Carbohydrates and Diet

Introduction

Leading in from my current series of posts on complex carbs...

Over a cup of tea, a friend just said “I need a sugar fix”.  That got me thinking: sugar is addictive.  People are “called” to it as with any other addiction.

The problem is, as with many addictions, the fix is short lived and can cause more problems than it resolves.  Primarily, if the sugar isn't immediately required by the body (ie you’re not exercising), it spikes the insulin response, which causes the body to store sugar in the blood stream in muscles and liver as glycogen, or as fat in the flabby areas around the body (problem 1).  However, whilst eating the sugary food, you do get an immediate and very satisfying mini “high”: sweets called comfort foods for a very good reason.  Sweet.

Following that, the body suddenly finds the initial promise of boundless energy is not sustained: expecting a gradual tail-off of the supply of sugar which can be managed, there’s a sudden drop.  Leading to a down swing in mood and energy – and often a return to hunger.

Glycemic Index

The glycemic index relates to how quickly sugar in foods is absorbed into the blood; it was originally devised to assist diabetics with managing their blood sugar levels by observing how quickly certain foods caused an insulin spike - this insulin spike has been associated with a return to feeling hungry shortly after consuming sweet foods (as I mentioned above).

Some dieters have found that choosing food based on its glycemic index can help them combat hunger pangs and make dieting easier: the bottom line with weight loss is a reduction in calorie intake - obviously, if you're not always ravenously hungry, losing weight is much easier!

Note that the glycemic index of food is an average based on observing how quickly the blood sugar rises after consumption: the numbers you see quoted are therefore not absolutes but only indications of the relative speed of absorption.  For reference, glucose has an average glycemic index of 100, but has been observed to have an index as low as 85 and as high as 111.  Food combinations can also change the glycemic index - consuming glucose with fibre brings the index range down to somewhere between 57-85 - in line with the observation that fibre helps keep you feeling full for longer.

Glycemic Load

The index relates to the rate of absorption into the body, the glycemic load is the product of the number of calories and the glycemic index and is a better indication of the what kind of insulin spike might be caused by consuming food.

There's a table at the end of the article ordered by glycemic load (once -again based on 100g of the food item) predictably, foods with the highest calorific value tend to be towards the top of the table ... however, a normal baked potato moves from near the bottom of the table to the middle and sweet potatoes move from the middle to the bottom!

OK, as I mentioned, everything in the tables has been based on 100g rather than the vague notion of "a portion" ... but practically speaking, what's in a portion?

I have two measures to hand: a baked potato (500g) and a slice of wholegrain bread (50g) ... that means that the glycemic load of the potato is actually 94.9 while two slices of bread is only 69.7 ... the baked potato would therefore be more likely to cause an insulin spike and you'd be more likely to feel hungry later!

Food	Glycaemic Index	Glycaemic Load
Egg Noodles	70	49.7
White Bread	70	37.8
Brown Bread	65	33
Wholegrain Bread	69	69.7
White Rice	60	27
Potato	70	18.9
White Pasta	55	17
Brown Rice	50	11.5
Brown Pasta	39	10.3
Sweet Potato	20	8.2

One of the sources I used to research this was http://www.glycemicindex.com/, some of the values are slightly different: remember, glycemic indexing isn't an exact science