Posts Tagged ‘glycemic index’
Wheat, paddy and most millets have comparable glycemic index. i.e. the total quantity of sugar released in ones blood on eating 100gms of the grain, a direct function of carbohydrate content. Looking at the nutrition chart we can see that the carbohydrate content in all these grains are not too different.
As I had written about earlier in the year, one needs to eat a lesser quantity of millets to feel as full as one would after eating another cereal grain such as polished paddy rice. So the serving size of millet based dishes are smaller and hence the glycemic load is lesser compared to preparations of polished paddy rice or refined flour.
And then there is the whole slow release aspect I had written about and identified how the carbohydrate to fibre ratio is a better indicator of this feature.
To sum up, after eating a millet based meal, the total sugar released into ones blood stream is reduced and the rate of increase initially, and the decrease later, in the blood sugar levels happens at a much more gradual rate when compared what is experienced after eating a meal of polished paddy rice or refined wheat flour.
Both these aspects are very beneficial for those with type 2 diabetes. Please note that diversity is almost always a good thing. It is advisable to include the various millets available in the local markets, unpolished/semi polished paddy rice and whole wheat flour to one’s diet.
Glycemic Index is a measure of how much the blood sugar (i.e. glucose) increases after one eats a certain food. Pure glucose has a GI of 100 and all other foods are ranked with reference to this. GI is a relative ranking of different foods and is useful in estimating how much sugar will the body have to deal with. There are a lot of junk articles online about GI, it is always a good idea to go to the research programs rather than use popular media sources for information. For example, the University of Sydney’s website on GI is a good source of information on GI.
Glycemic Load is another number that factors in the recommended serving size. It is calculated by multiplying the GI with the recommended serving size. So it gives a much more realistic representation of how much increase in blood sugar one can expect after eating a certain food item. A high GI food item eaten in a small quantity would not increase the blood sugar level too much, whereas, a medium GI food eaten in large quantities during a meal would dump a whole lot more sugar than one would like.
Now one thing that neither of these two numbers capture is how soon the carbohydrates from the food reach the blood and increase blood sugar levels.
If one plots the blood sugar levels measured in an individual after eating a meal, it will increase up to a certain level and then begin to drop. GI is the area under the curve. Anyone who has studied college math (and remembers it!) will immediately recognize that the area can be the same for two curves with very different rate of rise, or even different peak values. When we are trying to identify how our body is stressed during digestion and absorption of nutrients, the rate of change in blood sugar levels is a critical parameter.
And surprisingly, there is a simple number one can use to get a measure of this – the carbohydrates to fibre ratio. For convenience, lets call it the ‘C/F’ of a food. Digestive juices need to soften and move through the ingested fibre before they can get to the sugars. So a high fibre food item would have a slower release of sugars compared to the same item with low fibre content. Based on this idea, the Harvard School of Public Health has promoted the 10:1 thumb rule to assess if a food item is whole grain or not.
So lets see the comparative nutritional table for millets and do the math to calculate the C/F for each of the food items. And the resulting table is …
There are two main advantages of using C/F rather than GI when assessing how good a particular food item is.
- It can be identified with just a simple division operation that a consumer can do looking at the nutritional label and does not need lab testing and trials.
- It is a better reflection of how it affects a person concerned about diabetes and controlling blood sugar levels.
The primary nutrition we derive from our cereals is the energy from its carbohydrate content. But this needs to be moderated to decrease its rate of release into the blood stream. And this is achieved by having a good fibre content. The secondary nutritional components we derive are the minerals and essential fatty acids. Note that within a grain, carbohydrates are found in the endosperm, the inner (typically white) portion of the grain that forms a majority of its volume and mass. Fibre is mostly found in the bran, a thin protective layer around the grain also rich in minerals, essential fatty acids.
So looking at it beyond the labels and nutritional analysis, it is a fairly simple thing to remember when shopping for something to eat:
Has bran? Good
No bran? Naaa!
I do advocate for people to move to whole grains, not just in millets, but also with paddy rice and wheat. And at the same time I recognize that as with everything else in life, one has to compromise when negotiating what food to eat. So if eating polished/semi polished millets will get your family to accept it. Do make the shift. Gradually shift towards products that still have the bran layer.