Low Glycemic Grains: Complete Guide (2025)
Quick Answer:
The best low GI grains are barley (GI 28), bulgur wheat (48), quinoa (53), steel-cut oats (52), and whole wheat pasta (48). These provide sustained energy without blood sugar spikes. Avoid refined grains like white rice and white bread.
Grains are a staple in most diets, but choosing the right ones makes all the difference for blood sugar control. While refined grains cause rapid spikes, low glycemic whole grains provide steady energy, better satiety, and numerous health benefits.
This guide covers 25 common grains ranked by glycemic index, explains why some grains are better than others, and provides practical tips for incorporating them into your meals.
Table of Contents
Complete Grain GI Ranking
Here are 25 common grains and grain products ranked from lowest to highest glycemic index:
| Grain/Product | GI Value | Category | Serving Size | GL |
|---|---|---|---|---|
| Barley | 28 | Low | 150g | 8 |
| All-Bran | 42 | Low | 30g | 6 |
| Spaghetti, whole wheat | 48 | Low | 180g | 18 |
| Bulgur Wheat | 48 | Low | 150g | 12 |
| Spaghetti, white | 49 | Low | 180g | 20 |
| Muesli | 49 | Low | 30g | 8 |
| Pumpernickel Bread | 50 | Low | 30g | 7 |
| Steel-cut Oats | 52 | Low | 250g | 11 |
| Quinoa, cooked | 53 | Low | 150g | 16 |
| Sourdough Bread | 54 | Low | 30g | 8 |
| Oats, rolled | 55 | Low | 250g | 12 |
| Wild Rice | 57 | Medium | 150g | 18 |
| Rye Bread | 58 | Medium | 30g | 8 |
| Basmati Rice, white | 58 | Medium | 150g | 22 |
| Couscous | 65 | Medium | 150g | 23 |
| Brown Rice, steamed | 68 | Medium | 150g | 22 |
| Bagel, white | 72 | High | 70g | 25 |
| White Rice | 73 | High | 150g | 26 |
| Whole Wheat Bread | 74 | High | 30g | 9 |
| Bran Flakes | 74 | High | 30g | 13 |
| White Bread | 75 | High | 30g | 11 |
| Shredded Wheat | 75 | High | 30g | 15 |
| Oatmeal, instant | 79 | High | 250g | 17 |
| Cornflakes | 81 | High | 30g | 21 |
| Jasmine Rice | 89 | High | 150g | 37 |
Top 5 Low GI Grains (Detailed Guide)
1. Barley - GI: 28
Winner: Lowest GI Grain
Barley is the champion of low GI grains. Its high beta-glucan fiber content slows digestion dramatically, resulting in the lowest GI of any common grain.
Benefits:
- Reduces cholesterol by 5-10%
- Extremely filling, aids weight loss
- Improves insulin sensitivity
- Rich in vitamins and minerals
How to Use:
- Swap for rice in any dish
- Add to soups and stews
- Use in grain salads
- Make barley risotto
2. Bulgur Wheat - GI: 48
Bulgur is parboiled cracked wheat that cooks quickly while maintaining a low GI. Popular in Middle Eastern cuisine (think tabbouleh).
Benefits:
- Cooks in just 10-12 minutes
- High in fiber and protein
- Nutty, satisfying texture
How to Use:
- Tabbouleh salad
- Pilaf-style side dishes
- Breakfast porridge
3. Steel-Cut Oats - GI: 52
Steel-cut oats are minimally processed oat groats that retain more fiber and nutrients than rolled or instant oats, resulting in a lower GI.
Benefits:
- Keeps you full for hours
- Heart-healthy beta-glucan
- Provides sustained energy
How to Use:
- Overnight oats (cold soak)
- Savory oat bowls
- Traditional porridge
4. Quinoa - GI: 53
Technically a seed, quinoa is used like a grain. It's a complete protein with all 9 essential amino acids—rare for plant foods.
Benefits:
- Complete protein (8g per cup)
- Gluten-free
- High in iron and magnesium
How to Use:
- Buddha bowls
- Salad base
- Rice substitute
5. Whole Wheat Pasta - GI: 48
Good news for pasta lovers! Whole wheat pasta cooked al dente has a surprisingly low GI due to its protein and fiber content, plus the compact starch structure.
Benefits:
- Higher fiber than white pasta
- Familiar and satisfying
- Easy to portion control
Pro Tip:
Cook al dente (firm to bite). Overcooking breaks down starches and raises GI. Pair with protein and vegetables for balanced meal.
Why Whole Grains Have Lower GI
Understanding what makes a grain "whole" explains why it has a lower glycemic impact:
Bran (Outer Layer)
Contains fiber, B vitamins, antioxidants. This fiber slows digestion dramatically.
Germ (Core)
Packed with healthy fats, protein, vitamins E & B, minerals. Provides sustained energy.
Endosperm (Middle)
Contains carbs and some protein. Refined grains keep only this part, losing nutrients and fiber.
The Refining Problem:
When grains are refined (white flour, white rice), they remove the bran and germ, leaving only the starchy endosperm. This:
- Removes 75% of the fiber
- Removes most vitamins and minerals
- Creates a food that digests rapidly, spiking blood sugar
- Increases GI by 20-50 points compared to whole grain version
High GI Grains to Limit
These refined grains have high GI values and should be consumed sparingly:
| Grain Product | GI | Problem | Better Substitute |
|---|---|---|---|
| Jasmine Rice | 89 | Very high, rapid spike | Basmati or Barley |
| Cornflakes | 81 | Breakfast spike | Steel-cut Oats |
| Instant Oatmeal | 79 | Overprocessed | Steel-cut Oats |
| White Bread | 75 | No fiber, rapid digestion | Sourdough |
| Shredded Wheat | 75 | Despite being "whole grain" | Muesli or All-Bran |
| Whole Wheat Bread | 74 | Finely ground flour | Sourdough or Pumpernickel |
| Bran Flakes | 74 | Added sugar, processed | All-Bran or Muesli |
| White Rice | 73 | High GL per serving | Basmati Rice |
| Bagel (white) | 72 | Dense, refined flour | Sourdough toast |
Cooking & Preparation Tips
Lower GI Through Cooking Method
✓ Methods That Lower GI:
- Cook al dente (firm to bite)
- Cook and cool (creates resistant starch)
- Add vinegar or lemon to cooking water
- Soak grains overnight before cooking
✗ Methods That Raise GI:
- Overcooking until mushy
- Using instant or minute versions
- Grinding into fine flour
- Reheating multiple times
The Resistant Starch Trick
Pro tip: Cook rice, pasta, or grains, then refrigerate overnight. When you reheat, the GI is 20-30% lower than freshly cooked!
Why it works: Cooling allows starches to crystallize into "resistant starch" that behaves more like fiber, passing through your system without fully digesting.
Portion Control Guide
Low GI Grain Meal Ideas
Breakfast
- Steel-cut oats with berries, walnuts, cinnamon
- Overnight barley porridge with apple and almond butter
- Whole grain sourdough toast with avocado and eggs
- Savory quinoa bowl with vegetables and poached egg
Lunch
- Tabbouleh salad (bulgur wheat) with chickpeas
- Barley vegetable soup with crusty sourdough
- Quinoa buddha bowl with roasted vegetables and tahini
- Whole wheat pasta salad with grilled chicken and vegetables
Dinner
- Barley risotto with mushrooms and parmesan
- Whole wheat pasta with tomato sauce and lean meatballs
- Wild rice pilaf with grilled salmon and asparagus
- Quinoa-stuffed peppers with ground turkey
Frequently Asked Questions
What grains are low glycemic?
Low glycemic grains (GI below 55) include barley (28), bulgur wheat (48), quinoa (53), steel-cut oats (52), whole wheat pasta (48), and sourdough bread (54). These grains cause gradual blood sugar rises compared to refined grains.
Is rice a low GI grain?
Most rice is not low GI. White rice has GI 73, jasmine rice 89, and brown rice 68. However, basmati rice (GI 58) and wild rice (GI 57) are better choices with medium GI values. Cook and cool rice overnight to lower GI by 20-30%.
What is the lowest GI grain?
Barley has the lowest GI among common grains at 28. It's extremely high in soluble fiber (beta-glucan) which slows digestion and improves blood sugar control. Barley can be used anywhere you'd use rice.
Is whole wheat bread low GI?
Most whole wheat bread is NOT low GI (GI 74). Despite being "whole grain," it's made from finely ground flour that digests quickly. Sourdough bread (GI 54) and pumpernickel (GI 50) are much better choices due to their fermentation process and coarser grind.
Are rolled oats low GI?
Regular rolled oats have GI 55 (borderline low), while steel-cut oats have GI 52 (solidly low). Instant oatmeal has GI 79 (high) due to extra processing. Always choose steel-cut or rolled oats, never instant.
Can I eat pasta on a low GI diet?
Yes! Whole wheat pasta cooked al dente has GI 48 (low). The key is cooking it firm, not mushy, and watching portion sizes. Pair with protein and vegetables for a balanced low GI meal.
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Scientific References
- 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.
- Bjorck I, et al. Food properties affecting the digestion and absorption of carbohydrates. Am J Clin Nutr. 1994;59(3 Suppl):699S-705S.
- Brighenti F, et al. Effect of neutralized and native vinegar on blood glucose and acetate responses to a mixed meal in healthy subjects. Eur J Clin Nutr. 1995;49(4):242-247.
- Wolever TMS, et al. Beneficial effect of a low glycaemic index diet in type 2 diabetes. Diabet Med. 1992;9(5):451-458.