Understanding the Glycemic Index

I agree the glycemic index is one part of the puzzle however it is an important part. The importance of the glycemic index is underscored by its function as a common denominator in many healthy eating plans.

Enter the Zone by Dr. Barry Sears describes a diet which is low glycemic that includes fruit and vegetables emphasizing ‘above ground’ vegetables, and fruits that contain a good amount of fiber. The South Beach which is essentially the Zone with a snob appeal name suggests the same thing. Atkins when you get to the back of the book seems to be on board with low glycemic carbs as well, not to mention the Paleolithic, Mediterranean and others.

Benefits of a low glycemic index diet include:

A low glycemic index diet lowers fasting insulin levels which promotes the ability to burn stored fat and improve body composition. Without lowering fasting insulin, weight loss is almost impossible no matter how much exercise you do or how much you restrict your caloric intake.

Elevated fasting insulin levels are also associated with many chronic diseases such a cardiovascular disease. A low glycemic diet lowers fasting insulin levels.

Elevated fasting insulin also correlated with elevated CRP which is a measure of your total body inflammation. This correlates with diseases such as cardiovascular disease, Alzheimer's disease, diabetes, arthritis, and cancer.

Low fasting insulin also results in greater effectiveness of human growth hormone replacement therapy and higher natural IGF1 levels by allowing higher levels of IGF-1 to be produced by the liver, since high insulin levels may reduce IGF1 production through a negative feedback loop.

Lowering insulin and glucose levels reduces the damage to cellular proteins caused by glycosylation or the binding of excess sugar to cellular proteins as measured by HgA1c. Glycation of proteins, or the sticking of sugar to protein molecules, is thought to be one of the mechanisms of aging.

http://www.antiagingatlanta.com/lowglycemicdiet.htm

The rationale behind low GI diets isn't just about the insulin reaction caused by blood sugar spikes that might lead to fat coversion.
Moderate GI diets are full of slow release foods that keep you feeling full for longer. I find it useful to stave off hunger, lightheadedness, tiredness and weakness between meals and I'm neither dieting nor diabetic.

However, even this runs into some problems in practice. Potatoes, for instance, being high GI, should be digested quickly and leave us feeling empty soon, right? However, in some tests, when volunteers were asked to eat boiled potatoes and then their feeling of fullness monitored over the next 2 hours, the volunteers felt very full compared to other foods. http://www.mendosa.com/satiety.htm

Again, another instance of the folly of looking only to GI to guide your food choices.

The other rationale for caring about GI is that the more insulin resistant you are, the more that a rise in blood sugar leads to food cravings. The theory is that your body pumps out more insulin to try and get the glucose into cells, and your brain reacts to the raised insulin levels by trying to get more sugar.

I don't know how sound the science is, but I know the feeling of being full and craving more food. So it seems plausible to me.

But you're right, GI values are based on foods on their own, and when you start looking at them in combination with other foods (or how they are prepared), the impact can be very different.

Another problem with GI is that it doesn't factor in how many carbs are in the food. This is why carrots have a high GI...but the serving size you have to eat to really get an impact is huge. So they've come up with a better concept called the glycemic load, which factors in both the blood sugar response and the amount of carbs.

See http://vanderbiltowc.wellsource.com/dh/content.asp?ID=655 for more on the glycemic load and this http://ziag4.mmb.usyd.edu.au/mainV4a.htm to look up GL values.

My doctor's office advises this diet to diabetics. I am not the diabetic in the household, but I found out quickly other diabetics in the family don't seem to be advised this way. They took the liberty of disputing this doctor.

Dispute in the diet market place is laughable. It's not so funny to find it in your doctor's office. The doctors that publish diet books somehow don't seem real. To find a real world doctor backing this advice made me read up on both sides. I don't have the formal education to plug any diet, but this might be worth some study.

I read in my "Joy of Cooking" book that potatoes get dried in the sun to strengthen their skin, then placed in cold storage for an unknown period of time. I believe this has to be true or you couldn't have Idaho potatoes in January. The book adds, this processing increases the starch and sugar.

I don't mean to knock America's favorite vegetable, but we are accused of being an obese nation. I'm sure they are not the only culprit, but nearly any diet plan suggests dropping the fries.

How many people are actually using potatoes from the produce department. The frozen, already oiled ones take up the most space in the freezer section of the store. I'm now seeing some advertised that magically get crispy in the microwave. What could make that happen. Then there's the instant ones and potato chips.

It's very good to point out that GI should be evaluated not by individual food item alone, but by overall food combination during a particular meal or snack. Personally, I undertook a glycemic index diet on the advice of my doctor to lower my cholesterol, and it has helped. I have lost 16 pounds over about 6 months of dieting, and I continue to lose -- at a reasonable pace. My doctor stressed to me (and I now stress to others when promoting this style of eating) to evaluate the GI of the entire meal. I still have a portion of a baked potato occasionally, for example, but that potato makes up the smallest portion of my meal.

The person who pointed out that the GI approach nullifies food cravings is right on, too. I'm a chocoholic, but I find when I eat a GI balanced meal or snack, my sugar craving is virtually nonexistent.

Everyone is different, that's why any diet advise only applies to a portion of the population and will cause dispute. Some people's genes have adjusted to the unnaturally high blood sugar levels caused by high fructose corn syrup and procesed grains, some haven't. And response changes as we get older. For people who "tend" to gain weight (both water and fat) and show symptoms (diagnosed or not) of food allergies or hormonal imbalance (hypoglycemia, postprandial reactive hypoglycemia, adrenal abnormalies, whatever), avoiding foods is CRITICAL, not laughable or ridiculous.

Imbalances have mild to drastic symptoms, and many medical studies have proven that over a prolonged period they can and will lead to diabetes and heart disease. Bottom line, people with these symptoms have been cured with this diet, so who cares if the GPs of the world want to ignore it because they can't read a study that is 100% conclusive? The symptoms weren't just in their head. The cure wasn't just in their head. If it walks like a duck, looks like a duck, and sounds like a duck... Who will feel the most stupid when the conclusive study DOES come out, and confirms these links? They sure haven't provided a conclusive study that disproves it yet.

I am on a hypoglycemic diet, and my symptoms have disappeared, and I'm losing the "unexplained" weight gain. And with significant and positive results like that, I can easily afford to ignore any naysayers :) And I'm sure not going to ignore cures until normo-glycemic people and all the doctors, authors, and the Soda, Snack, Sugar, Caffeine, Alcohol, Potato, Bread, and Starch Councils, Lobbies, and PACs agree with any findings.

However the GL index operates it does work. I did the Nutrisystem thing for 5 weeks and in that time I went from 311 lbs to 282 lbs. Went from 49-51 waist to a loose 42. Hunger was never a factor, well kinda at the start for two days or so, but not starving hunger and was easily beat down. I also felt the same as some of the previous comments, as I had more energy, almost had to force myself to eat the lunch meal because I just wasn't hungry. I had set my meals, snacks, etc. in almost equal increments. Like breakfsst @ 0800 hrs, snack at 1100 hrs, lunch @ 1400 hrs, snack @ 1700 hrs, Dinner @ 2000 hrs. Snack @ 2300 hrs, or something to that affect.

I find it much harder though to plan my own GL and make it effective. It has been 7 and 1/2 months since the comlpletion of the Nutrisystem 5 weeks and I have put on approximately 4-5 lbs. I presently go 286 lbs. Some mornings I weigh in at 287-288 lbs, and other mornings I might weigh in at 284-285 Lbs. My waist has stayed the same at a comfortable (not tight or loose) 42 in.

I am not losing anymore weight or inches but I seem to be maintaining a balance. However there is much more weight and inches I need and want to lose but my figuring of the Gl is obviously not the right one. I may go back to the prepared GL so I can reach my goal of 220-225 lbs. and 36-38 inches waise. Oh by the way I am 70 years on this planet and stand 6' 1".

Just my two cents about the GL. Thanks for listening.