Glycemic Index vs. Glycemic Load
If you have been living in low-carb land for a while or just recently started following our fat loss diet, you'll know that keeping your blood sugar under control is the key to weight-management.
If your blood sugar is stable the entire day, it's nearly physiologically impossible for you to to pack on unwanted fat. At the same time, if your blood sugar is stable the entire day and you exercise, it is physiologically impossible for you not to burn fat.
Carbohydrates, especially sugar-based foods and drinks, are overwhelmingly responsible for raising your blood sugar. But not all carbohydrates are the same.
There's two scales for estimating the effects a particular food will have on your blood sugar levels- Glycemic Index and the Glycemic Load.
Although the later is lesser known, Glycemic Load, is a significantly better resource for separating the "good" carbohydrates from the "bad" carbohydrates.
We'll explain why...
What is the Glycemic Index?
The Glycemic Index is a scoring system for foods.
It is based upon how quickly 50g of carbohydrates from a food, will increase your blood glucose levels. Every food is given a score between 0 to 100, based upon how similar that food affects your blood sugar levels when compared to sugar.
For example, 4 slices of white bread = 50g of carbohydrates.
When 4 slices of bread are consumed it raises your blood sugar levels by approximately 73% compared to what sugar does. Therefore white bread has a glycemic index of 73.
Foods with a high Glycemic Index act similar to that of sugar and cause a significant spike in not only blood sugar, but also insulin.
If your goal is to gain a shit load of fat or maybe add a double chin.... then I’d highly recommend you eat plenty of high Glycemic Index foods!
However, if you are looking to lose fat or even just maintain a ripped lean physique, keep reading as I am going to let you in on an easy way to do so.
What is Glycemic Load?
Glycemic Load is also a measure of how much a food will increase a person’s blood glucose levels.
It allows us to rank carbohydrate rich foods based on their overall carbohydrate content per net weight.
Mathematically speaking, Glycemic Load = Glycemic Index X Carbohydrate (g) / 100.
Foods with a...
- Glycemic Load of less than 10 are considered low Glycemic Load foods.
- Glycemic Load between 10 and 20 are considered moderate Glycemic Load foods.
- Glycemic Load over 20 are classed as high Glycemic Load foods.
Foods with a low Glycemic Load have little impact on your blood sugar levels, while high Glycemic Load foods cause a significant spike in your blood sugar.
A spike in blood sugar is quickly followed by a spike in insulin which as we discussed in our article “Why Sugar Makes you Fat” is the quickest way to gain fat!
Interestingly, Glycemic Load was developed by scientist to improve on some of the flaws associated with the Glycemic Index. I’ll talk more about this later.
Why Are They Useful?
Both glycemic index and glycemic load are useful tools.
They both provide us with an easy to understand ranking system for foods containing carbohydrates. See, times have changed and so too has nutrition. Science has come a long way and we know more about diet then we have before. Gone are the days of the low fat and 99% fat free craze.
Because we know a diet high in carbohydrates is a major cause of obesity and we know that carbohydrates are the number one over consumed macro nutrient by most people. Glycemic Index and Glycemic Load are like the modern day version of low fat and 99% fat free. They help identify something important about that food, and that is its impact on your blood sugar levels.
Using the glycemic index and glycemic load tool allows you to conveniently manage your carbohydrate intake and this is critical if you have any hope of losing fat or maintaining a healthy body weight.
The Limitations of the Glycemic Index
Several randomized trials have investigated the use of low glycemic index diets to control blood glucose, however the results have been mixed to say the least.1 Some of these studies have shown significant improvements in post meal blood glucose concentrations and overall glycemic control, with the adherence to a low glycemic index diet.2,3,4,5
However several randomized trials have not shown significant improvements in glycemic control.6,7,8
This is because glycemic index has one flaw... a significant flaw-
It fails to consider the serving size of the food.
Let me explain this through a simple example. See watermelon is considered a high glycemic index food, however although the sugar found in it is quickly digested, watermelon barely contains any of this sugar. In fact you’d have to eat a shit load (782 grams to be precise) of it in order to significantly raise your blood sugar and insulin levels.
Nobody eats 782g of watermelon in one sitting!
Similarly, it works in the opposite manner as well. For example, chocolate is classified as low glycemic index. Suggesting that the sugar found in it is slowly digested. However, this because chocolate contains a lot of fat, which slows the digestion of the sugar, so don't fool yourself- it's not "blood sugar friendly" food.
Go By the Glycemic Load to Lose Fat
Glycemic load is a much better choice for those wanting to lose fat. This is because it DOES take into consideration the amount of carbohydrate contained within the serving of a food. Again, let me best explain this through an example. A baked potato has a glycemic index of 85 while a snickers bar has a GI of 55. However, the average size of a baked potato is about 120 grams and this contains 20g of carbohydrates, while the snickers bar has a serving size of 72g and contains 42g of carbohydrates. Therefore, the glycemic load of the baked potato is 17 and the snickers is 23. Low glycemic load allows you to eat many of the foods you like, but ensures the serving size is restricted to minimize the spike in your blood glucose and insulin levels.
Carbohydrates can be included in a weight loss eating plan, however knowing how much and what types is fundamental to the success of this. Glycemic load provides a simple tool to help you understand what effect particular foods have on your blood sugar levels. This means eating to better regulate your metabolic hormones (insulin and glucose) as this important for anyone wanting to lose fat and gain lean muscle. Using the glycemic load is just one simple way for you to find that balance between your intake of carbohydrates and your desired weight loss
Glycemic Index vs. Glycemic Load
(Easy to Understand Video)
Credit to: Kyle Leon at CustomizedFatLoss.com
Glycemic Load Charts & Resources
- "List of Glycemic Load for Common Foods" by Dr. Anthony Komaroff; Harvard Medical School
- "The Biggest Glycemic Load List Ever" (450+ pages) by David Mendoza
1) Sheard NF, Clark NG, Brand-Miller JC, Franz MJ, Pi-Sunyer FX, Mayer-Davis E, et al. Dietary Carbohydrate (Amount and Type) in the Prevention and Management of Diabetes. Diabetes Care. 2004;27(9):2266-2271.
2) Giacco R, Parillo M, Rivellese AA, Lasorella G, Giacco A, D’Espiscopo L, et al. Long-term dietary treatment with increased amounts of fiber-rich low-glycemic index natural foods improves blood glucose control and reduces the number of hypoglycaemic events in type 1 diabetic patients. Diabetes Care. 2000;23(10):1461-1466.
3) Gilbertson HR, Brand-Miller JC, Thorburn AW, Evans S, Chondros P & Werther GA. The effect of flexible low glycemic index dietary advice versus measured carbohydrate exchange diets on glycemic control in children with type 1 diabetes. Diabetes Care. 2001;24(7):1137-1143.
4) Wolever TM, Jenkins DJ, Josse RG, Wong GS & Lee R. The glycemic index: similarity of values derived in insulin-dependent and non-insulin dependent diabetic patients. J Am Coll Nutr. 1987;6(4):295-305.
5) Brand JC, Colagiuri S, Crossman S, Allen A, Roberts DC & Truswell AS. Low-glycemic index foods improve long term glycemic control in NIDDM. Diabetes Care. 1991;14(2):95-101.
6) Lafrance L, Rabasa-Lhoret R, Poisson D, Ducros F & Chiasson JL. Effects of different glycaemic index foods and dietary fibre intake on glycaemic control in type 1 diabetic patients on intensive insulin therapy. Diabet Med. 1998;15(11):972-978.
7) Luscombe ND, Noakes M & Clifton PM. Diets high and low in glycemic index versus high monounsaturated fat diets: effects on glucose and lipid metabolism in NIDDM. Eur J Clin Nutr. 1999;53(6):473-478.
8) Heilbronn LK, Noakes M & Clifton PM. The effect of high and low glycemic index index energy restricted diets on plasma lipid and glucose profiles in type 2 diabetic subjects with varying glycemic control. J Am Coll Nutr. 2002;21(2):120-127.