Indian diets are quite carb heavy. But we need to understand that not all carbohydrates react the same. Certain kinds tend to cause rapid blood sugar spikes, while other can still be gentle. There are 2 important concepts: glycemic index and glycemic load. This article talks about these concepts in depth and get an understanding of why they should matter
What is glycemic index or GI?
Glycemic index is a ranking of foods that are made up of carbohydrates on a scale of 1 to 100 how they raise blood glucose levels. This measure is compared with a reference, usually pure glucose or white bread. If you talk about glycemic index of sugar, sucrose has a moderately high GI because it gets rapidly absorbed and digested
If you talk about the GI of sugar, sucrose has a moderately high GO because it rapidly gets digested and absorbed into your body. Studies have listed white sugar with a GI around 65
Why is GI useful? It helps predict how quick can a particular food raise your blood glucose, which is a key concern for diabetics, to manage their energy and control weight
What is glycemic load or GL?
Glycemic load combines the quality and quantity of a carbohydrate in a serving. In simple terms, its GI, but factoring in size or portion of the carbs you’re eating. This is the formula for calculating GL, take notes
{GL = GI x grams of carbohydrates / 100}
Even foods with high GI can produce low GL if the portion of carbohydrates is lesser, against a lower GI food which can give a higher GL if the portions are large.
Why should you care about GL? Because it shows the real effects of food on your blood glucose better than just GI alone. And in the classic case of glycemic index V glycemic load, GL often provides more actionable guidance.
Glycemic Index vs Glycemic Load: the show down
Let's do a side-by-side comparison:
- GI – looks at how fast and how much a fixed amount of a test food raises your blood sugar. The scores are relative.
- GL – looks at how much carbs are you really eating and how fast would that raise your glucose. It gives an absolute estimate of blood sugar impact for realistic portions.
- While GI ignores portion size, GL accounts for it.
- Foods with high GI may nevertheless have a modest GL if you eat smaller servings, thus someone focusing solely on the GI could misjudge the actual effect. For planning meals, GL tends to reflect a cumulative impact of foods in a meal. (1)
- If you focus only on Low GI but eat large portions of it, you will still see large glucose spikes, and GL helps guard against that.
How to calculate glycemic index and glycemic load
A test subject takes a portion of the food containing a fixed amount of available carbohydrate (usually 50g). After that, their blood glucose levels are measured over a 2-hour period, the incremental area under the blood glucose response curve (IAUC) is computed.
Then the subject ingests the reference food in another session and the IAUC is computed.
Then the formula becomes GI = (IAUC test ÷ IAUC reference) x 100
How to calculate glycemic load for a specific serving
Formula: (GI x the grams of carbs in the serving) ÷ 100
For eg: if your food has a GI of 70, and you are eating a serving with 30g of carbs, then,
GL = (70 x 30) ÷ 100 = 21
Which is considered high as per Indian standard.
Research and data
There are multiple studies regarding behavioural patterns of GI and GL when it comes to Indian food. They have found GI values that range from ~36.9 in sambar vada, to ~79.9 in an onion dosa, with GL values ranging from ~18.4 to ~39.7 basis on their portion size.
Some simpler examples:
Another study found wheat - based meals and rice – based meals have a similar GI, when the carbs in them are the same. Furthermore, a study saw that when we add fenugreek (methi) seed flakes in dishes that we usually add in our dishes. A study was conducted which found that adding fenugreek (methi) seed flakes to your food can help improve GI / GL behaviour.
Why it matters for health:
High GI / GL diets raise your blood glucose and insulin sharply, which is called post prandial hyperglycaemia. Over time this cause insulin resistance, type 2 diabetes and put you under cardiovascular risks. Authorities have already started posting concerns about the sharp insulin spikes. It is advised that both diabetics and pre diabetics follow a planned GI vs GL based meal plan, so that their glucose is in check.
For others, eating a lower GI meal helps you avoid large blood sugar swings, improves energy stability and helps in weight management. Since a traditional Indian diet considers carb-based items as staples, the composition of your meal, serving size, adding fibre into the mix, matters the most.
Practical tips for using GI and GL in Indian meals
- Refer to Indian GI charts for staples like, white rice vs brown rice and dosa vs idli, to identify high GI items.
- Monitor serving size, even if the food your eating has a lower GI, eating them in larger portions can increase GL and hence impact your blood glucose levels.
- Mix things up a bit. Eat a combination of high GI foods with low GI/GL foods.
- Adding legumes, fibre or vegetables to your meals helps lower the GI/GL levels.
- If it is possible, try to avoid eating white rice, white bread, sugary snacks in larger quantities or portions because they have one of the highest GI and can contribute to a higher GL.
- Stay consistent with your meals/diet. Study about the GI of your foods, calculate your GL and then aim for meals with a moderate GL. Foods with GL lesser than ~20 is considered safer.
And that’s the bottom line:
- Glycemic index determines how fast can a carbohydrate based food increase your blood glucose levels.
- Glycemic load determines how much that food will raise your blood glucose considering the portion size.
- In the case of glycemic index vs glycemic load, GL always wins because it combines GI + serving size.
- For managing blood sugar levels, especially when our staples are carbohydrate heavy, mix low GI/GL foods with your meals to balance it out.
FAQs:
1. Does the way you cook affect your foods glycemic index?
Yes. Cooking increases availability of starch for digestion, which increases your glycemic index. Boiled potatoes have a GI that’s higher than that of baked potatoes. When you put your rice or pasta to cool down before you eat it increases starch resistance, which lowers the effective GI.
2. Does combining foods affect their glycemic impact?
Yes. Pairing carbs with some protein, fat, and fibre slows down the absorption of glucose. A classic dal with white rice, and some kind of vegetable or curd lowers the meal’s overall glycemic load.
3. Does glycemic index only apply for diabetics?
No. It is vital for managing diabetes, GI and GL are essential for stable energy levels, overall satiety, or weight control, which everyone should be mindful about.
4. Does glycemic index vary from person to person?
Yes. An individual's responses to carbohydrates differ on the basis of gut microbiota, metabolism, insulin sensitivity, and how activity they are. Meaning, even though a food’s GI levels are low, it may not reach the same in everyone’s body.
5. Are low-GI foods healthier?
Low GI does not automatically make a food healthy. Ice creams have a lower GI due to it fat content, but it is quite high in sugar and calories. GI and GL should be considered alongside overall nutritional quality.