The Glycemic Index is a measure of how foods that are high in carbohydrates raise blood glucose. The standard for this ranking system is pure glucose, or white bread. Foods with high GI raise glucose levels in our blood more than foods with a low GI. Foods that are Low on the GI index have a GI score of 55 or less. Medium is 56-69. High is 70 or more.
Glycemic Index History
The (GI) Index was conceived by David Jenkins and other researchers in 1981 at the University of Toronto as part of a type 1 diabetes study. The specific goal was to test the impact of different carbohydrates on blood sugar levels as compared to glucose. Since its creation and distribution, it has been debated how effective the index is at helping people make healthier decisions about nutrition. I am among the believers that sugar, carbohydrates, and blood glucose levels affect our health. Like many others however, I am still on the fence about the viability of basing decisions on the GI Index.
How is the score determined
Fat and fiber lower the GI of a food. Greater complexity in cooking, or processing the ingredients of a food raise the GI score (though exceptions exist.) Ripeness, storage time, and variety can also affect the GI value. The primary metrics when calculating the score are the Cooking Method, Processing Method, Type of Starch, Fiber, Sugar, Fat, and Acidity. The score is measured based on average change in blood sugar levels during a 2 hour interval after consuming the food item in question. Foods that are quickly digested have higher GI scores due to fast and dramatic blood sugar response. Carbohydrates that are slowly digested have a lower GI score. This means that a food can have a low GI score, and still carry a lot of carbohydrates through our bodies. One way to think of the GI score is as a “quick burn assessment.” Because it does not emphasize long-term effects of foods on the carbohydrate cycle; it may not be the best source of information for the physical aspects of weight-loss etc. It does however shed some light on short term, or psychological effects of foods and our desires about the food in question. The urge to eat something is likely related to blood glucose spikes in our physiologies. Basically it means that frequent ingestion of foods that are high on the GI scale may have a similar effect as having infrequent foods that are low on the index, but still high in carbohydrates. It could also be that infrequent ingestion of foods that are high on the GI scale have a negligible effect on weight loss (though unlikely.) Quantities of the comparative foods would most likely have an impact on our desired health benefits from making decision on the GI index, but studies are not as thorough as we would like them to be and are not able to shed much light on these differences and likenesses. Some foods are even excluded from being on the list because of their high GI scores. Examples of seemingly unfair assessments are: whole wheat bread having similar GI score as white bread though it contains more fiber, and phytochemicals. One of the greatest criticisms of the method points to a lack of documented satiation and hunger effects as a result of eating food. Conclusion: do not solely base your consumption decisions based on the GI Index. Take other factors into consideration. I think the GI Index is a valuable tool in my decision making process, but not worthy of being the only tool. My personal experience is that a general rule of eating low/no carb, high fat/oil (the healthy kind,) high protein, and high fiber foods is good for me. These principles seem to mostly mimic the trends in the GI Index tables.
Topics Worth Considering when Researching GI Food Values
Eating low GI foods is reportedly good for weight loss, increased energy, improved mood, diabetes, heart disease, blood pressure, cholesterol, triglycerides, inflammation, gallbladder disease, and breast cancer. Some of these are backed by studies, others are self proclaimed by those who enjoy a lifestyle with low GI foods. If our diets can control all these thing, (and possibly others,) it means that we are capable on some level of being much healthier as a species by making better eating decisions.
Some books worth looking up regarding the GI Index are: The New Sugar Busters, Dr. Atkins New Diet Revolution, The Zone, The South Beach Diet, and The New Glucose Revolution. After perusing the database with all GI Values being sorted from smallest to largest GI score, I was surprised to find 409 items to have a value of zero most of which were raw or cooked meat. Upon closer assessment I saw some interesting foods in that category that I thought I would share with you. Most notable to me were: Vodka, Sugar-Free Root Beer, Margarine-like spread, “Bacon grease or meat drippings,” and an entry defined as “Meat NFS.” For those of you who may not know what NFS means, it stands for Not Further Specified. To entertain myself I did a search of the entire list for the word butter which yielded no results. Though not all aspects of this study seem credible or relevant to all the health related areas media-hype would make it out to be. There are some phenomenal studies being done for sure. One such study is the European MRC Human Nutrition Research study that strives to include European Ethnic Foods to include; Czech, Danish, Dutch, German, and UK specific foods. This study expands the search parameters to include English names and original spelling from their original languages. Also interesting is the Harvard Health GI website that lists only 2 items with a GI Index score under 10 including Hummus (30 grams) and Peanuts (50 grams). Perhaps they do not want to advocate the health benefits of Vodka and Bacon Grease for liability reasons.
In summary, the GI Index scale is not a perfect system for the general public. It definitely has specific applications to science, health, and associated industries. It is not necessarily a great tool for general assessment and decision making when making important decisions about nutrition, diet, and specific health related goals. Make sure to “take the information with a grain of salt,” (pun intended: while searching for salt, sodium, and baking soda; I did not find any of those, but I did notice that Baklava had a much lower GI score than Saltine Crackers.) Do not discredit the information completely. It most certainly can help in our decision making processes but is not meant to be the sole source of information when making decisions about these important matters. Look into specific foods on the list more thoroughly and continue to make good consumption decisions.
- Healthy, Happy, Body, Mind, Heart
http://preventcancer.aicr.org/site/DocServer/Glycemic_Index.pdf?docID=341
www.mendosa.com/GI_GL_Carb_data.xls
http://www.glycemicindex.com/foodSearch.php
http://appliedresearch.cancer.gov/glycemic_db/
http://appliedresearch.cancer.gov/DHQ/database/gi_values.csfii_94-96_foodcodes.csv
http://appliedresearch.cancer.gov/DHQ/database/dhq1.gi.d092304.csv
http://www.mrc-hnr.cam.ac.uk/research/research-sections/nutrition-health-interventions/gi-database/
http://dietdatabase.com/glycemic-index-and-glycemic-load/
http://www.health.harvard.edu/diseases-and-conditions/glycemic_index_and_glycemic_load_for_100_foods
Glycemic Index History
The (GI) Index was conceived by David Jenkins and other researchers in 1981 at the University of Toronto as part of a type 1 diabetes study. The specific goal was to test the impact of different carbohydrates on blood sugar levels as compared to glucose. Since its creation and distribution, it has been debated how effective the index is at helping people make healthier decisions about nutrition. I am among the believers that sugar, carbohydrates, and blood glucose levels affect our health. Like many others however, I am still on the fence about the viability of basing decisions on the GI Index.
How is the score determined
Fat and fiber lower the GI of a food. Greater complexity in cooking, or processing the ingredients of a food raise the GI score (though exceptions exist.) Ripeness, storage time, and variety can also affect the GI value. The primary metrics when calculating the score are the Cooking Method, Processing Method, Type of Starch, Fiber, Sugar, Fat, and Acidity. The score is measured based on average change in blood sugar levels during a 2 hour interval after consuming the food item in question. Foods that are quickly digested have higher GI scores due to fast and dramatic blood sugar response. Carbohydrates that are slowly digested have a lower GI score. This means that a food can have a low GI score, and still carry a lot of carbohydrates through our bodies. One way to think of the GI score is as a “quick burn assessment.” Because it does not emphasize long-term effects of foods on the carbohydrate cycle; it may not be the best source of information for the physical aspects of weight-loss etc. It does however shed some light on short term, or psychological effects of foods and our desires about the food in question. The urge to eat something is likely related to blood glucose spikes in our physiologies. Basically it means that frequent ingestion of foods that are high on the GI scale may have a similar effect as having infrequent foods that are low on the index, but still high in carbohydrates. It could also be that infrequent ingestion of foods that are high on the GI scale have a negligible effect on weight loss (though unlikely.) Quantities of the comparative foods would most likely have an impact on our desired health benefits from making decision on the GI index, but studies are not as thorough as we would like them to be and are not able to shed much light on these differences and likenesses. Some foods are even excluded from being on the list because of their high GI scores. Examples of seemingly unfair assessments are: whole wheat bread having similar GI score as white bread though it contains more fiber, and phytochemicals. One of the greatest criticisms of the method points to a lack of documented satiation and hunger effects as a result of eating food. Conclusion: do not solely base your consumption decisions based on the GI Index. Take other factors into consideration. I think the GI Index is a valuable tool in my decision making process, but not worthy of being the only tool. My personal experience is that a general rule of eating low/no carb, high fat/oil (the healthy kind,) high protein, and high fiber foods is good for me. These principles seem to mostly mimic the trends in the GI Index tables.
Topics Worth Considering when Researching GI Food Values
Eating low GI foods is reportedly good for weight loss, increased energy, improved mood, diabetes, heart disease, blood pressure, cholesterol, triglycerides, inflammation, gallbladder disease, and breast cancer. Some of these are backed by studies, others are self proclaimed by those who enjoy a lifestyle with low GI foods. If our diets can control all these thing, (and possibly others,) it means that we are capable on some level of being much healthier as a species by making better eating decisions.
Some books worth looking up regarding the GI Index are: The New Sugar Busters, Dr. Atkins New Diet Revolution, The Zone, The South Beach Diet, and The New Glucose Revolution. After perusing the database with all GI Values being sorted from smallest to largest GI score, I was surprised to find 409 items to have a value of zero most of which were raw or cooked meat. Upon closer assessment I saw some interesting foods in that category that I thought I would share with you. Most notable to me were: Vodka, Sugar-Free Root Beer, Margarine-like spread, “Bacon grease or meat drippings,” and an entry defined as “Meat NFS.” For those of you who may not know what NFS means, it stands for Not Further Specified. To entertain myself I did a search of the entire list for the word butter which yielded no results. Though not all aspects of this study seem credible or relevant to all the health related areas media-hype would make it out to be. There are some phenomenal studies being done for sure. One such study is the European MRC Human Nutrition Research study that strives to include European Ethnic Foods to include; Czech, Danish, Dutch, German, and UK specific foods. This study expands the search parameters to include English names and original spelling from their original languages. Also interesting is the Harvard Health GI website that lists only 2 items with a GI Index score under 10 including Hummus (30 grams) and Peanuts (50 grams). Perhaps they do not want to advocate the health benefits of Vodka and Bacon Grease for liability reasons.
In summary, the GI Index scale is not a perfect system for the general public. It definitely has specific applications to science, health, and associated industries. It is not necessarily a great tool for general assessment and decision making when making important decisions about nutrition, diet, and specific health related goals. Make sure to “take the information with a grain of salt,” (pun intended: while searching for salt, sodium, and baking soda; I did not find any of those, but I did notice that Baklava had a much lower GI score than Saltine Crackers.) Do not discredit the information completely. It most certainly can help in our decision making processes but is not meant to be the sole source of information when making decisions about these important matters. Look into specific foods on the list more thoroughly and continue to make good consumption decisions.
- Healthy, Happy, Body, Mind, Heart
http://preventcancer.aicr.org/site/DocServer/Glycemic_Index.pdf?docID=341
www.mendosa.com/GI_GL_Carb_data.xls
http://www.glycemicindex.com/foodSearch.php
http://appliedresearch.cancer.gov/glycemic_db/
http://appliedresearch.cancer.gov/DHQ/database/gi_values.csfii_94-96_foodcodes.csv
http://appliedresearch.cancer.gov/DHQ/database/dhq1.gi.d092304.csv
http://www.mrc-hnr.cam.ac.uk/research/research-sections/nutrition-health-interventions/gi-database/
http://dietdatabase.com/glycemic-index-and-glycemic-load/
http://www.health.harvard.edu/diseases-and-conditions/glycemic_index_and_glycemic_load_for_100_foods
