We often see various commercials and articles or even Facebook feeds, talking about high or low glycemic foods but do we understand the process behind them?

We are told, even since childhood, that we need to have a constant control of what we eat and avoid the consumption of “unhealthy food” and, more important, of sugar. This belief is welded in our minds, however, do we understand what happens?

The blood glucose level, also known as blood sugar, influences the health of the human body. Above-normal blood glucose level is toxic and can cause kidney failure, increase cardiovascular risk or even cause blindness.

What is the glycemic index?

The glycemic index, or glycemic index(GI), represents a number which is associated with a particular type of food and indicates the effect which that exact food has on the blood glucose( blood sugar) within an individual’s body. [1]

Pure glucose represents the standard in calculating the glycemic index(GI) and is given the value of 100.

More precisely, the GI represents the fluctuation (rise) of the blood sugar level within one’s body after the individual has consummated a particular food. The glycemic index may also represent the speed (rapidity) in which the blood sugar rises, however, other factors can also influence the degree of the growth as the quantity contained and eaten with the food.

The glycemic index takes into account the available carbohydrate (deducting the fibers) in food and is helpful in understanding how the body breaks down carbohydrates. Even if a particular food contains fat or other constituents which subsidize to the total rise in the blood glucose, these consequences are not mirrored in the glycemic index.

Foods with a low glycemic index rate have the tendency to discharge glucose slowly and regularly while foods with high glycemic index release glucose swiftly.

Low glycemic index foods stimulate weight loss and are preferred by people with pre or full blown diabetes. Their bodies produce insufficient insulin quantities (which aids in processing the sugar) and, as a consequence, they are likely to have a surplus of blood sugar. Having a slow and constant glucose release, from the low-glycemic foods, aids in maintaining the blood sugar regulated.

When it comes to foods that are high on the glycemic index scale, they are mostly recommended to counteract insufficient or hypoglycemia. They are often used by individuals to help with the energy recovery after high efforts as long distance running.

How is it calculated?

The glycemic index of food concept was developed in 1980-1981, at the University of Toronto, by Dr. David Jenkins and team, in their research aimed at finding out the best diet for diabetes patients.

They have defined GI as the additional range below the two-hour blood response curve, following a 12 hours fasting period, of food with an indeed available quantity of available carbohydrate (most often 50g). The two hours blood response curve of the processed food is then divided by the one of the standard chosen (usually glucose or white bread) and multiplied by 100. Both the processed food and the standard sample must contain the same amount of carbohydrate. If white bread is the standard and equals 100 then in the same reference glucose is approximately 140.

Well, quite a complicated view, isn’t it? No worries, most important aspects you need to know when creating the perfect diet is (given glucose as standard and equals 100):

Low GI Food= 55 or less
Medium GI Food= 56-69
High GI Food = 70 and above

Top 8 lowest glycemic index foods

1. Fructose

Frequently recommended for individuals with diabetes as it does not provoke the production of insulin by pancreatic cells, fructose is a highly controversial food. It has a glycemic index of 19(reported to the standard of 100 given to glucose) and is reported to be 73% sweeter than sucrose (which has a glycemic index of 68) if consumed at room temperature thus having the advantage of a higher effect in a very low dosage.

There have been studies which have proven the fact that, if consumed before a meal, fructose can lower the glycemic response to the food.

Beverages and food manufactured with glucose or sucrose trigger a much higher rise in the blood sugar than fructose-sweetened ones, however, unreasonable usage of fructose plays a huge part in the development of the nonalcoholic fatty liver disease.

2. Beans

Seen by specialists as the perfect food to boost the glycemic control, beans have a low glycemic index which varies from 27 up to 42( reported to glucose). A proper consumption of beans may well boost the intake of dietary fiber, a crucial aspect in controlling the blood sugar.

Bean type GI( reported to glucose)
Kidney beans 27
Dried beans 29
Butter beans 31
Chick peas 33
Pinto beans 39
Baked beans, canned 40
Blacked eyed peas 42

Some specialists also see kidney beans as one of the world’s healthiest food. Their name comes from the shape they have and are available throughout the year, being especially good in stew dishes as they absorb flavors from all other ingredients.

Best consumed:

To speed up cooking time for kidney beans and make them much easier to digest, it is recommended to presoak them. Make sure that, before cooking the beans, regardless of the pre-soaking method, you drain the soaking liquid and thoroughly rinse them with water.[2]

3. Cucumber

Ever heard of the phrase “cool as a cucumber”? Well, it is used to describe an individual with the ability to stay calm under pressure. As it has the glycemic index of 15(reported to 100 for glucose), cucumber has an extremely slow speed to release glucose in your blood, helping you keep your blood sugar “cool” and under control.

Cucumbers are extremely healthy vegetables, regardless of the glycemic index they have and are a must in one’s diet. They are suitable to be eaten on their own or in salads as they have a mild, fresh taste and have the benefit of not excessively boost your caloric absorption if they are consumed in large amounts. It has even been proven that the body consumes more calories in preparing, eating, digesting and eliminating cucumbers than the food itself delivers to your body thus they are also called one of the “negative calories foods”.

4. Avocado

Researchers say that avocados are one of the foods that, even if eaten in large quantities, they are unlikely to have a compelling effect on blood glucose.

1-ounce of avocado( ~ 28 g) contains only 3 grams of carbohydrates from which 2 grams are taken by the fibers thus leaving less than 1 gram of carbohydrates to be broken down and affect blood sugar.

Although in order to have the avocado register on the glycemic index chart more than 25 grams of carbohydrates are required, it has recently been calculated that the glycemic index of avocado can be approximated to 10 ( reporting to 100 for glucose).

While they do have a low glycemic index, avocados have the ability to raise the fat and calorie counts if eaten in large amounts.
Avocados are also a source of Folate, a vitamin essential for a pregnant woman and of vitamin B36 which is of particular importance in fetal brain development during pregnancy. [3]

5. Olives

Containing very few carbohydrates for all of the species (green or ripe olives) it is widely known that olives have a low glycemic index and are low in calories.

For 100 grams of olives( 3,5 oz), you will have 3 grams of carbohydrates and 2 grams of fiber. Just as for avocado, this will end in only 1 gram of carbohydrates left to be broken down into sugar. The glycemic index is approximated for them at 15.

Olives are an excellent snack choice as they are high in anti-oxidants and anti-inflammatory nutrients. They are a low source of sugar thus can provide you with constant energy without raising blood sugar
The fat contained by olives is monosaturated fat thus heart-healthy fat which can help reduce inflammation and lower cholesterol.[4]

6. Radish

The radish is a root vegetable with colors from white to pink, red or even black which a firm texture when fresh. Although it is usually consumed cooked, it can also be eaten raw.

For 116 grams of radish human body receives 19 calories, 0,79 grams of protein, 0,12 grams of total fat, 3,94 of carbohydrates, 1,9 grams of fiber and 2,16 of sugar. It also provides 19% of Vitamin C. Low amount of carbohydrates leads to a low glycemic index evaluated at 15.

Its content of antioxidants, antibacterial and antimicrobial proprieties are a great asset in boosting up overall health.

7. Mushrooms

Asides from being delicious, mushrooms have been proven through time to have great medicinal powers. Recent studies have shown that specific types of mushrooms have compounds which can help control the levels of blood glucose.

For 121 grams of mushrooms, you get approximately 6 grams of carbohydrates and 3 grams of Dietary fibers. When calculating glycemic index reported to glucose, mushrooms reach a value of 15.
The natural compounds of the mushroom which have been proven to aid the prevention of diabetes have the ability to constrain the absorption of glucose.

Numerous medical studies have demonstrated the fact that mushrooms can help reduce the risks of heart diseases, cancer or even assist in weight control process.

8. Broccoli

Our parents know what they were talking about when they were telling us to eat our broccoli. It has an immense health benefit potential and an enormous impact on our body’s detoxification.

For 148 grams of broccoli, you will get 8 grams of carbohydrates from which 3 grams dietary fibers. The glycemic index is approximated to 15.
It has been proved that broccoli has a significant effect in cancer prevention, reduction of cholesterol, detoxification maintaining heart health and eye health along with great aids to digestion.

Nutritionists recommend steaming broccoli before eating it and avoid as much as possible boiling it as it will lose most of its nutrients. [5]

Top 8 highest glycemic index foods

1. Corn syrup

I need to start by letting you know that Corn syrup and high fructose corn syrup are two different things. Corn syrup is a food syrup made from corn (starch of maize) which contains various amounts of maltose. Also know as glucose syrup it is used by confectioners to soften texture, enhance flavor and retain moisture.

For 100 grams of corn syrup, you will receive a total of 78 grams of carbohydrates, yes; you have read that right! One would imagine that from those 78 grams there are at least some fibers, but no, 0 grams of fiber but 78 grams of sugar is contained in those carbohydrates. No wonder that corn syrup has been evaluated to have a glycemic index of 115( where glucose is 100). [6]

2. Maltodextrin

Some specialist defines maltodextrin more as a sophisticated group of sugars than a carbohydrate, depending on the production method.
100 grams of maltodextrin contains up to 95 grams of carbohydrates of which all 95 are sugars. The glycemic index is evaluated between 85 to 105, depending on exact composition( reported to 100 for glucose).
Mostly popular among bodybuilders after intense workouts it needs to be administrated with caution as it can create a load on the glucose sugar regulatory mechanism.

3. Potatoes ( starch, oven cooked, fried)

One would consider potatoes as a reasonably healthy choice of food, compared to processed food. However, it is an entirely wrong perspective. Potatoes have a huge effect on the blood sugar levels.

Boiled potatoes have a glycemic index of 82 while instant mashed potatoes have a glycemic index of 85. Sweet potatoes are within mode acceptable levels reaching 70.

Often criticized for the sodium and fats contained, potato chips have the lowest glycemic index of them all reaching 51 compared to 100 in glucose.

Precooking the potatoes and eating them cold or reheated should lower the glycemic index of the potatoes consumed.

4. Rice

It has been proven that both brown and white rice have high glycemic indexes, even if, indeed, brown rice is slightly lower.
For 100 grams of white rice, your body will get almost 28 grams of carbohydrates from which 0,4 grams of fiber. It is approximated that rice has the glycemic index of 75.

5. Watermelon

Juicy and tasty food, perfect for cooling during the summer, watermelon provides potassium, vitamins A and C but is also a high source of carbohydrates thus is high on the glycemic index table.

¾ of a cup serving of watermelon is evaluated at the glycemic index of 72 ~ 75.

Consuming a moderate portion of the watermelon should be harmless.

6. Parsnip

Parsnips are root vegetables from the same family as carrots but with the double amount of carbohydrates compared to their relatives.
Believe it or not, a parsnip has an almost same glycemic index as glucose ~ 97. One medium parsnip containing 21 grams of carbohydrates and only 6 grams of fiber.[7]

7. Sports drinks

As sports drinks are created to raise energy after hard workouts, it is only normal that they have a high glycemic index due to the mixture of carbohydrates and electrolytes.

It has been evaluating that sports drinks have a glycemic index of 75 however it depends on from one type to another.

8. Corn flakes

Corn flakes are one of the most popular breakfast food usually served with milk and sugar. They are also used in cooking in various recipes, replacing bread crumbs.

For a quantity of 100 grams of corn flakes, our body receives 84 grams of carbohydrates from which only 3 grams are dietary fiber thus ending up in an approximate glycemic index of 85 compared to glucose as a standard with 100.

How to keep your glycemic index under control during the day

Limitations of using glycemic index foods in elaborating diets

The main limitation of the glycemic index is the fact that it does not evaluate the insulin production caused by blood glucose boost. It is possible that two or more ailments have the same glycemic index but generates different amounts of insulin.

There also exist foods, like steak, which has no carbohydrates, however, has a very high protein volume from which almost 50% it converted to glucose if no carbohydrates are consumed with it.

The glycemic index also varies for the same food due to ripeness, cooking method or variety.

Another limitation of the glycemic index is caused by the different body response from one individual to another, according to the blood glucose levels already existing or resistance to insulin. Also, the glycemic index is calculated on the impact the food has on the individual after two hours since ingestion. However, some diabetes individuals have a response after four hours.

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