DOCTORS and dietitians encourage us to eat carbohydrates as part of a healthy diet while various weight-loss gurus tell people to avoid them. While many of us are happy to eat bread and pasta, for others they’ve become a dietary demon and low-carb and no-carb diets remain firmly in fashion.
Gwyneth Paltrow recently poured fuel on the fire by admitting she doesn’t give her children carbs.
You may think a carb-rich diet means one filled with cakes and stodgy white bread yet carbohydrates are not all created equal. Whole grains, fruit and vegetables are a good source of carbohydrates and they’re also present in milk and dairy products.
Here is our guide to this essential part of the daily diet.
WHAT ARE CARBS?
Carbohydrates are made up of chains of sugar molecules. Glucose and fructose for instance have just one sugar molecule which is why they’re called monosaccharides. Starch, with more than nine, is a polysaccharide.
The fewer sugar molecules there are, the more quickly the carbohydrate is broken down during digestion.
At this point all carbohydrates except fibre are broken down into single sugar units which are absorbed into the blood.
These sugars are essential: glucose is the main source of energy for all the cellular activity in our bodies and the only source of energy for the brain.
When we eat carbs our blood sugar level increases. This stimulates the release of the hormone insulin which in turn stimulates the uptake of glucose from the bloodstream into cells.
Any glucose that isn’t needed immediately is stored as glycogen in our liver and muscles.
Liver glycogen can be converted back into glucose to keep blood glucose levels steady between meals, while the glycogen in muscles provides a source of energy when required.
WILL THEY MAKE ME FAT?
Consuming more calories than we need is what makes us gain weight rather than where they come from.
“Carbs are our friends,” says nutritionist Juliette Kellow. “Especially if we’re dieting because they’re less energy dense than fat.
“If we choose wholegrain or ‘brown’ ones which come packaged with fibre they help us to feel full too.
“However many carb-rich foods such as cakes, chocolate, crisps and biscuits also contain a lot of fat and therefore a lot of calories.
“Processed carbs including sugary cereals and white bread, rice and pasta, are stripped of vitamins, minerals and fibre so are less satisfying than wholegrain varieties.”
WHY DO WHOLE GRAINS MATTER?
Whole grains contain all parts of the grain: the germ, endosperm and bran.
When grains are milled or refined the germ and bran are extracted removing a large amount of nutrients and fibre.
That’s why products made from these refined carbs are sometimes called “processed” carbs. Milling whole grains to make wholegrain or wholemeal flour means none of the goodness of the grain is lost.
They provide carbohydrates, fibre, protein, B vitamins, minerals, plant-based antioxidant phytochemicals and are low in fat. Eating three servings a day has been linked with lower blood cholesterol and a reduced risk of heart disease.
A diet rich in whole grains can also reduce the chances of a stroke, bowel cancer, asthma and gum disease and lower blood pressure.
IS THE GLYCAEMIC INDEX IMPORTANT?
The glycaemic index (GI) is a scale from 0-100 that measures the rate of digestion and the body’s glycaemic or blood glucose response to foods.
GI is a good indicator of the foods to keep blood sugar levels stable. The GI of a food is affected by many things such as the types of fibre, fat and starch it contains and size of the particles. “Low-GI foods (under 55) are digested more slowly so our blood glucose rises accordingly and stays high for longer,” says Azmina Govindji from the British Dietetic Association.
“This helps us to feel full and keeps our mood and energy levels more stable.”
SHOULD I AVOID ATKINS?
Ever since the Atkins diet became famed for its weight-loss credentials, low-carbohydrate, high-protein diets have remained popular.
Yet they have contributed to the current carb confusion. “Before Atkins people believed weight loss came from high-fibre, low-fat diets,” says Azmina.
Robert Atkins claimed by limiting carbs the body switches from using glucose for energy to using energy from fat stores, causing weight loss in a process called ketosis.
“The diet did work because it was very low in calories. There’s some argument to say protein fills you up so you’re less likely to overeat,” Azmina adds.
“Yet essentially if you cut out a whole food group such as carbs you’re restricting your calories.
“However it’s also a dull way to eat and not easy to sustain so people put the weight back on.
“Very low-carb diets don’t leave room for fruit, vegetables and whole grains, essential components of a balanced diet.
“If weight loss is your goal cut down on or eliminate foods that you know are not healthy choices such as fatty and sugary processed foods and reduce your overall portion sizes.
“It can help to have slightly fewer carbs: a quarter of your plate rather than a third.
“Also be discerning about the carbs you eat and favour low GI and wholegrain carbs over high GI and white.”