What’s the insulin index & how to use it?
Chronically elevated insulin levels (hyperinsulinemia) are a major driver of insulin resistance, if not the main driver . The Insulin index helps you to choose foods that don’t cause hyperinsulinemia. When you’re trying to prevent or reverse insulin resistance – the bad kind, called pathological insulin resistance – knowing the insulin index of food is a useful measurement.
Although the insulin index on its own is a great tool, it’s not the be-all end-all of nutrition. For this reason, Nutrita recommends using it alongside the Nutrient density score. Together, they help you select metabolically friendly foods that also provide complete nutrition.
The food insulin index ranges from 0 – 100 representing how much insulin your body releases within 2 hours of having eaten a particular food, obtained against a standard reference ‘food’ (white bread) with a score of 100. For comparison, all food portions contain the same amount of calories (240 kcal) .
The index can help you identify foods that are likely to minimize your lifetime insulin secretion, a great thing for metabolic flexibility that’s defined as your body’s ability to switch between using glucose or fat as needed. Minimizing insulin secretion over a lifetime is also great for overall health and longevity .
The insulin index is based on clinical data on a limited number of foods. When applied to a wider number of food, it is an estimate. A reliable insulin index of foods isn’t easy to find, but Nutrita has you covered. To find the index of a particular food, just enter it in our food search engine. Keep in mind that the true amount of insulin someone releases in response to a particular food or combinations of foods is somewhat individual.
Responses to the macronutrients protein and especially fat are less variable (a good thing!) but responses to carbohydrates are much more variable . It depends, among other factors, on your degree of insulin resistance, how full of glycogen your muscles and liver are, the medications you may be on and possibly even on your mix of gut microbiota [5,6,7]!
The insulin index is useful comparing different foods against one another fairly. By fair, we mean that we compare 100 kcals of apple to 100 kcals of glucose. But in the real world, we’ll want to know how actual amounts of foods we eat affect our metabolic response. For example, you’ll want to how much insulin your morning teaspoon of sugar in your coffee produces versus the 3 apples you snack on throughout the day. That comparison requires knowing their food insulin loads, not insulin indexes.
The food insulin load tells you how much insulin is secreted after eating a certain amount of a particular food. What are the units for the insulin load? 1 point on the insulin load is equivalent to the amount of insulin secreted from eating 1 gram of glucose. So an insulin load of 10, say, is equivalent to the amount of insulin secreted from 10 g of glucose.
If you dig around our food search engine, you’ll see that two foods may have a similar insulin index but vastly different insulin loads – how can this be?
This is because we eat some foods in small quantities and other foods in large ones, and the insulin load reflects this. For example, garlic powder has a Poor insulin index score of 59%, as do potatoes with a score of 56%. However, the insulin load from a typical 2.5 g serving of garlic powder is extremely low at 1. Contrast that with a typical cup (or 150 g) serving of potatoes which carries a relatively large insulin load of 21. The insulin load thus ensures you’re correctly choosing foods even after taking into account the quantities in which you’re likely to eat them.
The dietary insulin load is also great to compare how much each food in your diet contributes to your total dietary insulin load. The insulin load for a food is obtained by combining the insulin index of that food with how much was eaten and how often. The formula is:
[insulin index of food / 239 kcals] X [kcals per serving(s) you ate] X [servings per day] X 0.6
You could see, for example, that bread contributes to 40% of your dietary insulin load, fruit 24% and spices like garlic powder 3%. Knowing the total calories in your diet, we can work out the insulin load of your diet per calorie eaten. For health and longevity, staying on the lower side of the latter is better. But don’t worry, Nutrita Pro calculates all of this for you to make it crystal clear how your diet is performing in terms of insulin burden.
Nutrita’s insulin index is a great way to minimize your lifetime exposure to unnecessarily high levels of insulin. Don’t think this means insulin is a bad guy – it isn’t. It’s a life-giving hormone, a master regulator of how your body partitions energy. However, it’s powerful and should be called upon infrequently and sparingly, meaning you shouldn’t be snacking.
The insulin index allows you to choose foods that will cause you to secrete physiological (i.e. healthy, normal) levels of insulin. This helps keep hyperinsulinemia at bay. By using the insulin index, it’ll become clear to you which of the three macronutrients (carbs, protein and fat) cause you to secrete more insulin:
- Carb rich foods are the most insulinogenic – think sugary or starchy foods like bananas or potatoes, respectively
- Protein rich foods are the second most insulinogenic – think chicken and cod fish
- Fats like butter or fatty foods like bacon are the least insulinogenic
The insulin index can help you avoid foods that cause hyperinsulinemia – which is super important. But you can get even more out of it by combining it with our Nutrient density score. Why is that?
Some foods are low on the insulin index but aren’t nutritious (e.g. olive oil). So if you were only considering the insulin index, you could be misled into thinking a food low on the insulin index is a better choice for you than it really is. In the case of olive oil, it’s fine as a seasoning for your salad (i.e. a minor source of your total calories) but not as a staple which should contribute the bulk of your nutritional requirements. By combining our Nutrient density score with our Insulin index, you can benefit from foods that trigger healthy metabolic responses and provide lots of high-quality nutrition.
As a rule of thumb, try to choose foods that are both
- between Good and Moderate on our Insulin index
- between OK to Good on our Nutrient density score
The glycemic index indicates the extent to which blood glucose rises after ingesting a food . It ranges from 0 – 100. It represents how much your blood sugar has risen 2 hours after having eaten a particular food relative to glucose, setting the reference at 100. Foods with the same glycemic load (carb content) can cause different increases in blood sugar levels. This is because the rise in blood sugar does not only depend on the carb content, but also on the mix of indigestible fibers, protein, fat, viscosity and other factors [9,10,11].
Similarly, the insulin index indicates the rise in insulin. Carbs are broken down to sugar and elicit a rise in blood sugar. This is followed by an increase in insulin which takes glucose out of the bloodstream to get it into tissues, thereby lowering blood sugar levels. Because refined carbs are both high up on the insulin index and glycemic index, you could be tricked into thinking that the insulin and glycemic index are basically the same. They’re not.
Here’s why the insulin index is a better measure than the glycemic index: the insulin index will tend to catch foods that raise insulin and blood sugars excessively. The glycemic index however will miss a considerable number of foods don’t raise blood sugars excessively but do so at the cost of raising insulin excessively (as insulin takes sugar out of the bloodstream and stuffs it into cells).
Why controlling your food insulin index helps with diabetes, obesity, and overall health?
Well regulated insulin signaling is crucial for the proper partitioning of energy in the body. Much of overall health comes down to how well cells handle their moment to moment, finely tuned energy needs. Impairments in insulin signaling can interfere with this fine tuning and eventually manifest as obesity, diabetes and other diseases.
Insulin and overall health
Keeping insulin low over a lifetime may be the single biggest factor in your control to live a long and healthy life . Insulin is a hormone produced by your pancreas. It takes amino acids (the building blocks of protein) and sugar out of your bloodstream and into your cells so that they can be used. Insulin is also a neuropeptide, meaning your brain produces it ‘locally’ for its own needs. Insulin acts pretty much everywhere in the body and impacts many other key pathways, such as mTOR, the master regulator of growth .
The importance of keeping insulin low and maintaining proper insulin signaling is best understood through its role in Metabolic Syndrome. Metabolic Syndrome is a constellation of four markers: high blood pressure, high blood sugars, large waist circumference (excess body fat) and high triglycerides. Together they all point to a poorly functioning metabolism. Hyperinsulinemia is the major factor thought to cause Metabolic Syndrome . So when insulin levels are successfully lowered, Metabolic Syndrome can be mitigated or even reversed.
Avoiding Metabolic Syndrome reduces your risk for nearly every modern chronic disease you can name, such as Alzheimer’s, cardiovascular disease, obesity, cancer and diabetes.
Insulin and obesity
Insulin is a storage hormone, especially a fat storage hormone . Energy from your diet is either stored as glycogen in the liver or as fat in fat tissues. For this reason, chronically high insulin levels make it very difficult to lose body fat. In fact even when calories are restricted, people may still struggle with fat-loss as long as their biology remains tilted towards energy storage, largely due to high insulin levels [16,17].
This is clearly seen in patients on insulin therapy who can’t help but gain a lot of weight and fatten up [18,19]. Type 1 diabetics who don’t have access to enough insulin will suffer from an insulin deficiency and so lose dangerous amounts of weight (from fat and muscle)! And if those same diabetics then inject too much insulin, they will fatten up. So does this mean that in order to lose body fat all we need to do is to keep our insulin levels super low? No, it’s not quite that simple. But keeping insulin levels low and not stimulating insulin release too often remains crucial.
Reducing dietary carbohydrates is a great way to achieve this due to its insulin lowering effects. Dr. Ludwig’s 2018 study demonstrates this: for every 10% reduction of calories from dietary carbohydrate, you can benefit from an extra 52 kcal per day energy deficit . This is a great strategy to adopt given that you only need to ‘overeat’ 21 kcals per day (equivalent to a bite of an apple) to gain 21 lbs (~ 10kg) of fat over a decade . As no one can count calories accurately enough (i.e. < 1% accuracy) to maintain good body composition over decades, it’s important to adopt these sort of self-regulating strategies.
There’s also evidence suggesting that high omega-6 seed oils are obesogenic due to their effect on fat cells . They’re thought to make fat cells more sensitive to insulin (i.e. prone to fat storage) but not contributing to whole-body insulin sensitivity (i.e. the healthy kind of insulin sensitivity). So although high omega-6 seed oils are technically low on our Insulin index they’re definitely on our list of bad fats.
Insulin index and diabetes
Hyperinsulinemia (chronically elevated insulin levels) is the primary driver of insulin resistance, the characteristic feature of type 2 diabetes. This pathological insulin resistance means that cells become less responsive to insulin. Consequently, more and more insulin is needed to do the same job, turning it into a vicious cycle.
To reverse insulin resistance, patients with diabetes are best served by avoiding foods that abnormally stimulate insulin. In practice, this means both reducing total carbohydrate intake and especially the worst sources such as refined carbs (i.e. flour products) and sugars.
Although dietary carbohydrate restriction as a medical treatment for diabetes dates back to over a century, it’s only recently been re-discovered as an effective treatment. The telemedicine company Virta Health has conducted clinical trials showing an astonishing 60% reversal of the condition in long-standing diabetics after a year, defined as an HbA1c of < 6.5% . Virta uses a ketogenic diet, a strongly carbohydrate restricted diet. This diet keeps insulin levels low enough to liberate sufficient fat that some of it can be turned into ketone bodies – which is where the diet gets its name. These ketone bodies don’t just supply energy to your cells, they’re also crucial signaling molecules that beneficially impact many of the problems in diabetes such as oxidative damage and chronic inflammation [24,25].
Bottom line: It makes sense to keep insulin low and not stimulate it too often by snacking throughout the day. However, insulin alone is not the whole story. For this reason, we not only provide Insulin index but also a Keto score and a Nutrient density score. If you want to know whether something is keto, you should keep an eye on the keto score. And the bulk of your calories should come from foods that score high on our Nutrient density score to ensure that your diet is nourishing irrespective of its carbohydrate content.
Ketones and blood insulin levels are useful to track!
Levels of blood ketones increase in the blood when insulin levels drop, usually because a person isn’t eating or significantly restricting dietary carbs. Dietary protein can stimulate insulin and thus somewhat lower blood ketones, but not nearly as much as carbs will. People who are very insulin resistant may want to keep an eye on their protein intake to achieve their desired level of ketosis. However, if you’re struggling to get into ketosis it’s better to lower carbs to achieve your goal before you restrict high-quality animal protein. High-quality animal protein should never be restricted to the extent where essential nutrients are lacking, the immune system is compromised, or healthy amounts of muscle mass cannot be maintained.
Your sensitivity to insulin’s effects changes throughout the day, peaking in the morning and dropping in the evening and night . Avoiding snacking (especially late night snacking) and eating only 2 – 3 times a day is a great way to keep insulin low and thus sensitive to its actions [27,28].
Tracking your blood, breath or urine ketone levels when starting a ketogenic diet for the first time is an excellent way to check whether or not you’re actually in ketosis, also indicative of your insulin levels being low throughout much of the day – a good thing!
If you’re unsure about which foods will keep your insulin low but still provide you with nutritious meals, use our mobile app to scan a food’s barcode or search for it in our food search engine. This will give you its Insulin index, Keto score and Nutrient density score.
Why it’s important to check the insulin index when buying food?
The insulin index of foods can provide simple help for people to choose foods with a low insulin burden. This is important because many amongst us are diabetic and don’t yet know that diabetes is a problem of hyperinsulinemia (excessive insulin secretion) – high blood sugars are just a symptom of the disease at the advanced stage. Hyperinsulinemia is at the root of or substantially contributes to many other health conditions, such as obesity, Alzheimer’s and cancer [29,30,31].
Avoiding insulinogenic foods and not eating too often thus becomes a first line approach to fend off hyperinsulinemia. The insulin index can help lower one’s overall insulin burden. It’s important to note that this can be done while maintaining a nutrient-dense diet with a full spectrum of essential amino (protein) and fatty acids (fat). This is achieved by combining the insulin index with our nutrient density score.
The vast majority of junk-food nowadays is characterized by being highly insulinogenic and severely lacking in nutrients. Taking Papa John’s 14” regular thin crust pizza for example. You can see that it scores Poor on the insulin index at 37% and Poor in terms of nutrient density with a 4 out of 10. Now take bread, which isn’t even considered junk-food by most people. It scores Poor on the insulin index at 43% and Bad in terms of nutrient density with a score of 2 out of 10.
What do bread and pizza all have in common?
- Highly insulinogenic
- Added sugars
- Low nutrient density
- Bad fats most likely (high-omega 6 seed oils)
These are precisely the dietary factors Nutrita advises people to avoid.
What foods raise insulin levels the most?
Brown sugar ranks amongst the most insulinogenic foods with a score of 93%. You guessed it, it’s also nutrient poor.
There can be a big difference in insulin secretion and blood sugar levels between 2 different foods that both have 100g of carbs, like rice flour and brown rice, say. The boiled brown rice has a score of 45 while the rice flour (‘bubble rice’) reaches 94!
Nevertheless, the fewer the net carbs a food has, the lower its insulin index is likely to be. This is, however, not always the case, and the prime example is protein. Protein causes insulin release and has a higher insulin index than fat, but only has a mild (i.e. healthy) effect on blood sugars [32, 33].
High-carb meal: insulin shoots up, glucagon drops
After eating a high-carb meal, blood glucose rises, promptly followed by a rise in insulin. In this scenario, as long as insulin is high, glucagon is low. As soon as blood glucose and insulin levels drop, glucagon goes up. Glucagon stimulates the breakdown of glycogen into glucose and thereby ensures that blood sugar levels keep stable.
It’s important to know that insulin does more than lower blood glucose. It’s also, or primarily, a storage hormone, which promotes fat storage. Glucagon on the other hand, triggers the breakdown of fat (lipolysis) . For fat to be used as energy, it has to be broken down into smaller parts (fatty acids and glycerol). In this regard, lipolysis does not equal fat burning, but it is an essential first step in making stored fat accessible, so that the body (e.g. muscle cells and other organs) can use it as a source of energy.
Eating a lot of refined carbs is therefore a very efficient method to inhibit lipolysis – especially when the time between meals is short, such that insulin hardly has time to come down in between meals. Carb-rich foods – especially refined carbs like sugar and flour – trigger people to snack and lead to fat gain .
The scenario looks different when insulin is raised by protein.
Protein-rich meal: insulin and glucagon are released
Let’s first clarify why protein stimulates insulin release. Insulin does not only facilitate the uptake of glucose from the blood, but it is also needed for the absorption of amino acids (the building blocks of proteins) . Because protein does not cause a direct increase in blood sugar, this insulin release would cause a drop in blood sugar. To prevent this, protein does not only lead to a rise in insulin but also in glucagon . Glycogen is broken down, and glucose is released into the blood.
Indeed, a diet that is relatively high in protein and low in carbs is known to improve insulin sensitivity [38, 39, 40]. By raising glucagon, eating protein-rich foods keeps fat stores accessible. This may be one of the reasons why protein is very satiating and provides also a high level of satiety . A protein-rich meal makes you feel full (it’s satiating) and at the same time keeps you full for a long time (it provides satiety). This makes it easy to extend the time in between meals – not eating anything is the safest way to make sure that insulin stays low.
In this regard, the insulin/glucagon ratio is more important than the absolute insulin level [42, 43]. While a high insulin/glucagon ratio inhibits the release of fatty acids and the breakdown of glycogen, a low insulin/glucagon ratio stimulates the mobilization of stored energy.
So for a given rise in insulin from carb-rich versus protein-rich foods, there are different metabolic consequences. What explains that? Lets use an example to understand the difference.
If you’ve looked up white fish in our app, like cod for instance, you might notice that it’s high up on the insulin index (40%) – so does that mean it’s bad for you? No, because although it does elevate insulin substantially it does so within a different hormonal and metabolic context. Hormones like glucagon are strongly stimulated with the cod but not, say, peas. The cod thus leads to an overall healthier metabolic response than the peas . This is why codfish is labelled as Moderate, while peas with an insulin index of 40% are labelled as Poor.
Our scoring system thinks this through for you. You get a simple label to let you know if, overall, this food is in line with your dietary or health goals or not.
Insulin index labels
0 to 30%
More than 30% and a Keto score above 6
More than 30% and less than 60%
More than 60%
Did you know?
There is a common misconception that goes something like this: ‘amino acids from protein can be used to make blood sugar, so protein raises blood sugar, and thus diabetics should avoid protein’. Actually, gluconeogenesis is a very energy-intensive process and the body does not convert amino acids into glucose simply because they are available. Gluconeogenesis ensures that blood sugars are kept stable and sufficient to meet obligate glucose needs [45, 46].
Amino acids (protein) simply participates in that important process. In fact, a large amount of protein from a steak, say, barely raises blood glucose. And any small elevations from it isn’t really due to gluconeogenesis but rather to the breakdown of liver glycogen to ensure a stable blood sugar.
This is also why protein-rich food with an elevated insulin index can still have a pretty decent keto score, because the rise in insulin is accompanied by the activation of other, counter-regulatory ‘fat burning’ signals.
Rest assured though, even if the mechanisms still aren’t totally clear, that’s OK – Nutrita makes it easy for you with its labelled scores and clearly set daily target and limits to reach your goals, whether that’s ‘lower blood sugars’ or ‘lose fat’.
This study measured the insulin release within 2 hours after ingesting 38 standardized portions of different foods, including fruit, baked products, carbohydrate-rich foods, protein-rich foods, and breakfast cereals, in healthy men and women.
This study looked tried to improve post-prandial blood sugars in type 1 diabetics after consuming steak, battered fish, poached eggs, low-fat yoghurt, baked beans or peanuts using the food insulin index.
This study looked at the post-prandial insulin and glycemic responses in healthy men given standardized portions of single foods or mixed meal to improve predictions of glycemia and insulin beyond that which can be done with carbohydrate content alone.
The study done in healthy men investigated the effect of animal and plant protein isolates with regards to the insulin to glucagon ratios.
This study looks at the insulin, glucagon, nitrogen and free fatty acid levels following a meal of protein rich foods like beef in healthy male and female subjects.
This study looked at the insulin and glucose response of untreated diabetics to protein rich foods like lean beef, turkey, gelatin, egg white, cottage cheese, fish or soy.
The study measured the effect of different protein rich foods on post-prandial blood glucose, insulin, glucagon levels in healthy normal weight men to see if it could predict subjective reports of satiety.
The insulin index is a useful estimate of how much insulin is released in response to a certain food. Keeping insulin low and not stimulating it too often throughout the day is an excellent strategy to prevent a whole host of diseases. Eating foods that are MODERATE or GOOD on the insulin index is smart. However, not all foods that raise insulin substantially are bad (e.g. fish) and not all foods that keep insulin very low are healthy (e.g. high omega-6 seed oils). For this reason, it’s important to check what label Nutrita gives to a food’s insulin index, as well as choose foods within a wider context (i.e. use the nutrient density alongside it).
Written by Raphael Sirtoli, MSc Biology
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