GI part 1 – What is glycemic index

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๐Ÿ“š GI Series ยท Part 1 of 3

This is the first article in HealthBanyan’s Glycemic Index Complete Guide series.  |  Part 2: Low GI Fruits โ†’  |  Part 3: GI of Indian Foods โ†’

0โ€“100

The GI scale โ€” where 100 is pure glucose and lower numbers mean safer, slower blood sugar rise

55โ†“

GI of 55 or below = Low GI. Safest zone for diabetics and weight management

70+

High GI danger zone โ€” white bread, sugar, polished white rice cause rapid sugar spikes

38โ€“41

GI of parboiled rice โ€” one of the safest rice options for diabetics (see Rice vs Roti โ†’)

๐Ÿ“… Published: July 23, 2026  |  ๐Ÿฉบ Medically Reviewed: July 23, 2026  |  โฑ Reading time: 4 min

๐Ÿš You have been told to “avoid sugar” and “eat healthy.” But nobody told you that two bowls of white rice can spike your blood sugar just as badly as a spoonful of sugar โ€” even though they look nothing alike. That is the power of the Glycemic Index. And understanding it could change how you eat forever.

The Glycemic Index (GI) is the most underused tool in diabetes and weight management โ€” yet it is one of the most powerful. In this article, you will learn exactly what GI is, how to use the 0โ€“100 scale, and why it matters for you or someone you love with diabetes, prediabetes, or weight concerns.

เค—เฅเคฒเคฟเคธเคฎเคฟเค• เค‡เค‚เคกเฅ‡เค•เฅเคธ เคตเคน เคธเค‚เค–เฅเคฏเคพ เคนเฅˆ เคœเฅ‹ เค†เคชเค•เฅ‡ เค–เคพเคจเฅ‡ เค”เคฐ เค†เคชเค•เฅ€ เคถเฅเค—เคฐ เค•เฅ‡ เคฌเฅ€เคš เค•เคพ เค…เคธเคฒเฅ€ เคฐเคฟเคถเฅเคคเคพ เคฌเคคเคพเคคเฅ€ เคนเฅˆเฅค

Core Concept ยท เคฎเฅ‚เคฒ เค…เคตเคงเคพเคฐเคฃเคพ

What Is Glycemic Index (GI)? โ€” The Simple Explanation

เค—เฅเคฒเคฟเคธเคฎเคฟเค• เค‡เค‚เคกเฅ‡เค•เฅเคธ เค•เฅเคฏเคพ เคนเฅˆ โ€” เคธเคฐเคฒ เคญเคพเคทเคพ เคฎเฅ‡เค‚

The Glycemic Index (GI) is a numerical ranking system, from 0 to 100, that measures how quickly a carbohydrate-containing food raises blood glucose (sugar) levels after eating. It compares each food’s effect to pure glucose, which is assigned a GI of 100 โ€” the maximum possible spike.

Think of GI as a speed dial for sugar release. High-GI foods dump glucose into your bloodstream rapidly, causing spikes. Low-GI foods release glucose gradually, like a slow drip โ€” giving your body time to manage it properly through insulin.

70+

High GI ๐Ÿ”ด

White bread, white rice, sugar, cornflakes, watermelon, potato

Fast sugar spike โ€” avoid or limit

56โ€“69

Medium GI ๐ŸŸก

Basmati rice, whole wheat bread, banana, papaya, mango

Moderate โ€” portion control essential

55โ†“

Low GI ๐ŸŸข

Lentils (dal), rajma, brown rice, oats, apples, pears

Safest โ€” slow, steady sugar release

๐Ÿ”‘ GI was developed at the University of Toronto in 1981 by Dr David Jenkins โ€” it has since been tested on thousands of foods worldwide and forms the basis of diabetic dietary guidelines in over 40 countries.

GI 1981 เคฎเฅ‡เค‚ เคตเคฟเค•เคธเคฟเคค เคนเฅเค† เค”เคฐ เค†เคœ เคฆเฅเคจเคฟเคฏเคพ เคญเคฐ เคฎเฅ‡เค‚ เคกเคพเคฏเคฌเคฟเคŸเฅ€เคœ เค†เคนเคพเคฐ เค—เคพเค‡เคก เค•เคพ เค†เคงเคพเคฐ เคนเฅˆเฅค

Real Story ยท เค…เคธเคฒเฅ€ เค•เคนเคพเคจเฅ€

“I Was Eating ‘Healthy’ Brown Bread โ€” But My Sugar Was Still High.” โ€” Sunita’s Story

“เคฎเฅˆเค‚ ‘เคธเฅเคตเคธเฅเคฅ’ เคฌเฅเคฐเคพเค‰เคจ เคฌเฅเคฐเฅ‡เคก เค–เคพ เคฐเคนเฅ€ เคฅเฅ€ โ€” เคซเคฟเคฐ เคญเฅ€ เคถเฅเค—เคฐ เคฌเคขเคผเฅ€ เคฐเคนเฅ€เฅค”

1 The Confusion

Sunita, 44, a bank officer from Bhopal, was newly diagnosed with Type 2 diabetes. She switched immediately to what she believed were “healthy” choices: brown bread toast for breakfast, fruit juice for vitamins, and white rice replaced with slightly less white rice. Her blood sugar readings remained stubbornly high at every check.

2 The GI Explanation

Her dietitian introduced her to GI. Most commercial brown bread is GI 65โ€“70 โ€” barely different from white bread. Fruit juice concentrates sugar from multiple fruits, removing fibre, giving it a GI of 55โ€“65. The “slightly less” white rice was still GI 72. Sunita had changed the appearance of her diet without changing its glycaemic impact.

3 The Switch That Worked

Sunita switched to parboiled rice (GI 38โ€“41) instead of white rice, whole oats instead of brown bread, and whole fruit instead of juice. Within eight weeks her post-meal blood sugar had dropped by an average of 38 mg/dL without any medication change. Name changed. Scenario is illustrative.

๐Ÿ’ก Lesson

Foods that look healthy can have the same GI as junk food. “Brown” or “natural” labels mean nothing without checking the GI. The number matters โ€” not the colour.

GI Reference Table ยท เคธเค‚เคฆเคฐเฅเคญ เคคเคพเคฒเคฟเค•เคพ

๐Ÿ“Š GI of Common Indian Foods โ€” at a Glance

เคธเคพเคฎเคพเคจเฅเคฏ เคญเคพเคฐเคคเฅ€เคฏ เค–เคพเคจเฅ‡ เค•เคพ GI โ€” เคเค• เคจเคœเคผเคฐ เคฎเฅ‡เค‚

Food GI Category Advice for Diabetics
Moong dal (yellow) 38 ๐ŸŸข Low Excellent โ€” eat daily
Oats (plain, rolled) 55 ๐ŸŸข Low Good breakfast choice
Parboiled rice (sela/ukda) 38โ€“41 ๐ŸŸข Low Best rice choice for diabetics
Whole wheat roti (thin) 49โ€“55 ๐ŸŸก Low-Med Acceptable โ€” 1โ€“2 per meal
Basmati rice (cooked) 50โ€“58 ๐ŸŸก Medium Smaller portions only
White bread / maida roti 71โ€“75 ๐Ÿ”ด High Avoid โ€” spikes blood sugar fast
White polished rice 72 ๐Ÿ”ด High Replace with parboiled rice
Poha (beaten rice) 70โ€“75 ๐Ÿ”ด High Limit โ€” add peanuts + vegetables to lower impact
Sugar / glucose 65โ€“100 ๐Ÿ”ด Very High Use only for treating hypoglycaemia
Why It Matters ยท เค•เฅเคฏเฅ‹เค‚ เคœเคผเคฐเฅ‚เคฐเฅ€ เคนเฅˆ

Why Glycemic Index Changes the Game for Diabetics

เคกเคพเคฏเคฌเคฟเคŸเฅ€เคœ เคฎเฅ‡เค‚ GI เค•เฅเคฏเฅ‹เค‚ เค‡เคคเคจเคพ เคฎเคนเคคเฅเคตเคชเฅ‚เคฐเฅเคฃ เคนเฅˆ

๐Ÿฉธ

Blood Sugar Control

Low GI foods maintain stable blood sugar between meals โ€” reducing dangerous spikes and the need for insulin correction. Essential for every diabetic managing their medication correctly.

โš–๏ธ

Weight Management

High GI foods cause rapid spikes followed by crashes โ€” triggering hunger within hours. Low GI foods keep you full longer, reducing total caloric intake naturally.

โค๏ธ

Heart Protection

Lower GI diets are associated with reduced LDL cholesterol, lower triglycerides, and better arterial function โ€” particularly important for diabetics with elevated cardiac risk.

Myths vs Facts ยท เคฎเคฟเคฅเฅเคฏเคพ vs เคธเคšเฅเคšเคพเคˆ

4 Common Myths About Glycemic Index โ€” Busted

GI เค•เฅ‡ เคฌเคพเคฐเฅ‡ เคฎเฅ‡เค‚ 4 เค†เคฎ เคฎเคฟเคฅเฅเคฏเคพ

โŒ Myth 1: “If a food is natural, it has a low GI”
โœ… FACT: Watermelon is natural โ€” GI 72. White sugar is 65. “Natural” means nothing about GI. Only the actual number counts, which is why checking a GI chart is essential.
โŒ Myth 2: “Brown bread is always low GI”
โœ… FACT: Most commercial brown bread in India contains refined flour with added colour and has a GI of 65โ€“70 โ€” almost identical to white bread. True low-GI breads use stone-ground whole grain flour and have visible grain texture.
โŒ Myth 3: “Low GI means I can eat as much as I want”
โœ… FACT: GI measures speed of sugar release, not total sugar content. Eating a very large portion of a low-GI food still raises blood sugar significantly โ€” which is where Glycaemic Load (GI ร— portion size) comes in. See our Rice vs Roti article for how this applies practically.
โŒ Myth 4: “GI only matters for diabetics”
โœ… FACT: GI is equally relevant for weight management, cardiovascular health, energy levels, and reducing the risk of developing early-onset diabetes in young adults. Every person who eats carbohydrates benefits from understanding GI.
FAQs ยท เค…เค•เฅเคธเคฐ เคชเฅ‚เค›เฅ‡ เคœเคพเคจเฅ‡ เคตเคพเคฒเฅ‡ เคธเคตเคพเคฒ

Frequently Asked Questions โ€” Glycemic Index

Q: Does cooking method affect glycemic index?

Yes significantly. Overcooking increases GI โ€” overcooked rice has a higher GI than al dente rice. Cooling cooked rice for 12โ€“24 hours converts starch to resistant starch, reducing effective GI by up to 35%. Learn more in our Rice vs Roti guide โ†’

Q: Can I mix high and low GI foods to lower the overall GI of a meal?

Yes โ€” this is one of the most practical applications of GI. Adding dal, protein (curd, egg, paneer), or fibre-rich vegetables to a rice meal significantly lowers the meal’s overall glycaemic impact. This is why sambar rice has a lower blood sugar effect than plain white rice alone.

Q: What is the GI of jaggery (gur) โ€” is it better than sugar for diabetics?

Jaggery has a GI of approximately 84 โ€” actually higher than white table sugar (GI 65). Despite its traditional and mineral-rich reputation, jaggery raises blood sugar faster than regular sugar and is not a safe alternative for diabetics in significant amounts.

“The Glycemic Index is the single most practical dietary tool I recommend to every diabetic patient โ€” yet it is almost never explained at the time of diagnosis. Understanding it takes 10 minutes. Applying it consistently changes blood sugar control within weeks.”

“GI เคธเคฎเคเคจเคพ 10 เคฎเคฟเคจเคŸ เค•เคพ เค•เคพเคฎ เคนเฅˆ โ€” เค”เคฐ เคนเคซเฅเคคเฅ‹เค‚ เคฎเฅ‡เค‚ เคถเฅเค—เคฐ เคฌเคฆเคฒ เคฆเฅ‡เคคเคพ เคนเฅˆเฅค”

โœ๏ธ Written By

Dr Nirmala Singh

Expert Clinician & Senior Paediatrician
Medical Writer, HealthBanyan

๐Ÿฉบ Reviewed By

HealthBanyan Medical Research Team

Evidence-Based Clinical Review
HealthBanyan

References

1. Jenkins DJ, et al. Glycemic index of foods: a physiological basis. American Journal of Clinical Nutrition. 1981.

2. Atkinson FS, Foster-Powell K, Brand-Miller JC. International tables of GI and glycaemic load values. Diabetes Care. 2008;31(12).

3. ICMR-NIN. Dietary Guidelines for Indians. National Institute of Nutrition, Hyderabad. 2024.

๐Ÿ“š GI Series ยท Coming Up Next โ€” Part 2 of 3

You know what GI is โ€” but can you name the fruit that’s “healthy” but secretly spikes blood sugar in diabetics?

Part 2 reveals which fruits are truly safe for diabetics, which ones fool you with their “natural” label, and the 8 low-GI fruits perfect for Indian diabetics with full data, myths, and a regional guide.

๐ŸŽ Read Part 2: Low GI Fruits for Diabetics โ†’

Medical Disclaimer: This article is for educational purposes only. Consult your diabetologist or registered dietitian for a personalised meal plan based on your specific condition and medications.

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