Glycemic Index of Plant Based Foods

The glycemic index (GI) is a measure of how quickly a food raises blood glucose levels after eating. It ranks foods on a scale from 0–100: Low GI (≤55) causes a slower, more gradual rise in blood sugar; Medium GI (56–69) causes a moderate rise; High GI (≥70) causes a rapid spike. Lower GI foods are generally better for blood sugar management and may help reduce the risk of type 2 diabetes and cardiovascular disease.

GI (Glycemic Index) measures how quickly a food raises blood sugar; GL (Glycemic Load) accounts for both the quality and quantity of carbohydrates in a typical serving. A food can have a high GI but a low GL if the serving size is small or carbs are minimal. GL = (GI × grams of carbs per serving) ÷ 100. GL is often more practical for daily eating decisions because it reflects realistic portion sizes.

The GI of oats varies significantly by processing. Steel-cut oats have a GI of around 42, rolled (old-fashioned) oats around 55, and instant oats can be as high as 65–80. Less processed oats retain more fibre structure, which slows digestion and lowers GI. Preparing oats with plant milk, adding nuts or seeds, and not overcooking helps keep the glycemic response lower.

Yes. Cooking generally increases a food's GI value. Longer cooking times soften fibre and increase the surface area available for digestion, causing faster glucose absorption. For example, overcooked pasta has a higher GI than al dente pasta. Whole grains and legumes retain more structure and lower GI when cooked until just tender rather than very soft. Cooling cooked starches (like cooled rice) also reduces GI slightly due to increased resistant starch formation.

Yes — white rice has a high GI (typically 64–72), while brown rice is lower (GI ~50–55). However, GI is only part of the picture. The portion size, what else you eat with the rice (beans, vegetables, fats), and the degree of cooking all affect actual blood sugar impact. Adding lentils or legumes to a rice meal significantly lowers the combined glycemic response.

Bananas have a medium GI (approximately 48–56 depending on ripeness). Underripe (green) bananas have a lower GI because their starch is less broken down; as bananas ripen, the starch converts to simpler sugars and the GI rises. Despite being moderate GI, bananas provide fibre, potassium, and resistant starch, and their glycemic load per typical serving is moderate.