbohydrates per serve in general, whereas cassava outstands with 27.5g of carbohydrates. While green peas contain the lowest amount of carbohydrate, its protein content is the highest.
Vegetables
Most of the green vegetables have lower energy value, some of which can be as little as 28kJ per serving in celery. In contrast, snow peas, beets and onions get a higher energy profile, suggesting energy increasing with larger amount of carbohydrates. Brussel sprouts also attain a high energy value with its highest protein content overall. It is expected to see fat values of all vegetables are nearly zero.
Legumes
Among all, Lentil contains largest amount of carbohydrate and protein per serving. It is surprised to see that fat value of chickpea is >1g/serve.
Fruits
I adopt the standard serve size of fruit suggested in ADG as 150g (2), of which nutritional value is more significant to compare in some smaller size of fruits. I put the data of fruits according to their availability in Australian supermarket. Dragonfruit and logan are yet to be found in the database. Banana, with no doubt, has the highest carbohydrate values and energy value, following by the second highest Rambutans. It is interesting to know protein value in passionfruit can be up to 4.5g/serve.
Meats
To make my reckoner more generalizable, I try to cover meats from different parts of the animal, such as shoulder, topside or legs. Referring to food exchange list in Krause’s (3), meat and meat substitutes are considered as lean and high-fat if they contain <3g and >7g fat/oz respectively. For those with fat value in between, they are classified as medium-fat. Moreover, we usually used the unit “oz” to quantify meat, so I used 30g as the serve size because it is equivalent to 1 oz.
Lean and Medium Fat Meats
Kangeroo rump are found to be the most protein-rich, but least fat. Fat values of chicken drumstick and thigh vary with the presence of skin. Seldom carbohydrate can be found in meat, except for those being processed like sausage and luncheon meat. In addition, energy profile of eggs and seafood are lower than average.
High Fat Meats
Pork belly has the most contrasting fat and protein values with 16.7g and 2.7g/serve respectively. All but Parmesan cheese have higher fat than protein values within the food group.
Milk
I was in dilemma while I was deciding its serve size because I think there may not be a common serve size for milk. People usually consume milk together with coffee or tea according to personal favor. Someone may add a lot more than the others, so it is highly individualize. At last, I followed the serve size on ADG, 250ml (1 cup) for my reckoner (2).
Regarding to the definition of Food Standard Australia and New Zealand, skim milk should not contain more 0.15% of fat, which is <3g/serve (4). Milk is categorized as regular if it contains 3.5% of fat (~8g/serve). Meanwhile, fat percentage in between is regarded as medium fat. Soy, rice and almond are also included as they are common beverages. It is noted that they have either similar energy value or fat value to regular milk.
Fats and sugar
Fats and sugar are always suggested to consume in a small amount, so I would like to count them with a size of teaspoon, 5g. They are less variation in their macronutrient compositions within each food group. In spite of “healthy” fat in nuts, I put them in my table because they are commonly eaten and excessive intake may also lead to overweight.
Alcohol
One standard drink, 10g alcohol, is the serve size, due to variation in alcohol percentage in a fixed volume. Beer is the only kind of drink contains protein with 1.1g/standard drink.
(c1) Advantages of using a ready reckoner system
1. Ready reckoner allows quick and simple calculation on energy value of a diet. We can make use of the average value of each food group to calculate one’s diet by simply multiplying the number of serves they had. Comparing to counting the actual energy value of each food, ready reckoner may facilitate the diet analysis.
2. Ready reckoner gives an average for each macronutrient in different food groups. Other than estimating the total energy intake, intake portion of each macronutrient can be calculated. We can compare the results with ADG to see whether their diet pattern attains the recommendation.
3. It would be a useful tool in nutrition education as macronutrient values has been broken down within each food group. People are able to learn about the composition of a specific food group, thus, making better decision during grocery shopping.
4. Analysis can be done everywhere with ready reckoner. In contrast to computerized method, no electronic gadget is needed for analysis. Reckoner, as light and simple as a paper, can be brought along and used without limitation.
(c2) Disadvantages of using a ready reckoner system
1. Values in ready reckoner are just the averages of food groups. There may be error if someone took a food which has a value below or above the average. The energy value of Banana, for example, doubles the average, resulting overestimation on the total energy intake. This may not be a minor effect if such kind of food item frequently appears on one’s diet.
2. The user of ready reckoner should be experienced in cooking or familiar with food, so as to appropriately fit various kinds of food into corresponding food group and make an estimation. It is believed that not everyone is able to categorize the food correctly, particularly in terms of determining fat content in meat. Therefore, this type of reckoner may not be suitable for people who has low exposure to food.
3. The reckoner is probably effective only on a specific population. It is impossible to take all kinds of food into account while making the reference table, as such, the reckoner was mainly built on Australian culture. It will not be representative if it is used to analysis an Asian diet. Hence, it has low generalizability.
4. The interpreter should have an idea on how different cuisines are being cooked, otherwise there will be wrong estimation on how many sugars or oil has been added, affecting the final analysis. This would be challenging for interpreter to analysis a diet of someone who has a distinct cultural background as their own.