The Glycemic Index Diet
What is the glycemic index diet? It is a diet based on the correlation between foods that have carbohydrates and blood sugar levels and release of insulin.
The glycemic index diet is marketed as beneficial for those who suffer from type 2 diabetes, and would most certainly aid in shedding some extra pounds.
The glycemic index (GI) came into existence in the 1980s and became a gadget for diabetics to control spikes in their blood sugar. (1) GI ratings range from 1 t0 100, with 0-55 considered low glycemic, 56-69 in the middle, and 70-100 being considered high glycemic substances.
What does this mean? It means that consumption of foods with high glycemic ratings are more probable to result in spikes in blood sugar for suffers of type 2 diabetes, which heightens the risk of continuing high blood sugar readings. (2)
Biology and Nutrient Composition
Many carbohydrates contain starches, sugars, and fiber. The body is able to break down starches and sugars and turn them into glucose, which powers our cells. Fiber passes through and the body does not digest it.
Two key hormones to control blood sugar are released by the pancreas. Glucose from the blood is moved to cells to utilize for power thanks to Insulin. Glucagon sends for stored glucose in the liver to be let go into the body when blood sugar levels dip.
Foods rich with fiber are most often digested and used more slowly. It is theorized that the more even and measured the speed for release of energy, the more potential good results there can be for regulating the three key parts of health well-being: blood sugar, appetite, and weight control. (3)
Getting to know the GI values of different foods to help you choose what to eat is an alternative method to controlling your consumption of carbs. The technique is meant to assist in the selection of foods that have carbohydrates that will be processed slower, while steering you away from foods that spike your blood sugar. (4)
What you need to take away is that GI values are very beneficial in determining what are “good carbs” and “bad carbs”.
Glycemic Rating
The glycemic index is only applicable to foods that contain carbohydrates. Proteins and fats are not big pieces of the puzzle, however, consumption of fats and protein alongside carbohydrates can affect the blood sugar levels’ response to the carbs. (5)
There are foods out there that contain fats AND carbohydrates, such as seeds and nuts, but the carbohydrate content in these foods are so low that they are often seen as fatty foods.
Consider this: A baked russet potato’s glycemic rating is 111. This food is most likely going to spike blood sugar due to it being well over the top of the GI charts. Garbanzo beans, on the other hand, have a super low glycemic rating of 6. (6) These aren’t the only legumes with pretty low GI values.
A GI rating and a glycemic load (GL) value are different on the basis of serving sizes. Watermelon’s GI value is 80, which would be considered “high”, howevr, one would have to consume a lot of watermelon to reach the amount of digestible carbs it would take to spike their blood sugar, due to watermelon being 92 percent water. (7)
A formula is applied by analysts that can give you a better grasp of your response to a specific food by dealing with the portion size problem. The amount of food that you have consumed will determine the effect it has on your blood sugar levels. If you consume a little more than 4 ounces of watermelon, the GL is 5, which is quite low.
How do you find out if the food you’re eating will actually affect your blood sugar? You have to multiply the GI value by the number of carbohydrates in one serving. Then divide the product by 100. Quotients between 1 and 10 are considered low, medium ranges from 11 to 19, and anything above 20 is considered high.
For instance, a single cake doughnuts contains 23 carbs and has a GI value of 76. You can multiply 76 by 23 and divide the product by 100 to get a GL rating of 17.48. The GL of the cake doughnut is in the higher end of the medium bracket.GL rating of one cake doughnut has 23 carbs and a GI value of 76.
A whole wheat English muffin has a GI of 45; a white wheat English muffin clocks in at 77, so it’s easy to see a single serving of the refined flour product will have a greater impact on blood sugar levels.
There is plenty of information online about glycemic ratings. In fact, the University of Sydney has a facility for GI testing that allows you to search for common foods and get their GI values. (8)
Clinical Trials and Studies
The OmniCarb Randomized Clinical Trial found no hard evidence supporting the notion that consumption of foods with low GI values improved sensitivity to insulin, systolic blood pressure, or levels of cholesterol. (9)
The National Institutes of Health stated that additional studies would be needed to determine long-term effects of glycemic index diets after they reviewed a variety of clinical trials. (10)
The Glycemic Index diet is part of a list of diets that can assist one in managing diabetes; it joins other diets such as the Mediterranean diet, protein-rich diets, and low-carb diets. (11)
A study of GI and GL ratings and how they relate to diet and illness found that many subjects indicated that additional nutritional factors must be linked so that accurate conclusions can be drawn. (12)
Make sure you also take note of our forskolin review which talks about its ability to directly influence glycemic levels as well. We also briefly touch upon this in our post here and here.
There have been no long-term studies of the effect of GI diets made available yet, however a year and half long trial that tracked weight deviations in Brazilian women who subscribed to the diet did not find promising results for being able to prevent weight gain.
Thinking about starting the glycemic index diet? Just be reminded that how you combine options on the menu can lessen the effect of foods that would cause a blood sugar spike. Think about combining high GI foods with proteins, fats, or low GI foods.
You don’t even need to count calories or worry about controlling your portions when using the GI diet. You should keep a handheld device with you when you’re buying food, so that you can see the GI and GL ratings of what you’re about to consume.
References:
- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3058718/
- http://www.everydayhealth.com/hs/type-2-diabetes-live-better-guide/glycemic-loa
- http://health.usnews.com/best-diet/glycemic-index-diet
- http://www.elementsdatabase.com/glycemic_index.php
- http://jn.nutrition.org/content/136/10/2506.full
- http://www.health.harvard.edu/healthy-eating/glycemic_index_and_glycemic_load_for_100_foods
- http://wonderopolis.org/wonder/how-much-water-is-in-a-watermelon
- http://www.glycemicindex.com/
- http://jama.jamanetwork.com/article.aspx?articleid=2040224&resultClick=24
- http://www.ncbi.nlm.nih.gov/pubmed/21280171
- http://www.ncbi.nlm.nih.gov/pubmed/23364002
- http://www.ncbi.nlm.nih.gov/pubmed/17992183