Low to moderate glycemic index carbs produce a small but steady rise in insulin levels (healthy) as opposed to high glycemic index carbs that produce a large and rapid rise in insulin levels (unhealthy).
Low to moderate glycemic index carbohydrates provide slow release of energy that supplies continuous fuel for the body and brain and for the working muscles. Their slow rate of digestion and absorption puts less stress on the insulin producing cells in the pancreas.
Misconceptions about the Glycemic Index abound and people often have a hard time putting the principles into daily dietary practice.
A glycemic rating over 70 is high. Medium runs from 70- 56. Under 55 is considered low.
Many factors affect the glycemic index of a carbohydrate. In general, carbohydrates that are more processed and ground more finely with the bran separated out will have a higher glycemic index.
Guidelines for choosing lower glycemic index breads, cereals, crackers, chips and other carbohydrate packaged products:
Limit your intake of finely ground, soft, puffed and flaky products. Finely ground flour products - both 100% whole wheat and white flour such as soft whole wheat or white flour bread, crackers, breakfast cereals will have a high glycemic index. If you can mush it together and form a ball out of it - the glycemic index is high.
Anything "puffed" such as puffed wheat, rice or corn cereals - even whole wheat ones - usually has a high glycemic index. If something has been processed into small fine particles that can be crushed into crunchy crackers and cereals - the glycemic index is probably going to be high -even those made out of good whole grains. Most crackers, packaged cold cereals and chips have a glycemic index in the 70s, 80s and 90s.
Instead, choose dense, grainy, chewy products. Foods with intact fiber will be more "dense" and chewy and less flaky and light. If the fiber is intact the product will have a lower glycemic index. Grainy, dense breads are more likely to have a lower glycemic index. Choose coarse breads with at least 50% intact kernels.
Sourdough breads, because of the acids produced by the fermentation of their yeast starter culture, have much slower rates of digestion and absorption.
You can also eat whole grains in their natural state. Whole intact grains that have been softened by soaking and cooking will have a low GI value. For example, cooked barley has a GI value of only 25. Cooked whole wheat has a GI value of 41. But choose old fashion whole grains and not the "instant" varieties - any thing that has been "instantized" is probably going to have a higher glycemic index.
Fruits and Vegetables:
Choose barely ripe fruits and vegetables for a lower glycemic index. Overly ripe fruits and vegetables have higher sugar content and a higher glycemic effect than just ripe foods.
Tropical fruits, such as mango, papaya, pineapple, and cantaloupe tend to have higher values than temperate fruits such as apples and oranges. But all fruits are OK. Even the higher glycemic index fruits like pineapple will usually have a GI rating in the 60s. Just don't eat only watermelon (GI 72).
Almost all vegetables are low to moderate glycemic index and are great to eat. The poor carrot has been greatly maligned as having "too much sugar" but actually has an average glycemic index of only 47.
Most potato varieties have a high glycemic index due to the presence of high amounts of amyl pectin that is quickly digested.
Tiny new white and red bliss potatoes have a lower GI value than normal varieties. Russet baked potatoes have the highest glycemic index (an average of 85) and mashed potatoes an average of 92.
The glycemic impact of potatoes can be lessened by eating smaller portions and varying your diet with alternatives such as sweet potato (GI- average 61 - the starch in sweet potatoes is amylose - more slowly digested and absorbed) or yams (GI average 37).
Rice vs. Pasta:
Pasta gets a bad rap. Pasta gets blamed for all sorts of maladies because it routinely gets categorized as a bad carbohydrate. "They" say to cut out the pasta and eat rice.
Well, it just so happens that pasta has a low to moderate glycemic index (30-55) that results in a slow, steady release of energy in your body.
Pasta made with semolina is made from cracked wheat and not finely ground flour so it has a moderate glycemic index. Furthermore, pasta is unique in its physical make up. The reason for its slow digestion and steady release of energy is "the physical entrapment of ungelatinized starch granules in a sponge-like network of protein molecules in the pasta dough." That is something you don't need to understand to get the good news that pasta can be good for your energy. Yippee!
But always serve pasta al dente. If you overcook pasta it gets soft and swollen and you have fully "gelatinized" those starch granules and turned pasta into an energy drainer.
Almost all kinds of pasta have a lower glycemic index than most varieties of rice - even brown rice (a glycemic index over 70 is typical because almost complete "gelatinization" of rice starch takes place during cooking). And pasta has more protein than rice or potatoes. Overall semolina pasta is a good energy food and can be part of a high-energy diet. Remember though - a serving is just 1/2 cup and keep variety in your diet by not eating pasta any more that once every four days.
Rice varieties such as Jasmine and short grain varieties (even short grain brown rice) that have a lot of amylopectin tend to have higher glycemic index GI (high 70s to 139). You will know these higher amylopectin rice varieties because they tend to stick together after cooking (an example of the "if you can mush it into a ball and it sticks test").
High amylose content rice varieties such as Basmati, Uncle Ben's converted rice and long grain brown rice have a low glycemic index. If the rice grains stay separate after cooking it is more likely to have a lower glycemic index (GI 50s and 60s)
Great alternatives to rice include pearled barley, buckwheat, bulgur, couscous, or noodles - all moderate to low GI.
Glycemic Index values can be interpreted intuitively as percentages on an absolute scale and are commonly interpreted as follows:
|Low GI||55 or less||Most fruit and vegetables (except potatoes, watermelon), grainy breads, pasta, legumes/pulses, basmati rice, milk|
|Medium GI||56 - 69||Wheat bread, whole wheat products in general, brown rice, orange sweet potato, table sugar|
|High GI||70 - 99||Corn flakes, baked potato, some white rices (eg. jasmine), croissant, white bread, candy|
Simple steps to lower the glycemic effect of your diet:
To get good glycemic control you don't have to eliminate all high glycemic index foods - just be sure and have at least one low glycemic carbohydrate at each meal.
Overly cooked foods are predigested have higher sugar content and a higher glycemic index. Avoid over cooking your foods.
Fats slow down the digestion of starches. The higher the fat content of a food the lower its glycemic index. This is why the glycemic index of potato chips is lower than that of a baked potato. To lower the glycemic effect of a high glycemic food such as a French baguette add a little fat such as olive oil, good quality organic butter or some nut butter.
When you do eat a high GI index carbohydrate include protein with it. The protein will slow down the rate of digestion and can cut the glycemic index effect by about one third.
The higher the acid content of a food the lower its glycemic index. Acids in foods slow down stomach emptying, thereby slowing the rate at which the starch can be digested. Include some acidic foods in your meals like vinegar, lemon juice, limejuice, some salad dressings, and pickled vegetables.
A side salad with your meal will help to keep blood glucose levels under control. Four teaspoons of vinegar in a salad dressing or about four teaspoons of lemon on your food or in your water reduces the glycemic effect by about one-third.
Include more legumes in your diet. Legumes are super nutritious, high fiber low glycemic index foods (GI ranging from 13 to 59). If you want to ensure stable long lasting blood sugar control legumes are your friends.
The glycemic index is only one of many markers you can use to choose nutritious foods. It is not the only marker to use. Often it is better to have a higher glycemic index food such as baked potato than a lower glycemic index food such as potato chips. Consider not only the glycemic index of a carbohydrate but also the nutrient value of the food when making your choice.
Even with these guidelines it can sometimes be hard to tell the glycemic effect of a carbohydrate. But when you are not carrying a reference book around with you these guidelines will help you take better care of your health and well-being.