Okay, confession: I built this chart because I got tired of standing in the cereal aisle at Trader Joe's, phone out, squinting at three different nutrition apps that each gave me a different number for the same box of cornflakes. Somebody needed to just write the real numbers down in one place — from actual sources, not vibes — so I did.
Here's the thing about the glycemic index once you're the one living with it: it stops being a diabetes-textbook concept and turns into something closer to a budget. You get a certain number of GI "points" you can spend on a meal before your continuous glucose monitor starts chirping at you like an angry smoke detector, and you learn fast which foods are a splurge and which ones are basically free. Watermelon, it turns out, is a splurge — I found that out the hard way at a Fourth of July barbecue and spent the rest of the afternoon wondering why I felt like I'd been hit by a bus.
I also want to save you a wasted grocery run: the "healthy" instant oatmeal packets with the green leaf on the box? Higher GI than a lot of desserts. Learned that one the expensive way — bought a whole case at Costco before I knew better, and half of it is still sitting in my pantry because I can't bring myself to eat it anymore.
This isn't a substitute for a lab test or a real conversation with your own doctor or dietitian — it's the cheat sheet I wish someone had handed me the day I got my results back, so I'm handing it to you instead.
Glycemic Index Range Definitions
Before you dive into the table, here's the shorthand I use to sort foods fast — low, medium, high. According to the University of Sydney's Glycemic Index Research FAQ and Harvard T.H. Chan's Nutrition Source, the ranges break down like this:
- Low GI (55 or less)
- Foods that are digested and absorbed slowly, resulting in a gradual rise in blood sugar.
- Medium GI (56 to 69)
- Foods that produce a moderate rise in blood sugar levels.
- High GI (70 or more)
- Foods that are rapidly digested and absorbed, causing a quick spike in blood sugar.
Glycemic Index Reference Table
This is the actual chart — the one taped inside my pantry door, coffee stain and all. The numbers come straight from the international glycemic index and glycemic load dataset published in Diabetes Care, reported as the mean GI value across study subjects (± standard error, glucose = 100). I didn't round these to make them prettier; if the source says 81 ± 6, that's what's on the label under the cornflakes box that got "donated" to my neighbor and never came back.
| Food Item | GI Value (Mean ± SEM) | GI Category |
|---|---|---|
| Chickpeas | 28 ± 9 [1] | Low |
| Lentils | 32 ± 5 [1] | Low |
| Apple (raw) | 36 ± 2 [1] | Low |
| Skim Milk | 37 ± 4 [1] | Low |
| Spaghetti (white) | 49 ± 2 [1] | Low |
| Rolled Oats (porridge) | 55 ± 2 [1] | Low |
| Sweet Potato (boiled) | 63 ± 6 [1] | Medium |
| Brown Rice (boiled) | 68 ± 4 [1] | Medium |
| White Rice (boiled) | 73 ± 4 [1] | High |
| White Bread | 75 ± 2 [1] | High |
| Watermelon (raw) | 76 ± 4 [1] | High |
| Potato (boiled) | 78 ± 4 [1] | High |
| Cornflakes | 81 ± 6 [1] | High |
Factors Influencing Glycemic Index Values
The GI number on this chart isn't fixed — it moves depending on what you do to the food before it hits your plate, which took me embarrassingly long to figure out. According to Harvard's Nutrition Source and the University of Sydney's own FAQ, here's what actually moves the needle:
- Ripeness: The riper the fruit, the higher the GI — annoying news for anyone (me) who prefers bananas with brown spots.
- Processing: Milled and refined grains score higher than minimally processed ones — basically the difference between steel-cut oats and the instant packets still sitting sadly in my pantry.
- Cooking Method: Overcooking raises GI. Pasta is supposed to stay al dente — firm enough to fight back a little when you chew it, not the mushy stuff I served my in-laws that one Thanksgiving.
- Food Combinations: Pairing carbs with fiber, fat, or protein slows digestion and lowers the overall glycemic response of the meal.
- Acid Content: A splash of vinegar, lemon, or lime juice slows how fast your stomach empties, which lowers the GI of the whole plate — my one legitimate excuse for drowning everything in vinaigrette.
One honest disclaimer, in case it isn't obvious: I'm not a doctor, a dietitian, or anything with letters after my name — I'm an HR manager who got a bad lab result and went down a research rabbit hole. Everything on this chart is pulled from real published sources, but your body isn't a spreadsheet, and neither is mine. If you're on insulin or a sulfonylurea (glipizide, glyburide, that family), please loop in your doctor or pharmacist before you overhaul how you eat — dropping your glycemic load fast while your medication is still dosed for your old diet is a real way to end up with dangerously low blood sugar, not a hypothetical one. Talk to your own doctor about what any of this means for you. This chart is a reference, not a prescription.
Last verified: 2026-07-11
Sources
- Atkinson FS, Foster-Powell K, Brand-Miller JC. International tables of glycemic index and glycemic load values: 2008. Diabetes Care. 2008;31(12):2281-2283.
- University of Sydney: Glycemic Index Research and GI News — FAQs
- Harvard T.H. Chan School of Public Health: The Nutrition Source — Carbohydrates and Blood Sugar