The truth about carbs - bad or not?

Carbs are often associated with bread, pasta and potatoes, but they’re found in fruits and veges too – and they’re not all bad for us.

Carbs are often associated with bread, pasta and potatoes, but they’re found in fruits and veges too – and they’re not all bad for us.

Carbohydrates are not universally bad, say experts, despite a rise in the popular lowcarb keto diet.

Carbohydrates, found in bread, potatoes, pasta and sugar (including fruits and vegetables), provide our bodies with glucose which fuels our cells.

Protein and fat can also provide a limited amount of glucose aswell as other sources of energy that can be used by most of our cells.

However our brains like to run on glucose.

The keto diet is popular because it’s based on the theory that if you don’t eat enough carbohydrates tomake the glucose that your brain needs then it willmake something called ketones from fat.

The brain can use ketones as an alternative energy source when desperate. This process is called ketosis.

When ketone levels rise because carbohydrate intakes are very low, appetite tends to reduce and people eat less. And with less carbohydrate blood glucose levels tend to be more stable.

There is also some evidence that peoplewith conditions like epilepsy may benefit from keto eating.

A study in Nature journal published in January 2022 found that peoplewith epilepsy on a keto diet had less seizures.

This is because the keto diet reduces the amount of glutamate, which is a cell that links to glucose burning, in the brain. As a result, neurotransmitters in the brain that cause epilepsy are not as active making it less likely for a seizure to occur.

An average person eats between 150 grams to 200g carbohydrates a day, says Dr Lisa Te Morenga, associate professor atMassey University, but those following a strict keto dietwould reduce their carbohydrate intake to between 20g to 50g a day and eat more oils, fat and protein instead.

With the keto diet, there is no limit to the amount of fat and protein one eats because of those appetite effects.

The keto diet is pretty hard to stick to, though, and most dieters eventually go back to their regular eating patterns, including more carbohydrates. Most people regain all the weight they lost and some even put on more weight than they originally lost.

We don’t have to cut carbohydrates in our diet to be healthy or to lose weight though, says registered dietitian and senior lecturer at University of Auckland, Dr Andrea Braakhuis.

But some carbohydrate foods are better than others, so nutrition experts say we should be thinking more about what types of carbohydrates we are eating.

Eating wholegrains – such as beans, pulses, lentils and legumes – that contain fibre and carbohydrate – ismuch better for our health than sugar, Braakhuis says.

These types of carbohydrates help us feel fuller for longer and themainstay of the healthiest, longest-living populations in the world.

The general diet rule that nutritionists can agree on, though, comes from Michael Pollan. He says: ‘‘Eat food. Not too much. Mostly plants.’’

❚ Reporting disclosure statement:

This story was written with expert advice from registered dietitian and senior lecturer at University of Auckland, Dr Andrea Braakhuis, and reviewed by The Whole Truth: TeMāramatanga expert panelmember Dr Lisa Te Morenga.