What is the Glycemic Index?

When making food choices, it may be helpful to avoid foods that have a high glycemic index (GI). The GI is a ranking system from 0 to 100 for carbohydrate-rich foods (sugars and starches) based on how much they raise blood sugar levels compared to glucose, which has a GI ranking of 100.  Upon eating carbohydrates, the glucose from the food breaks down during digestion and gives your body energy.  The GI measures how much our blood glucose (sugar) spikes in the two or three hours after eating a carbohydrate.  The speed at which food is able to increase your blood glucose level is called the "glycemic response".

If you have gained and lost weight over many years, are clinically obese, have diabetes or pre-diabetes or food cravings, then you may want to pay close attention to this index and learn to avoid eating foods that are high on the glycemic index, which are believed to spike your blood sugar.  You may eat them in small amounts, when eating with protein after you have reached your healthy weight goals (assuming you are not allergic or senisitive to the particular food).  If you are not losing weight quickly enough or if you are stuck in your weight loss, you should carefully consider the foods you are eating and compare them to the GI index to make sure that you are not eating high GI foods.

The GI ranks carbohydrate-rich foods according to their glycemic response.  Carbohydrates that break down rapidly during digestion and raise your blood glucose levels quickly, such as the baked potato (Russet), white rice, white bread, and corn flakes have a higher GI rating versus foods that tend to raise your blood glucose levels more steady and slowly, such as the sweet potato or yam, parboiled or converted rise, pumpernickel bread, and All Bran^TM.  Based on the GI if you want to eat a potato, red skin potatoes are better than brown skin potatoes, but sweet potatoes are even better as they are a low GI food and are high in fibre.  Foods that are high in fat or protein do not cause our blood glucose to change significantly.

Currently, scientists have measured the glycemic indexes of about 750 high-carbohydrate foods. Generally speaking, the lower the GI rating, the better the quality of the carbohydrate.  Low GI ranked foods tend to be all-around healthier choices as they are usually lower in calories and fat, while also higher in fibre, nutrients, and antioxidants.  According to the Canadian Diabetes Association, "choosing low GI foods more frequently may help you increase levels of HDL (healthy) cholesterol in your blood and might also help to control your appetite, as they tend to keep you feeling fuller, longer".

Benefits of Low GI Foods

The reason it is important to be mindful of the GI is because eating carbohydrates (carbs) that are rated with a high GI can cause our blood glucose to quickly spike and then crash downward.  The body produces insulin to re-balance the blood sugar.  Blood glucose spikes can cause a sudden boost in energy, which is then followed by a downward crash that can often result in symptoms such as tiredness, headache, irritability and food cravings for more carbs.  When your body crashes from carbs it sends false messages to the brain that say "feed me", but you actually crave more carbs because it has been trained that carbs react quickly and raise the blood sugar.  Your body then gets into a vicious cycle where your blood sugar spikes and crashes all day long.  It is this spike and crash cycle of high glycemic foods that causes weight gain and loss of blood sugar control.

In addition to controlling your blood glucose level, eating foods with a low to medium GI can provide other benefits such as:

• Controling your cholesterol level
• Controling your appetite
• Lowering your risk of getting heart disease
• Lowering your risk of getting type 2 diabetes

Make Wise Food Choices

In summary, you should try to choose foods that have a low to medium GI rating.  If you are trying to lose weight, then you should avoid completely high GI foods.  Once you are in maintenance mode you can gradually add into your diet limited quantities of high GI foods, but these should be consumed in conjunction with a minimum of 1 ounce of protein.  To be effective, protein should follow the consumption of a carb within 15 to 20 minutes.  Keep in mind that carbohydrates spike blood glucose levels and proteins level them out.  Excess sugar in the body is stored as fat.

It is possible to predict what the GI of a food might be from what it looks or tastes like.  Food that is overcooked increases its GI; therefore it is best to eat pasta al dente (firm) and to not overcook foods such as oatmeal.  The following Glycemic Index Chart provides a brief list of low, medium and high GI foods.  A GI of 55 or less ranks as low, a GI of 56 to 69 ranks as medium, and a GI of 70 and above ranks as high.

The Glycemic Index Controversy

While there are many in the medical community that advocate the use of the glycemic index, there are also many that question its merit.  One such individual is University of Virginia professor, Glenn Gaesser, who has recently done considerable research and analysis in the area of diet programs, carbohydrates and the glycemic index, and the body weight index.  Based on his research, Gaesser believes that the glycemic index, which is used by many popular diet programs, is not a reliable description of the quality of a carbohydrate.  Gaesser's studies show that  people that who are on high carbohydrate diets tend to be slimmer and even healthier than those individuals who adhere to a low carbohydrate diet.

Gaesser has also researched whether there was any correlation between carbohydrate consumption and diseases such as cancer, heart disease, and type 2 diabetes.  His findings showed that there was no clear link that avoiding high GI carbohydrates in one's diet helps to prevent any of these diseases.  His theory is that if you cut certain foods out of your diet, there is a good chance that you will experience some level of weight loss if you are consuming less calories.  Gaesser believes that a high carbohydrate, low fat diet is the best choice for long term weight management.

The Glycemic Index Chart

Recommended Glycemic Index Food Pyramid Guidelines

• Eat at least 5 portions of vegetables a day.
• Eat 3-6 portions a day of gross bread, grain, pasta and other low glycemic, amyloid foods.
• Eat fruit 2 to 3 times a day.
• Eat nuts, seeds and shell fruits 1 to 3 times a day.
• Eat up to 2 portions a day of pure proteins such as meat, fish, poultry, and eggs. Do not eat red meat more than 1 to 2 times daily.
• RARELY eat white bread, rice, potatoes, and sweets such as cookies and cakes.

Sample Low GI Foods Menu Guide

The following provides a Sample Low GI Menu Guide for losing weight based on low GI foods. These are only examples, so please feel free to mix and match any of these food items. You can also change the food (as long as you use low or fat free and no sugar added), but it is best to use the amounts suggested. It is important that you include protein in every meal and snack.

Please note that you should always check with your medical doctor before making drastic diet changes.

BREAKFAST (within 1 hour of waking):

• 1 whole egg mixed with Egg Beater^TM to equal 2 eggs
• 3 strips of Turkey Bacon
• 1 slice of Spelt Bread (has less than 1 gram of carb) toast with low fat spread or "no sugar" added jelly

SNACK MEAL:

• 1 container of low fat, no sugar added yogurt or Cottage Cheese
• 1/2 apple, 1/2 cup berries or any whole fruit

LUNCH:

• Sandwich made with 1 to 2 ounces of low fat ham or turkey, lettuce, tomato, and low fat mayonnaise or mustard OR a salad with 2 ounces of sliced chicken, ham, and/or turkey, hard boiled egg, and 1 ounce cheese. You can use any kind of dressing that you want as long as it is served on the side. Stick the tines of the fork in the dressing, then fill your fork with salad.

SNACK MEAL:

• 4 ounces Cottage Cheese
• 20 green grapes, 10-15 walnuts, pecans, or almonds

DINNER:

• 3 ounces baked or broiled chicken, fish, or beef
• 1/2 cup steamed vegetables
• small side salad (use dressing on the side just like at lunch)

SNACK MEAL (only if you are hungry before bed:

• 1 serving of soy crisps