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.

The Dangers of High Insulin Index Foods | InsulinGuru

Metabolic Health

The Dangers of High Insulin Index Foods

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.

Why your insulin response matters far more than just calories — and how certain everyday foods silently drive obesity, insulin resistance, and chronic disease.

InsulinGuru Research Team

insulinguru.com

| Updated April 20, 2025 | 12 min read | Evidence-based

You've heard about the glycemic index. You may even track your sugar intake. But there's a lesser-known — and arguably more important — measure that determines how your body stores fat, regulates hunger, and ages metabolically: the insulin index (II).

Some foods trigger an outsized insulin response far beyond what their carbohydrate content alone would predict. Yogurt, white bread, certain protein bars, and even foods labeled "sugar-free" can spike insulin dramatically — promoting fat storage, suppressing fat burning, and, over time, setting the stage for insulin resistance, type 2 diabetes, and cardiovascular disease.

This article provides a thorough, evidence-based look at why high insulin index foods are harmful, which foods are most problematic, and what you can do to make smarter dietary choices for long-term metabolic health.

537M

Adults worldwide living with diabetes (IDF, 2021)

~40%

Of US adults have insulin resistance or prediabetes

2–3×

Higher cardiovascular risk linked to chronic hyperinsulinemia

1. What Is the Insulin Index?

The Insulin Index (II) measures the insulin response elicited by a 1,000 kJ (239 kcal) serving of a food, benchmarked against the same caloric portion of white bread, which is assigned a score of 100.

The concept was first systematically studied by researchers Susanne Holt, Jennie Brand-Miller, and colleagues at the University of Sydney in the 1990s. Their landmark 1997 paper in the American Journal of Clinical Nutrition showed that the insulin response to food correlates only modestly with glycemic index — meaning a food can have a moderate glycemic index yet still trigger a powerful insulin spike.

Key Definition

Insulin Index ≠ Glycemic Index

Glycemic index measures blood glucose rise. The insulin index measures insulin secretion directly. Protein-rich foods (like beef or fish) can have a near-zero glycemic index but a surprisingly moderate-to-high insulin index. This is why II is a more complete picture of metabolic impact.

0–50 Low

51–100 Moderate

101+ High / Very High

Insulin Index scale. White bread = 100 (reference). Lower is generally better for metabolic health.

2. How High-II Foods Harm Your Body

When you eat a high insulin index food, your pancreas releases a surge of insulin into the bloodstream. In small, infrequent doses, this is normal and healthy. The problem arises when this happens repeatedly — multiple times per day, every day — which is exactly the pattern of a modern Western diet.

Insulin spike triggers fat storage Insulin is the primary anabolic hormone. It signals fat cells (adipocytes) to absorb fatty acids from the bloodstream and inhibits the enzyme lipase, which normally breaks down stored fat. High II foods lock the body into a fat-storage mode.

Fat burning is suppressed for hours Elevated insulin levels suppress lipolysis — the mobilization of stored fat for energy. After a high-II meal, fat oxidation can remain blunted for 4–6 hours, meaning the body is essentially unable to burn its own fat reserves during that window.

Blood sugar crashes → cravings return A rapid insulin spike is followed by a reactive drop in blood glucose. This hypoglycemic dip triggers hunger signals, cravings for sugary or starchy foods, irritability, and fatigue — creating a vicious cycle of repeated high-II eating.

Cells become insulin resistant over time Chronically elevated insulin downregulates insulin receptor sensitivity in muscle, liver, and fat cells. The pancreas must secrete ever-larger quantities of insulin to achieve the same effect — a defining feature of type 2 diabetes progression.

Systemic inflammation increases High insulin levels promote the production of pro-inflammatory cytokines and reactive oxygen species. This chronic low-grade inflammation underlies atherosclerosis, certain cancers, non-alcoholic fatty liver disease (NAFLD), and accelerated aging.

⚠ Important

Even lean individuals who eat a diet dominated by high insulin index foods can develop metabolic dysfunction — including visceral fat accumulation, elevated triglycerides, and reduced HDL cholesterol — despite appearing healthy by weight alone.

3. The Worst Offenders: High-II Foods Ranked

The table below lists foods with the highest measured insulin index scores, based on published research including the seminal Holt et al. (1997) study and subsequent replication data. All scores are relative to white bread (II = 100).

🔴 Highest Insulin Index Foods Source: Holt et al., 1997 & expanded datasets

Food	Category	II Score	Risk Level
Jelly beans / gummies	Candy / sweets	160	🔴 Very High
White bread / baguette	Grain / starch	100	🔴 High
Low-fat flavored yogurt	Dairy	115	🔴 High
Croissant	Baked goods	79	🟠 Moderate–High
Corn flakes / puffed cereals	Breakfast cereal	107	🔴 High
Potato (boiled, white)	Starchy vegetable	121	🔴 High
White rice	Grain / starch	79	🟠 Moderate–High
Chocolate cake	Baked goods / sugar	112	🔴 High
Skim milk	Dairy	60	🟠 Moderate
Potato chips	Ultra-processed snack	61	🟠 Moderate
Whole-grain bread	Grain	60	🟠 Moderate
Eggs	Protein	31	🟢 Low
Beef / fish (plain)	Protein	27–51	🟢 Low
Peanuts / almonds	Nuts / seeds	20	🟢 Low

* II scores may vary slightly by preparation method, portion size, and individual metabolic factors. Scores shown are averages from published research. Explore the full InsulinGuru database →

4. Diseases Linked to Chronic Insulin Spikes

The consequences of repeatedly consuming high insulin index foods extend far beyond weight gain. Decades of epidemiological research and clinical studies now link chronic hyperinsulinemia — persistently elevated insulin — to a wide spectrum of serious diseases.

🩸

Type 2 Diabetes

Chronic insulin spikes progressively exhaust pancreatic beta cells and drive insulin resistance in peripheral tissues. A 2019 meta-analysis in Lancet Diabetes & Endocrinology confirmed dietary glycemic load (closely linked to II) as a significant predictor of T2D incidence.

❤️

Cardiovascular Disease

Insulin promotes endothelial dysfunction, increases triglycerides, lowers HDL cholesterol, and accelerates arterial plaque formation. Hyperinsulinemia is an independent risk factor for heart attack and stroke, separate from obesity.

🧠

Alzheimer's Disease

Increasingly called "Type 3 Diabetes," Alzheimer's pathology involves brain insulin resistance. Research from Brown University found that brain cells in Alzheimer's patients show impaired insulin signaling similar to peripheral insulin resistance.

🎗️

Certain Cancers

Insulin and IGF-1 are potent growth signals. Elevated insulin promotes cell proliferation and inhibits apoptosis. Obesity-related cancers including breast, colon, endometrial, and pancreatic cancer are strongly associated with chronic hyperinsulinemia.

🫀

Non-Alcoholic Fatty Liver (NAFLD)

Insulin drives de novo lipogenesis in the liver — the conversion of excess carbohydrates into fat. Combined with impaired fatty acid oxidation, this leads to hepatic fat accumulation and, in advanced cases, cirrhosis and liver failure.

⚡

Polycystic Ovary Syndrome (PCOS)

Hyperinsulinemia stimulates ovarian androgen production, disrupting ovulation and hormonal balance. Up to 70% of women with PCOS have insulin resistance, and dietary II reduction is a core therapeutic target.

"Insulin is not just a blood sugar regulator — it is the master hormonal switch that determines whether your body is in a state of building and storing, or breaking down and burning. When that switch is chronically flipped to 'store,' the metabolic consequences are profound and far-reaching."

Dr. Robert H. Lustig

Neuroendocrinologist, UCSF · Author of Metabolical

5. Surprising Foods with a High Insulin Index

Many people are shocked to discover that several foods marketed as "healthy," "light," or "diet-friendly" carry a disproportionately high insulin index. This disconnect exists because the food industry optimizes for glycemic index and calorie content while often ignoring insulin response.

⚠ Watch Out For

These foods are commonly perceived as healthy but trigger a higher insulin response than many people expect.

🥛 Low-Fat Flavored Yogurt

Insulin Index: ~115
Despite a "probiotic" health halo, most commercial flavored yogurts are loaded with added sugars to compensate for reduced fat.
Better swap: Plain full-fat Greek yogurt (II ~62)

🥣 Breakfast Cereal (even "whole grain")

Insulin Index: 79–120+
Extrusion processing destroys fiber structure, making starch rapidly digestible regardless of whole-grain labeling.
Better swap: Rolled oats with nuts (II ~40)

🍞 "Multigrain" Bread

Insulin Index: ~70–90
Multigrain ≠ whole grain. If refined flour is the first ingredient, II remains high despite seeds or grains on the label.
Better swap: Dense rye or sourdough bread (II ~50–60)

🍌 Overripe Banana

Insulin Index: ~84
As bananas ripen, resistant starch converts to free sugars. An unripe banana has a significantly lower II (~45).
Better swap: Unripe (slightly green) banana or berries

🥤 "Sugar-Free" Flavored Milk Drinks

Insulin Index: ~90–120
Dairy proteins (particularly whey) are potent insulin secretagogues independent of sugar content. "Sugar-free" doesn't mean low insulin response.
Better swap: Unsweetened almond or oat milk (II ~25–35)

Lowest II Options

✅ Low-II Alternatives

Eggs — II: ~31
Almonds / walnuts — II: ~20
Avocado — II: ~25
Leafy greens — II: ~15
Olive oil — II: ~3
Lentils (cooked) — II: ~58

6. What To Do Instead

Reducing your dietary insulin load doesn't require extreme restriction. The goal is not to eliminate all carbohydrates, but to choose foods that produce a proportionate, moderate insulin response — allowing insulin to do its job without chronically overloading the system.

Practical Strategies to Lower Your Insulin Load

🌿

Prioritize whole, minimally processed foods Processing destroys the fiber matrix and cell structure that slows digestion and blunts insulin response. Choose intact grains over flour products, whole fruit over juice, and real food over bars or shakes.

🥚

Build meals around low-II proteins and fats Eggs, fatty fish, nuts, olive oil, and avocado have low II scores and promote satiety without large insulin spikes. Pair them with non-starchy vegetables and small portions of low-II starches.

⏱️

Allow insulin to fall between meals Constant snacking on high-II foods prevents insulin from returning to baseline. Give your body 4–5 hours between meals without snacking to restore insulin sensitivity and enable fat oxidation.

🧪

Use the InsulinGuru database before you shop Our database contains insulin index values for 400+ foods. Before making a substitution or trying a new product, check its II score. Knowledge is the most powerful dietary tool available.

🥗

Sequence your meals: vegetables and protein first Research by Alpana Shukla (Cornell) showed that eating vegetables and protein before carbohydrates in a meal significantly blunted the subsequent glucose and insulin peak — without changing what you eat, only the order.

🚶

Walk 10–15 minutes after eating A short post-meal walk engages muscle glucose uptake via non-insulin-dependent pathways, reducing the insulin needed to clear post-meal glucose. This simple habit measurably improves insulin sensitivity over time.

✅ Key Insight

You don't need a perfect diet. Reducing your average insulin load by even 20–30% through food swaps and meal timing can meaningfully improve fasting insulin, body composition, and long-term metabolic health markers over a period of weeks to months.

7. Frequently Asked Questions

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

No. The glycemic index (GI) measures how much a food raises blood glucose. The insulin index (II) measures the actual insulin response. They often correlate but can diverge significantly — particularly for protein-rich foods (which trigger insulin but not glucose) and dairy products. II is generally considered a more complete metabolic measure.

Can lean people be harmed by high insulin index foods? +

Yes. Metabolic dysfunction driven by chronic hyperinsulinemia can occur in normal-weight individuals — a phenomenon researchers call "TOFI" (Thin Outside, Fat Inside). Lean people who consume high-II diets can develop visceral fat, fatty liver, and insulin resistance without visible weight gain. Weight is not a reliable proxy for metabolic health.

Why does dairy have a high insulin index despite low sugar? +

Dairy proteins — particularly whey — are potent insulin secretagogues. Whey is rapidly digested and contains branched-chain amino acids (BCAAs) and insulinotropic peptides that directly stimulate pancreatic beta cells. This is why low-fat dairy (which has more protein per calorie, proportionally) often has a higher II than full-fat dairy.

Does cooking method change the insulin index of food? +

Yes, significantly. Cooking and processing affect starch digestibility. For example, cooling cooked potatoes or rice increases resistant starch content, lowering the II. Al dente pasta has a lower II than overcooked pasta. Baking vs. boiling, fermenting (as in sourdough), and sprouting grains can all meaningfully reduce the insulin response.

Should people with type 2 diabetes strictly avoid high-II foods? +

People with type 2 diabetes should work with a registered dietitian or endocrinologist to design a dietary plan. In general, reducing dietary insulin load is beneficial for glycemic control, but specific targets depend on medications, current insulin sensitivity, and individual response. The InsulinGuru database is a useful reference tool, but it does not substitute for personalized medical advice.

Is fruit dangerous because of its sugar content and high II? +

Most whole fruits have a moderate-to-low II due to their fiber content, water, and fructose composition (fructose raises insulin less than glucose). Berries, apples, pears, and citrus have particularly low II scores. Fruit juice, dried fruit, and overripe fruit behave more like sugar, with correspondingly higher insulin responses. Whole fruit in reasonable amounts is not a concern for most people.

Scientific References

Holt SHA, Miller JCB, 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):1264–1276. doi:10.1093/ajcn/66.5.1264
Willett W, Manson J, Liu S. "Glycemic index, glycemic load, and risk of type 2 diabetes." Am J Clin Nutr. 2002;76(1):274S–280S.
Nuttall FQ, Gannon MC. "Plasma glucose and insulin response to macronutrients in nondiabetic and NIDDM subjects." Diabetes Care. 1991;14(9):824–838.
Lustig RH. Metabolical: The Lure and the Lies of Processed Food, Nutrition, and Modern Medicine. New York: Harper Wave; 2021.
Shukla AP, Iliescu RG, Thomas CE, Aronne LJ. "Food Order Has a Significant Impact on Postprandial Glucose and Insulin Levels." Diabetes Care. 2015;38(7):e98–e99.
International Diabetes Federation. IDF Diabetes Atlas, 10th edition. Brussels; 2021. Available at: diabetesatlas.org
de Mello VD, Schwab U, Kolehmainen M, et al. "A diet high in fatty fish, bilberries and wholegrain products improves markers of endothelial function and inflammation in individuals with impaired glucose metabolism in a randomised controlled trial." Diabetologia. 2011;54(11):2755–2767.
Nuttall FQ, Mooradian AD, Gannon MC, et al. "Effect of protein ingestion on the glucose and insulin response to a standardized oral glucose load." Diabetes Care. 1984;7(5):465–470.