Good carbs, bad carbs: what’s the difference?

If you’ve paid any attention to nutrition advice, social media or diet trends in recent years, you could be forgiven for thinking carbohydrates should be avoided at all costs.

Once, fat was the dietary villain. Now carbs are blamed for weight gain, blood sugar spikes, food cravings and a host of health problems. Low-carb and keto diets have added to the idea that cutting bread, pasta, potatoes and other carbohydrate-rich foods is one of the best things you can do for your health.

But are carbs really the enemy? The short answer is no. The longer answer is that not all carbohydrates are created equal — and lumping them all together means some highly nutritious foods get caught in the crossfire.

The truth about carbs

Carbohydrates are one of the three main macronutrients in our diet, alongside protein and fat. They include sugars, starches and fibre and are found in a huge range of foods.

When we eat many types of carbohydrate, the body breaks them down into glucose, which is used for energy. Carbohydrates are an important fuel source for the body, including the brain and muscles.

But the type of carbohydrate matters.

Carbohydrate-rich foods such as wholegrains, legumes, fruit and vegetables come with other useful nutrients. Depending on the food, these can include fibre, vitamins, minerals, protein and beneficial plant compounds.

Fibre is actually a type of carbohydrate — and unlike many other carbohydrates, it isn’t fully broken down and absorbed by the body. It helps keep our digestive system healthy, feeds beneficial gut bacteria and can play a role in managing cholesterol and blood sugar levels. You can read more about why fibre matters in our blog on fibre here.  

The way carbohydrate foods affect blood sugar also varies. Highly refined foods and drinks that are low in fibre can be digested quickly, leading to a faster rise in blood glucose. Higher-fibre foods are generally digested more slowly, and what you eat alongside them matters too.

This is why a bowl of wholegrain oats with nuts, seeds, yoghurt and berries is very different from a sugary soft drink, even though both contain carbohydrates.

Carbs are not inherently fattening either. Weight gain is influenced by overall energy intake over time, along with a range of other factors. However, some highly processed foods are very easy to eat in large amounts and not particularly filling, which can make it easier to consume more energy than your body needs.

So rather than asking whether a food contains carbs, a better question is: what kind of food are those carbs coming from?

Choose more of these carbs

The healthiest carbohydrate foods tend to be whole or minimally processed and rich in fibre. Good options include:

• Wholegrains. Oats, barley, brown rice, quinoa and wholegrain breads and cereals provide carbohydrate along with fibre and a range of nutrients. When choosing packaged foods, check the ingredients list and nutrition panel — “multigrain” or brown-looking bread isn’t always wholegrain.
• Legumes. Lentils, chickpeas, beans and peas are nutritional overachievers, providing complex carbohydrates, fibre, plant protein, vitamins and minerals. They are also relatively inexpensive and easy to add to soups, salads, curries and casseroles.
• Fruit. Yes, fruit contains natural sugars. It also provides fibre, vitamins, minerals and other beneficial plant compounds. Whole fruit is a very different proposition from lollies or a sugary drink. My favourites are berries and kiwi fruit, these fruits are a great source of fibre, vitamins, minerals but low sugar.
• Vegetables. Potatoes, kūmara, corn and peas are sometimes avoided because they are higher in carbohydrate than leafy greens and other non-starchy vegetables. But they can still be part of a healthy diet and provide valuable nutrients and fibre, particularly when eaten with their skins where appropriate.
• High-fibre breakfast cereals. Look for options based on wholegrains, nuts, seeds and other minimally processed ingredients, and check the nutrition information for fibre and added sugar. Look for cereals that are mostly wholefoods and contain ingredients you recognise or could have in your pantry at home. Te Atatū Toasted mueslis, for example, provide at least 5g of fibre per serve from ingredients including wholegrains, nuts, seeds and lentils.

Carbs to eat less often

You don’t need to ban these foods or feel guilty when you eat them. But they are generally best enjoyed less often, particularly when they make up a large part of your diet.

• Sugary drinks. Soft drinks, energy drinks and other drinks high in added sugar can deliver a large amount of carbohydrate very quickly, with little or no fibre to slow digestion.
• Lollies and confectionery. These are typically high in added sugar and offer little in the way of fibre or other nutrients.
• Cakes, biscuits and pastries. As well as refined carbohydrates and added sugar, many are high in fat, making them energy-dense and easy to overeat.
• Highly sweetened breakfast cereals. Some cereals contain significant amounts of added sugar and little fibre. Check the nutrition panel rather than relying on claims on the front of the packet.
• Highly refined grain foods. White bread, many crackers and other foods made from refined grains are often lower in fibre than wholegrain alternatives. That doesn’t make them forbidden foods, but choosing wholegrain options more often is an easy way to improve the quality of the carbohydrates you eat.

The bottom line? Carbs are not the enemy.

Rather than cutting out an entire food group, focus on where your carbohydrates are coming from. Choose wholegrains, legumes, fruit and vegetables more often, look for foods that provide plenty of fibre, and eat highly refined and sugary options less frequently.

Because when it comes to carbs, quality matters.