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

Exploring Carbohydrates

Introduction

I'm going to do a series of blog posts about carbohydrates; what they are and why they are important, how they relate to other sources of energy, their effects on diet and body sculpting and the relative nutritional values of various kinds of carbohydrates.  By which I mean: what are they and which ones are "best"?

What Are Carbohydrates?

The "science": carbs are organic compounds consisting of carbon, hydrogen and oxygen (elements they have in common with protein and fat; protein has an added element of nitrogen and fat has a much higher proportion of carbon to its makeup).


Almost every meal with have some carbohydrate element, but the most accessible form of carbohydrate for us to see are sugars.  There are plenty of other examples of carbohydrates, the more complex types are most commonly found in foods derived from grains (eg flour and rice) and potatoes.  

As part of the digestive process, all carbohydrates are converted to glucose in order to be absorbed by the blood - how quickly we feel hungry is can be related to how quickly our body can convert carbs to glucose, absorb and store the glucose.

Incidentally, dietary fiber is actually an indigestible for of carbohydrate - the bacteria in our gut use them for energy.  Therefore, the energy content of fiber is never included in calorie calculations.

In later posts I'll compare the nutritional values of food sources such as potatoes, rice, bread and pasta.

How Are Carbohydrates Used?

Critically, carbs are the body's preferred source of energy, generally more accessible than fat, being stored in in the muscle that's working and requiring only a short time to be prepared for use as fuel.

Carbs are the brain's only source of energy, although the brain stores its carb reserve in the liver - which the muscles can raid if they need to.  When blood sugar levels get low we get feelings of dizziness and nausea.

Energy Content of Carbohydrates

The nutritional professionals use a few rough and ready numbers for calculating the energy content of food:

• Protein - 4KCals
• Fat - 9KCals
• Alcohol - 7KCal
• Carbohydrate - 4KCal

Next Time...

I'll compare the energy content of various common kinds of "complex" carbohydrates

Weighing on your mind?

The problem with any weight loss strategy is that you cannot stop eating!

Obviously, this can cause problems when dieting, when trying to lose weight through never use or using a combination of the two. Often people over-compensate for the energy expended during exercise by eating too much ("I've earned this"). Many people also drink energy drinks while exercising - these are fatal to weight loss as they almost certainly have a calorie content greater than the energy expended and the calories ingested wont register on the brain's feeding centre … as a result you may feel even hungrier after exercise and drinking these sugary drinks than simply on exercise alone as they can spike insulin levels.

Many people become discouraged with weight loss if it doesn't happen quickly. Others abandon the process after losing a lot of weight initially and the plateauing. Those that do best are those that work to a gradual, sustainable weight management programme and gradually make behavioural changes.

That is why I partner with a professional counsellor to tackle the psychological aspects of diet and weight management to help tackle the mind as well as the body.