Glycemic Index Versus Glycemic Load


Like many people, I need to lose some weight, especially from around my middle.  You could say I have the “middle age spread”, but I’ve had an ample body most of my life.  I lost a lot of weight over the last few years only to start gaining some back over the past 12 months.  After two emergency abdominal surgeries in 2011, I was pretty thin and in poor shape.  In  examining my calories, I ate about 1400-1800 calories a day, which isn’t bad for a 5’11” woman, but my weight was going up, up, up!  It was so distressing to see my thinner clothes starting to get too tight – I panicked!  How could I gain weight on that many calories!  I should be losing weight, not gaining!  Since the problem wasn’t the number of calories I was eating, it must be what I was eating.

I track my food using an app on my iPhone, so it was easy to go back and compare my diet now to what I ate 2 years ago.  It was soon obvious that the make-up of my meals had changed drastically.  I went from eating a low carb,  high protein diet to a low protein, high carb diet!  In addition to the high carbs, I was eating a lot of processed foods and processed fats.

What to do? What to do?  I wanted to be healthy and eat a more natural diet that was based on real foods. From my intro post, you’ll see that I tried a vegetarian diet only to pack on the pounds BY THE DAY!  Wow.  I cannot be a vegetarian.  It made sense to change back to what worked on the past – a lower carb diet with more protein.  But what is low carb?  Does it mean no carb?  What about fruits and veges?  They are carb foods and it doesn’t make sense to not include them in my diet.  Fruits and veges are loaded with important nutrition and fiber.

As a Registered Nurse and former Certified Diabetes Educator, I am well aware of the concept of “Glycemic Index” or GI.  GI is a measure of how much your blood glucose (sugar) level will rise after eating a food.  Glucose, the most basic form of sugar, has a GI = 100.  Other foods will have a GI of less than that, unless they are made from pure sugar.   Food can have a high, medium or low GI (table from Wikipedia, not my usual source of information but it is a good table):

Classification GI range Examples
Low GI 55 or less most fruits and vegetables; legumes; some whole, intact grains; nuts; tagatose; fructose; kidney beans; beets; chickpeas
Medium GI 56–69 whole wheat products, pita bread, basmati rice, grapes, sucrose, raisins, pumpernickel bread, cranberry juice, regular ice cream
High GI 70 and above white bread, most white rices, corn flakes, extruded breakfast cereals, glucose, maltose, maltodextrins, white potato, pretzels

Foods with a high GI raise blood glucose rapidly and cause a sudden release of insulin, which can cause a blood glucose crash later and hunger.  Foods lower on the GI scale raise blood glucose at a slower rate and provide sustained energy, which hopefully means you do not need to eat as often.  This is a pretty simple explanation and my intent is not to give a scientific lecture.  You can read more details here.

Glycemic Load (GL) is based on the Glycemic Index (GI), with an adjustment made for serving size.  For example, oil popped popcorn with butter is a high GI food with a score of 72.  If I was basing my diet solely on the GI index I would avoid popcorn.  The GL of 1 cup of oil popped popcorn with butter is only 3.  So while the popcorn has a high GI, the Glycemic Load is low if you account for serving size.  The key is serving size – if I chose to eat 10 cups of popcorn, the GI remains the same at 72, but the  GL increases to 34, which is high.  You have to control your servings of carb based foods.

This means that on my Glucose Load diet I can enjoy a snack of popcorn popped in oil with butter and still lose weight.  If I went solely by the Glucose Index,  I would not be able to eat popcorn at all.  And who doesn’t want a bowl of popcorn on a family movie night?

Another example is candy.   Lifesavers are all sugar, so they have a GI of 100.  But…if you only eat one, the Glucose Load is 20. Now, I can’t eat just one Lifesaver but if you want to quickly freshen your breath or have a little sweetie, then a lifesaver or 2 isn’t going to blow your diet.  Here is a table that shows glycemic index, load and serving size of many foods.

Like most low carb diets, animal proteins and fats are permitted without restriction.  Meat, cheese, and eggs have a GL of zero since they do not contain carbs.   But I still think one needs to be sensible.  No one needs to eat unlimited amounts of any food, including meat and cheese – although I could live on cheese alone!

According to Rob Thompson, author of The Glycemic Load Diet, you do not need to count calories or carbs or fat grams on a GL diet.  You should focus on keeping your total GL for the day at below 500 and get some kind of aerobic exercise 4 days a week for 30 minutes.   I do not have this book, but I do have his cookbook and the front section has a good description of  how the diet works.  Plus it has some great recipes for low GL foods and even how to use flour substitutes to make crackers and some breads.  You should avoid starchy solids and liquid sugars.  This weekend I’m going to try to make cheese crackers (my weakness) using ground sunflower seeds instead of flour.   I’ll keep you posted on how this turns out!

The Glycemic-Load Diet Cookbook: 150 Recipes to Help You Lose Weight and Reverse Insulin Resistance

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