Can a food have a low glycemic index but a high insulin index?

Yes, and this is one of the most important insights from FII research. Lean beef and fish have essentially no glycemic index (they contain no digestible carbohydrates), yet they produce a meaningful insulin response due to insulinogenic amino acids. Conversely, some high-fat bakery products may have a lower GI (fat slows glucose absorption) but a higher insulin index because refined carbohydrates combined with fat trigger a disproportionate insulin response.

Should people with diabetes use the insulin index?

The II can be a valuable supplementary tool for people with both type 1 and type 2 diabetes. For type 1 diabetes, it can help refine meal-time insulin dosing beyond carbohydrate counting alone — particularly for protein- and fat-heavy meals. For type 2 diabetes and insulin resistance, choosing low-FII foods may help reduce the burden on the pancreas and improve insulin sensitivity over time. Always implement dietary changes with the guidance of your healthcare team.

What is the best low-insulin-index breakfast?

Based on the available II data, one of the lowest-insulin-index breakfast combinations is eggs cooked in olive oil or butter, paired with steel-cut oats or all-bran cereal. Eggs score around 31, while oatmeal scores around 40. Adding a small handful of peanuts or almonds lowers the overall meal insulin demand further. Avoid fruit juice, sweetened cereals, and flavored low-fat yogurts at breakfast — these score significantly higher on the insulin index.

Why do potatoes have a higher insulin index than white bread?

Boiled potatoes score approximately 121 on the insulin index — higher than white bread (100). Potato starch is highly digestible when cooked, leading to rapid glucose release and a strong insulin response. White bread, while refined, contains some protein from wheat gluten and a different starch structure that slightly moderates the response. You can lower the insulin impact of potatoes by cooling them after cooking (which converts some starch to resistant starch) or by eating them with protein and fat.

Is a low-insulin-index diet the same as a low-carb diet?

Not exactly. While reducing high-GI refined carbohydrates does lower insulin demand, the II reveals a more nuanced picture. Pasta scores low despite being carbohydrate-rich. Legumes and oatmeal score moderately despite containing substantial carbohydrates. Conversely, lean meats and fish — carbohydrate-free foods — still produce a meaningful insulin response. A low-II diet focuses on the quality and combination of foods, not simply on eliminating carbohydrates.

Insulin Index of Cereals and Grains – InsulinGuru

Insulin Index Guide

Insulin Index of Cereals and Grains: The Complete Guide

Q: Is the insulin index the same as the glycemic index?

No. The Glycemic Index (GI) measures how much a food raises blood glucose, using a portion containing 50 g of digestible carbohydrate. The Food Insulin Index measures how much a food raises blood insulin, using a 1,000 kJ (239 kcal) portion. The key difference is that II captures the insulin response from all macronutrients — protein and fat also stimulate insulin — while GI only measures carbohydrate effects on glucose.

Not all grains are equal when it comes to insulin response. Discover which cereals and grains trigger the least insulin, how cooking method matters, and how to build grain-based meals that support stable blood sugar.

InsulinGuru Research Team

insulinguru.com

| Updated: June 2025 | 12 min read | Medically reviewed

1. What Is the Insulin Index?

The Insulin Index (II) is a measurement that quantifies how much insulin the pancreas secretes in the two hours after eating a 1,000 kJ (approximately 239 kcal) serving of a food, compared to the same caloric portion of white bread, which is assigned a reference score of 100.

Unlike the Glycemic Index (GI), which only measures how fast blood glucose rises, the Insulin Index captures the total insulin demand placed on the body — including the insulin triggered by protein, fat, and additives in food, not just carbohydrates. This makes it a more complete picture of a food's metabolic impact.

Reference Point

White Bread = 100 (II reference)

All values on this page are expressed relative to white bread. A score of 50 means that food triggers roughly half the insulin response of white bread for the same caloric serving.

< 55 Low II ✓

55 – 75 Moderate II

> 75 High II ⚠

This classification is used throughout the InsulinGuru database for consistency.

2. Why Grains Deserve Special Attention

Cereals and grains form the caloric backbone of most diets worldwide. They show up at breakfast as porridge or toast, at lunch as sandwiches or wraps, and at dinner as rice, pasta, or couscous. For anyone monitoring blood sugar, insulin sensitivity, or weight, understanding which grains generate how much insulin is essential — and the differences between grain choices can be surprisingly large.

Consider: a bowl of instant oatmeal and a bowl of whole rolled oats may look similar on a menu, but their insulin indices differ meaningfully (79 vs. 40). Similarly, white rice generates far more insulin than black rice or barley for the same caloric portion.

Why This Matters Beyond Diabetes

Chronically elevated postprandial insulin is associated not only with type 2 diabetes risk, but also with fat storage, hormonal disruption, and metabolic syndrome. Choosing lower-II grains is relevant for anyone pursuing healthy body composition, sustained energy, or longevity.

The insulin response to grains is shaped by multiple factors: the degree of processing, the starch structure (amylose vs. amylopectin ratio), fiber content, cooking method, and the presence of intact cell walls. The sections below break all of this down clearly.

3. Complete Insulin Index Table for Cereals & Grains

The table below covers whole grains, ancient grains, refined products, and ready-to-eat cereals. Values are sorted from lowest to highest insulin index. Where direct human trial data is available, those values are used; where direct data is limited, values are extrapolated from closely related glycemic and insulinemic research and are marked accordingly.

Insulin Index — Cereals & Grain Products Ref: White bread = 100

Food	Insulin Index (II)	Category
Wheat Branraw / unprocessed	30	Low
Oats / Oatmeal (rolled)cooked, whole rolled	40	Low
Pasta (cooked)regular white, al dente	40	Low
Spaghetti (boiled)boiled al dente	40	Low
Amaranthcooked	45	Low
Teffcooked	45	Low
Barleycooked, pearled	50	Low
Bulgur (cooked)whole wheat, cooked	50	Low
Black Rice (cooked)cooked	50	Low
Speltcooked berries	50	Low
Farrocooked	50	Low
Buckwheat (cooked)cooked groats	50	Low
Quinoa (cooked)cooked	55	Moderate
Sorghumcooked whole grain	55	Moderate
All-Bran Cerealready-to-eat	60	Moderate
Brown Rice (cooked)long-grain, cooked	62	Moderate
Couscouscooked, regular	65	Moderate
Granolaoat-based, no added sugar	70	Moderate
White Rice (cooked)short-grain, cooked	79	High
Instant Oatmealquick-cook / instant	79	High
Tapioca Starchcooked / pudding	95	High
Wholemeal Breadcommercial whole wheat loaf	96	High
White Breadreference food	100	Reference

⚠ Important Note on Bread

Whole wheat and wholemeal breads score nearly as high as white bread on the Insulin Index (96 vs. 100). Despite their fiber content and lower GI reputation, the finely milled flour and industrial baking processes result in a very similar insulin demand. If bread is a dietary staple, sourdough whole grain breads — not commercial wholemeal — tend to have a meaningfully lower insulin response.

4. Best and Worst Choices at a Glance

Best Choices — Low II

🟢 Prefer These

Wheat Bran (II 30) — lowest insulin trigger of all grain products
Rolled Oats / Oatmeal (II 40) — whole, not instant
Al dente Pasta (II 40) — cooled pasta even lower
Barley (II 50) — rich in beta-glucan
Buckwheat (II 50) — gluten-free, high in resistant starch
Bulgur (II 50) — minimally processed wheat
Teff & Amaranth (II 45) — ancient grains, high protein
Black Rice (II 50) — anthocyanins + lower II than white

Limit These — High II

🔴 Use Cautiously

White Bread (II 100) — reference; minimal fiber
Wholemeal Bread (II 96) — close to white despite label
Tapioca Starch (II 95) — almost pure fast starch
Instant Oatmeal (II 79) — heavy processing doubles the II vs. rolled oats
White Rice (II 79) — especially short-grain, freshly cooked
Granola (II 70) — depends heavily on added sugars

"The insulin index reveals what the glycemic index often misses: processing matters enormously. Instant oats and rolled oats are the same food at different stages of industrial processing, yet they trigger nearly double the insulin response. The matrix in which starch is delivered to the gut is as important as the starch itself."

InsulinGuru Research Team

insulinguru.com — Evidence-Based Metabolic Nutrition

5. What Affects the Insulin Response of Grains?

5.1 Processing and Milling

The most powerful single predictor of a grain's insulin index is how much it has been processed. When whole grain kernels are cracked, rolled, or finely milled, the physical food matrix that normally slows starch digestion is disrupted. Digestive enzymes reach the starch granules faster, glucose enters the bloodstream more rapidly, and insulin follows.

This is precisely why instant oatmeal (II 79) and rolled oats (II 40) produce such different results despite being the same grain. It is also why finely milled "whole wheat" bread (II 96) triggers almost as much insulin as white bread (II 100).

Key Principle

The more intact the grain's physical structure, the lower its insulin index. Choose the least processed form whenever possible — groats over flakes, cooked whole grain over flour.

5.2 Amylose vs. Amylopectin Ratio

Starches are made of two molecules: amylose (a straight chain, digested slowly) and amylopectin (a branched chain, digested quickly). Grains with a higher amylose proportion tend to have lower insulin indices. Barley and oats are naturally rich in amylose and beta-glucan fiber. Standard white rice has a high amylopectin content, which contributes to its elevated II of 79.

5.3 Fiber Content — Especially Beta-Glucan

Soluble fibers form a gel in the gut that slows gastric emptying and delays glucose absorption. Beta-glucan, found in high concentrations in oats and barley, is particularly effective. This is one key reason why whole rolled oats (II 40) score significantly lower than many comparable grains, and why wheat bran (II 30) is at the bottom of the scale.

5.4 Cooking Method and Duration

Overcooking gelatinizes starch completely, making it rapidly digestible. Al dente pasta (still firm at the center) triggers significantly less insulin than the same pasta cooked soft. Similarly, rice that has been cooked and then cooled develops resistant starch — a form that escapes small-intestine digestion entirely — further lowering the insulin demand compared to freshly cooked hot rice.

5.5 Protein and Fat in the Meal

Eating grains alongside protein and fat slows gastric emptying and blunts the glucose curve. A bowl of oats eaten plain will produce a higher insulin response than the same oats eaten with nuts, seeds, or plain Greek yogurt. This meal-composition principle applies to every grain on this list.

5.6 Individual Variation

Insulin index values reported in research are averages across study participants. Individual responses to the same grain can vary significantly based on gut microbiome composition, insulin sensitivity, the time of day of eating, and prior physical activity. Published II values are useful benchmarks, not precise individual predictions.

6. Practical Guide: Choosing and Preparing Grains

Grain Swaps That Lower Insulin Response Simple substitutions

Instead of…	Try…	II Reduction	Tip
Instant Oatmeal (79)	Rolled Oats (40)	−39 pts	Soak overnight to reduce cooking time
White Rice (79)	Brown or Black Rice (50–62)	−17–29 pts	Cook, cool, and reheat to boost resistant starch
White Rice (79)	Barley or Bulgur (50)	−29 pts	Barley works well in risotto-style dishes
Wholemeal Bread (96)	Pasta al dente (40)	−56 pts	Remarkable difference for the same calories
Granola (70)	Rolled Oats + Nuts (≈40)	−30 pts	Most commercial granolas have added sugars
Couscous (65)	Bulgur (50)	−15 pts	Both from wheat, but bulgur is more intact

Preparation Tips That Work for Any Grain

1. Don't overcook. Stop cooking pasta, rice, and oats while still slightly firm. A few extra minutes on the stove significantly increases the speed of starch digestion.

2. Cool and reheat. Cooked and cooled grains form more resistant starch. Meal-prepped grains eaten the next day are metabolically "better" than freshly cooked ones.

3. Add an acid. A splash of lemon juice or a little vinegar added to grain dishes can lower the insulin response by slowing gastric emptying. This is a practical, research-backed hack.

4. Pair with protein and fat. Never eat a large serving of grains alone. Combine with eggs, legumes, nuts, olive oil, or full-fat yogurt to blunt the insulin spike significantly.

5. Control portion size. Even low-II grains can generate a high insulin response in large amounts. A standard serving of 40–60 g dry grain is appropriate for most adults.

7. Sample Day of Low–Insulin-Index Grain Meals

The following example shows how to build an entire day of eating centered on grains with low or moderate insulin indices — without sacrificing variety or satisfaction.

Breakfast

Overnight Rolled Oats

50g rolled oats soaked overnight, 1 tbsp chia seeds, handful walnuts, ½ cup plain yogurt, berries

II ≈ 38–42

Lunch

Bulgur & Chickpea Bowl

60g cooked bulgur, chickpeas, cucumber, tomato, parsley, tahini dressing, lemon

II ≈ 45–50

Dinner

Buckwheat with Salmon

60g cooked buckwheat groats, baked salmon fillet, steamed broccoli, olive oil, garlic

II ≈ 42–50

Result

This day uses grains as a background element — never as the sole focus of a plate. Protein, fat, fiber, and vegetables accompany every grain serving, which consistently produces lower postprandial insulin levels than the grain values in the table above would suggest on their own.

8. Frequently Asked Questions

Is the insulin index the same as the glycemic index for grains? +

No. For grains and starchy foods, the GI and II often track closely — both are elevated for refined white flour products and lower for intact whole grains. However, the II also captures insulin stimulated by protein and other food components, making it a broader measure. For protein-rich foods the difference is large; for pure starchy grains, the two indices are more correlated but still diverge in meaningful ways, especially after processing.

Why is wholemeal bread almost as high as white bread on the insulin index? +

Commercial wholemeal bread is made from finely milled whole wheat flour. Even though all the bran and germ are technically present, the particle size is tiny — similar to white flour — so starch digestion is fast and insulin response is high. The physical food matrix is what matters, not just the ingredient label. Traditional stone-milled sourdough with coarsely ground flour produces a significantly lower insulin response than industrial wholemeal bread.

Can people with type 2 diabetes eat oats? +

Whole rolled oats (II 40) are generally well-tolerated by people with type 2 diabetes and are frequently recommended by dietitians. The beta-glucan fiber in oats helps modulate the glucose and insulin response. Instant oatmeal (II 79), on the other hand, should be limited. Oats should always be paired with protein and fat for the best blood sugar outcome. Individual responses vary, and personal glucose monitoring after eating is the most reliable way to assess tolerance.

Is quinoa a good low-insulin grain option? +

Quinoa has a moderate insulin index of approximately 55, placing it in the moderate range — better than white rice or bread, but not as low as barley, oats, or buckwheat. Quinoa is technically a seed ("pseudocereal") rather than a true grain, and it offers a complete amino acid profile, which adds to its nutritional value. For someone managing insulin levels, quinoa is a reasonable choice when portioned appropriately and combined with fat and vegetables.

Does soaking or fermenting grains lower their insulin index? +

Yes, both can help. Soaking grains activates phytase enzymes that reduce phytic acid (which otherwise slows mineral absorption) and can slightly soften starch structures. Fermentation (as in sourdough bread) lowers the overall starch content via microbial consumption, produces organic acids that slow gastric emptying, and can meaningfully lower both GI and II compared to non-fermented versions of the same grain. Traditional sourdough from whole grain flour is significantly better metabolically than commercial wholemeal bread.

Which grain has the lowest insulin index overall? +

Among common grains and grain products, wheat bran has the lowest insulin index at approximately 30, though it is typically used as a supplement or ingredient rather than eaten alone as a standalone meal. Among whole grains eaten as a main component of a meal, whole rolled oats, al dente pasta, amaranth, and teff all score around 40–45. Barley, buckwheat, bulgur, and spelt cluster around 50 and represent excellent whole grain choices.

9. Key Takeaways

🌾

Processing drives the score Rolled oats score 40; instant oats score 79. Choose the least processed form of every grain — groats, whole berries, or al dente pasta over fine flour.

📉

Bread is rarely a low-II choice Both white (100) and commercial wholemeal bread (96) sit at the top of the insulin index scale. Even "healthy" bread can be a high-insulin food.

❄️

Cool and reheat to lower II Cooked and cooled grains develop resistant starch, reducing their insulin impact. Meal-prepped rice or pasta is metabolically preferable.

🥦

Never eat grains alone Protein, fat, fiber, and vegetables all blunt the insulin response of any grain. The meal context often matters as much as the grain choice itself.

🏆

Top performers: bran, oats, barley, buckwheat These four grain options consistently produce the lowest insulin responses and are supported by strong research evidence.

⚗️

Ancient grains are generally favorable Spelt, farro, teff, amaranth, and sorghum all sit in the low-to-moderate range, offering nutritional variety without the insulin spike of refined grain products.

References & Further Reading

Holt SH, Miller JC, Petocz P. An insulin index of foods: the insulin demand generated by 1000-kJ portions of common foods. Am J Clin Nutr. 1997;66(5):1264–76.
Brand-Miller JC, et al. Glycemic index, postprandial glycemia, and the shape of the curve in healthy subjects: analysis of a database of more than 1000 foods. Am J Clin Nutr. 2009;89(1):97–105.
Augustin LS, et al. Glycemic index, glycemic load and glycemic response: An International Scientific Consensus Summit from the International Carbohydrate Quality Consortium (ICQC). Nutr Metab Cardiovasc Dis. 2015;25(9):795–815.
Wolever TM. Is glycaemic index (GI) a valid measure of carbohydrate quality? Eur J Clin Nutr. 2013;67(5):522–31.
Tosh SM. Review of human studies investigating the post-prandial blood-glucose lowering ability of oat and barley food products. Eur J Clin Nutr. 2013;67(4):310–7.
Östman EM, et al. Inconsistency between glycemic and insulinemic responses to regular and fermented milk products. Am J Clin Nutr. 2001;74(1):96–100.
Baxter AL, et al. Low glycaemic index diets and healthy diets for people with type 2 diabetes. Cochrane Database Syst Rev. 2019.
Zafar TA, et al. Comparing whole grain and refined wheat bread as breakfast: effect on blood glucose and insulin responses. Nutr J. 2017;16(1):6.