low glycemic v. low carb

Question
Can you explain the difference to me?
I have a friend that lost weight on low carb,she doesnt eat pasta or noodles or ice cream -on the low glycemic index,these are OK!.
On the low gly

Answer
Hello, Bud,
I can explain the difference between "low carb" and "low glycemic", but I would like to correct one thing first.  Pasta, noodles and ice cream are not low glycemic.  They can be specially designed to be, with low glycemic sweeteners or by using grains other than wheat.  At best these may be low glycemic load if you ate just a very, very small amount of them.  "Glycemic load" is the combination of glycemic index with the portion of the food.  This will be clearer later.

Carbs' link to weight gain has led to a lot of confusion, with more and more definitions and nuanced methods to allow people to find a healthful diet that has a limited effect on blood glucose.  High blood glucose leads to insulin secretion spiking, which turns on your body's fat storage reaction.  In the end, this is what it is all about.  Glucose in your blood stimulates your pancreas to make insulin, which then grabs glucose molecules and brings them into cells to be used for energy.  And, if insulin is really spiking, your body will sense that there is extra energy and start up fat storage.  Without an insulin spike, there is no fat storage and hence the use of low carb and low glycemic diets to lose weight.  

"Glycemic index" is a scientific measurement used to rank the effect of various foods on blood glucose.  A person eats an amount of food that contains a particular weight of carbohydrates, say 100 grams, and then their blood glucose is measured.  The result is compared to the effect of eating a fixed amount of pure glucose, here 100 grams.  Glucose is the sugar that your body uses for energy and is what carbohydrates are eventually broken down into.  Thus, in glycemic index (GI) measurements, the amount of carbohydrate is fixed, but the *kind* of carbohydrates present in the food varies and is what is ranked relative to glucose.  The glycemic index has been very useful, but as people became more familiar with it, they started to see its limitations.  The most obvious one was that you don't eat 100 grams of carbohydrate worth of every kind of food.  Some foods you eat more of than others (think carrots vs potato chips).  For example carrots and watermelon are high glycemic (GI) but low glycemic load (GL) - ie. when eaten in their normal portions, they do not have the effect expected from being high glycemic.  No one is going to eat that many carrots at a sitting, and watermelon is filled with water so a big piece has fewer carbs than you would expect.

Now, for "low carb".  "Low carb" really refers to a diet strategy, not a scientific measurement like glycemic index.  When low carbing, you keep it easy by simply counting carbs and keeping the total number of grams of them low, to a degree you choose.  In general, strict is no more than 10 grams a day, with a graduation up to maybe 50 grams a day (which is considered by many to be an upper limit).  All the GI, GL, good/bad and every other nuance is irrelevant to a strict low carber.  But as you go up to say South Beach level of carbs, dieters can have freedom to pick and choose.  The same as with dieters eating low glycemic but not counting carbs necessarily.  The strictest low carb is the most reliable to lose weight and is the easiest to know you are sticking to.  It requires more discipline and motivation since it is the hardest to stick to and offers the least freedom.  However, with "less strict" variations, you must be sure you understand the true impact of the carbs you are eating, and make doubly sure you just don't keep sliding along adding more and more "okay" things until you are barely on a diet.  

I know this is really "grey" as far as defining "low carb" vs "low glycemic".  But the reality is is that at this point, there are many ways to classify carbs for dieting purposes.  The way I think about them is the following:  "Low glycemic" is a rank order of foods used to help people manage their carbs to lose weight.  Low glycemic dieters may or may not count the total grams of carbs eaten through the day.  "Low carb" is a strategy, promoted by Atkins and others, where the dieter counts carbs and limits the total number of grams of carbs eaten each day.  The foods may or may not be low glycemic (although low GI may be preferred).  http://www.glycemicindex.com/ is a good site to learn about GI if you are interested.

Well, hopefully all this answered your question.  If it didn't, please write back and I will try to do better.  

Sincerely,
Arlene

1. Prev:I always feel sleepy
2. Next:Enzyme supplement