I recall my mother-in-law describing the 300 pounds of potatoes they picked up each fall to help nourish her growing family of 4 kids over the winter. Nowadays you'll hear of people who've sworn off potatoes, won't touch baby carrots and steer clear of bananas. What do these things have in common? They all have a high glycemic index meaning they trigger a quick rise in blood sugar. Now before you tune out and discount this as yet another incidence of good food "turned bad", lets look a little closer at glycemic index. The glycemic index (GI) is a measure of how quickly a food enters your bloodstream. When a food raises blood sugar quickly it triggers the hormone insulin. The result is often a quick rise in energy and then a rapid drop in blood sugar leaving you feeling tired and possibly hungry again. If you routinely choose high glycemic foods you may have trouble controlling your hunger, maintaining your energy and even managing your weight. You end up on a roller coaster of blood sugars leaving you susceptible to sugar cravings and over eating. Does this mean you should stop eating all high GI foods including carrots, potatoes and bananas? Not necessarily. There are some times when high GI foods can be beneficial such as during and after endurance exercise. Glycemic index is just one factor in food selection. You should not exclude or include a food solely on the merits of it's glycemic Index. For example dark chocolate has a much lower glycemic index than cooked carrots or potatoes. If you serve a side dish of Smarties with dinner tonight, I'm sure your kids will be delighted however you would be using the GI incorrectly. The carrots and potatoes provide a great source of vitamin A and fibre among other nutrients. The candy provides mainly sugar and fats. It's a good idea to understand how GI is measured to truly evaluate how your body will respond to certain foods. A sample group of people are fed 50 grams of a test food and their blood sugar response is measured and averaged. The important point to note is that they are fed a test food in quantities equal to 50 grams of digestible carbohydrate. In order to get 50 grams of digestible carbohydrate from carrots you have to eat 1.5 pounds as compared to only 3oz of chocolate! It's no wonder the carrot eaters had a high glycemic response, that's a lot of carrots. If you ask me, the chocolate test group got a much better deal. The bottom line is, carrots are still in the good books if you eat them in reasonable portions. When you factor portion into the equation this is called Glycemic Load. For more information on Glycemic Load click here http://diabetes.about.com/library/mendosagi/ngilists.htm Regardless of quantity, you may be wondering why carrots have a faster GI than chocolate.
The rate at which a food is digested and absorbed is affected by many factors. All of the following affect GI: fat, fibre, processing, cooking, acidity as well as type of starch and sugar. The added fat and type of sugar in chocolate slows down it's absorption. Other sweets such as Lifesavers and jelly beans are all low in fat and consequently have a high GI. This is another reason why low fat foods are not necessarily better for you. Is your head spinning? I don't recommend studying tables of glycemic index on a daily basis to choose your foods. Think of glycemic index as another colour on your "palate" for painting your picture of health.
Here are some examples of how you can simply adjust your eating using the principals of GI to get longer lasting energy from the foods you choose. The more processed a food the faster the sugars are absorbed. Therefore choose less refined grains such as dense dark breads rather than fluffy white bread. The more you cook a starch the faster it breaks down. Therefore eat your pasta al dente. Portion matters as well. When eating a pasta meal, cut back on the portions of high GI pasta and white bread and be sure to include some lower GI vegetables such as salad or mixed veggies. This helps to lower the "glycemic load" of the meal. Very ripe fruit has a higher GI therefore buy your bananas with some green. Adding acid with a meal can slow digestion and lower GI by 30%. Therefore add some lemon juice to your drink or extra vinegar to a salad when eating potatoes or other high GI foods at a meal. And finally, the type of starch can make a big difference in GI. When choosing potatoes the waxy types will breakdown slowest therefore choose Ontario white and new potatoes for a lower GI. I don't know what kind of potatoes my mother-in-law used some 40 years ago but regardless of their GI she raised a healthy, happy family on a base of wholesome foods.
For more information on Glycemic Index including a table of 750 foods click here: http://diabetes.about.com/library/mendosagi/nmendosagi.htm
For more information on Glycemic Index, carbohydrates and health attend heidi's seminar “Carbohydrate Savvy” on February 26th (519) 824-4120 ext. 53460 or register online in the Events section of this website.
A great cookbook with low GI recipes is:
The Good Carb Cookbook: Secrets of Eating Low on the Glycemic Index by Sandra Woodruff M.S., RD www.penguin.com
For more information on the Glycemic Index register for the upcoming seminar “Carbohydrate Savvy” In our Events section on February 26 or visit our “Tips and Ideas” section for a list of Glycemic Index Links.