Dieting Basics 1: Carbohydrate confusion – are they good or bad?

What are carbohydrates?

We need glucose for energy, and carbohydrates are the easiest nutrient for our bodies break down into glucose. They also contain fewer calories than protein and fat, weight for weight (3.75 calories per gram.)

There are two main types of carbohydrates:

Simple carbohydrates or Sugar (the “bad carbs”)

These are sometimes called “simple sugars” or “refined carbohydrates”. They’re quickly broken down into energy by your body, as they consist of only two molecules (two glucose molecules with one link between them). Your body only needs to break this one link to turn the food into energy.

Sugars can be divided further:

Monosaccharide (one molecule) sugars which include glucose and fructose (fruit sugar). Glucose, also known as dextrose, and sucrose have the highest GI ratings, meaning that they’ll give you a surge of quick energy – later followed by a slump which may leave you hungry again.

Disaccharide (two molecule) sugars include sucrose (a glucose and fructose molecule joined together), lactose (milk sugar) and maltose (in malt products, such as Shreddies and other breakfast cereals).

Sucrose is often considered the worst type of sugar, nutritionally, and seen as “empty calories”. Like fructose, it’s found in plants – mainly sugar cane.

Fructose is found naturally in fruits, and most nutritionists agree this is fine. Fruits should be eaten generously as part of a healthy diet – they contain lots of goodies like vitamins, as well as fibre to keep you full for longer. However, if you’re in the US, fructose is often used as a cheap sweetener (it’s derived from corn and often known as “high fructose corn syrup) – be careful to check labels, as many nutritionists have raised concerns about high levels of fructose in this form.

Some people are intolerant to lactose, and nutritionists may recommend cutting down on milk products.

If you’re about to run a marathon, row the Boat Race or swim the channel, stuffing a few mars bars into your mouth is a good thing: you get an instant energy surge. However, for those of us whose daily activity mostly involves typing, wiggling a mouse occasionally, and yawning … simple carbohydrates should be eaten sparingly.

If you want to avoid sucrose, go easy on the obvious culprits such as:

  • Sugary drinks (coke, lemonade, sweet wines, alcopops)
  • Cakes, pastries, doughnuts, biscuits, cookies, chocolate bars…

And check labels on the foods you buy: some, like cereals and baked beans, can contain surprising amounts of sugar.

Complex carbohydrates or Starch (the “good carbs”)

image from BBC schools website

Also known as “unrefined carbohydrates” or “starchy carbohydrates”, complex carbohydrates consist of long chains of glucose molecules. Your body takes longer to break these down to digest the food, which means starches are also known as “slow release” carbohydrates that provide lasting energy. You won’t get the instant surge that chocolate delivers, but you will have consistent energy to last you until your next meal.

Starchy foods include pasta, potatoes, rice and flour. “Refined” carbohydrates are ones where part of the grain has been used (for example, the outside of the wheat grain is stripped off to make white flour for using in white bread and pasta). Wholegrains contain more dietary fibre which has numerous health benefits. They also release energy more slowly than refined carbohydrates, and keep you full for longer. These foods have a low-GI rating, meaning they won’t make your blood sugar levels spike.

So, are carbs good or bad?

Although carbohydrates are not essential in order to live (the body can break down protein for energy), most healthy eating guidelines recommend 55-60% carbohydrate. It’s definitely better to go for starches instead of sugars, and to eat wholegrain versions at least some of the time! Wholemeal or granary bread, wholemeal pasta and brown flour are the best options.

Your body is generally good at regulating the amount of glucose in your blood, using insulin – if you have diabetes, or other conditions that affect your insulin production (women suffering from PCOS can also have problems), then consult your doctor as you may need to help your body regulate your glucose levels through careful eating habits.

As a rule of thumb, eat refined sugars in moderation, and base each meal around wholegrain carbohydrates.

(Image above by fuzuoko)


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