Cheese is so low on the glycemic index that it doesn’t even receive a GI score. Foods are assigned a glycemic index value based on how much they raise blood sugar after eating a portion containing 50 grams of carbohydrate. Most cheeses contain so little carbohydrate that you’d need to eat an impractical amount to even reach that threshold, which is why standard GI tables leave cheese unranked entirely.
Why Cheese Has No Glycemic Index Rating
The glycemic index measures how quickly carbohydrate-containing foods raise blood sugar. To test a food’s GI, researchers need volunteers to eat a portion containing 50 grams (or sometimes 25 grams) of available carbohydrate. An ounce of sharp cheddar contains roughly 0.4 to 0.6 grams of lactose, its only real carbohydrate. You’d need to eat somewhere around 5 to 6 pounds of cheddar in one sitting to reach the testing threshold.
The International Table of Glycemic Index and Glycemic Load Values, published in the American Journal of Clinical Nutrition, states plainly that cheese, along with meat, poultry, fish, eggs, and salad vegetables, contains so little carbohydrate that “even in large amounts, these foods when eaten alone are not likely to induce a significant rise in blood glucose.” So rather than having a low GI score, cheese essentially falls off the scale.
How Cheese Affects Blood Sugar
Cheese is primarily fat and protein, with almost no carbohydrate to convert into glucose. When researchers studied what happens after people eat cheddar cheese, they found it did not noticeably increase circulating insulin or trigger a blood sugar response in muscle tissue. That’s a meaningful difference from milk, which shares the same protein but contains enough lactose to produce a measurable insulin spike.
The physical structure of cheese plays a role here too. Its solid food matrix slows digestion, creating a slow and persistent release of amino acids into the bloodstream rather than a quick surge. This slower absorption pattern is one reason cheese behaves so differently from liquid dairy. The combination of high fat, high protein, and minimal carbohydrate means cheese is one of the most blood-sugar-neutral foods you can eat.
Lactose Content Varies by Cheese Type
Lactose is the natural sugar in dairy, and it’s the only carbohydrate source in plain cheese. But the amount varies quite a bit depending on how the cheese is made. Aging and fermentation break down lactose, so harder, more aged cheeses tend to contain the least.
- Mozzarella (part skim): 0.08 to 0.9 grams per ounce
- Cream cheese: 0.1 to 0.8 grams per ounce
- Sharp cheddar: 0.4 to 0.6 grams per ounce
- American (processed): 0.5 to 4 grams per ounce
- Cottage cheese: 0.7 to 4 grams per half cup
- Ricotta: 0.3 to 6 grams per half cup
The pattern is clear: hard, aged cheeses like cheddar sit at the bottom of the range, while softer and processed varieties can contain several times more lactose. Even at the high end, these numbers are still tiny compared to a slice of bread (around 12 to 15 grams of carbohydrate) or a piece of fruit. But if you’re tracking every gram, aged cheeses are the most blood-sugar-friendly choice.
Watch Out for Processed Cheese Products
Plain cheese is naturally very low in carbohydrates, but processed cheese products can be a different story. Cheese dips, cheese spreads, and some pre-sliced “cheese food” products often contain added starches, sugars, and thickening agents that increase the carbohydrate count. Common additives in these products include modified starches, pectin, guar gum, and xanthan gum.
A cluster of these additives, found in foods like cheese dips and creamy dairy desserts, has been linked to higher rates of type 2 diabetes in research on ultraprocessed foods. The cheese itself isn’t the problem; the industrial ingredients packed around it are. If keeping blood sugar stable matters to you, stick with whole, minimally processed cheese and check the nutrition label on anything that comes in a jar, can, or squeeze bottle.
Cheese and Type 2 Diabetes Risk
Beyond its negligible effect on blood sugar in the short term, cheese consumption appears to have a protective relationship with type 2 diabetes over time. A large dose-response meta-analysis found that eating about 30 grams of cheese per day (roughly one ounce, or a thumb-sized portion) was associated with a 20% lower risk of developing type 2 diabetes. Another meta-analysis found that 50 grams daily reduced incidence by 8%.
This isn’t just an observational quirk. A Mendelian randomization study, which uses genetic data to test for causal relationships, found that higher cheese intake was significantly associated with lower odds of type 2 diabetes, with risk reductions between 42% and 50% per standard deviation increase in cheese consumption. That’s a strong signal from a study design specifically built to minimize the confounding factors that plague dietary research.
The mechanism likely involves cheese’s effect on insulin sensitivity. Animal studies have tested both regular-fat and low-fat cheese in insulin-resistant subjects and found that both versions improved the body’s ability to regulate blood sugar, with no difference between the two fat levels. This challenges the long-standing dietary advice to always choose low-fat cheese. The saturated fat in regular cheese didn’t worsen glucose control, and the cheese itself appeared to have a beneficial metabolic effect regardless of fat content.
Pairing Cheese With Higher-GI Foods
Because cheese is high in fat and protein with virtually no carbohydrate, it can help blunt the blood sugar impact of foods you eat it with. Fat and protein both slow stomach emptying, which means glucose from carbohydrate-rich foods enters your bloodstream more gradually. Adding cheese to a sandwich, eating it alongside crackers, or melting it over a baked potato won’t eliminate the glycemic effect of those foods, but it will typically soften the spike compared to eating them alone.
A practical portion is about one ounce, roughly the size of your thumb from tip to base. That’s enough to add meaningful fat and protein to a meal without overdoing calories. For the lowest possible blood sugar impact, aged hard cheeses like cheddar, parmesan, and Swiss are your best options, since they contain the least residual lactose and tend to have the highest protein density per ounce.