Carbohydrates: are low-carb diets healthy? (2024)

Carbs can be controversial, but do you need to avoid them? Senior Dietitian Victoria Taylor explains what carbohydrates are, why we need them and what a low carb diet means.

What are carbohydrates?

Carbohydrates or ‘carbs’ are often given a bad press. Aside from the fact that there are no “bad” foods in moderation, it’s not really fair to treat all carbs as the same. The reality is that there are different types of carbohydrates – sugars, starch and fibre– and these have different effects on our health.

There are carbohydrates in most of the foods we eat. But when we talk about carbohydrates, we usually mean starchy foods and sugary foods. Starchy foods, like pasta, rice, potatoes and bread, should make up just over a third of our diet. Sugary foods, such as sugary drinks, biscuits and cakes, don’t need to be included in a healthy diet - but many of us eat them regularly, and it’s ok to enjoy them in small amounts.

Why do we need carbohydrates?

Carbs give us energy. In a healthy balanced diet, most of our energy comes from wholegrain and high-fibre starchy carbohydrates, like oats, wholegrain bread or pasta, brown rice, and new potatoes (with skins on). All carbohydrates break down to glucose, which the body uses for energy, but starchy carbs provide a slower release of energy than sugars because they are larger molecules which take longer to break down. So that’s better for keeping us well fuelled for our daily activities.

The fibre in wholegrain and high fibre starchy foods can help prevent constipation and maintain a healthy gut – and gut health is increasingly understood to be important to our overall health. Research has also shown a link between diets high in fibre and a lower risk of heart and circulatory disease, type 2 diabetesand bowel cancer.

Most people in the UK don’t eat as much fibre as is recommended to benefit our health, so swapping to wholegrain versions of bread, rice, cereals and pasta is an easy step towards better health. The type of soluble fibre in oats has also been found to help reduce cholesterol levels, so porridge or no-added-sugar muesli are a great way to start the day. Wholegrain and high-fibre starchy carbohydrates also provide B vitamins, folate, zinc and magnesium.

Are carbohydrates good for you?

Although carbohydrate foods can be good for us, surveys show that we’re not making the healthiest choices when it comes to the type we’re eating. Most of us are eating too much sugar – which can contribute to a high calorie diet and therefore weight gain. So instead of cakes, biscuits, sugary drinks and sweets, choose healthier snacks like fruit and veg or low-fat plain yoghurt. Fruit and dairy products do contain sugars, but these foods offer other benefits such as fibre or protein as well as a range of vitamins and minerals.

Are low-carb diets healthy and how many carbs should I eat in a day?

Low-carbohydrate diets have grown in popularity for losing weight. They are also used by people with type 2 diabetes to help manage blood sugar levels. A low-carbohydrate diet with 130g (4 ½ oz) or less of total carbohydrate per day has been shown to be safe and effective in the short term for weight loss and diabetes control. However, it doesn’t suit everyone and hasn’t been shown to be better long-term than other approaches, such as a Mediterranean-style diet, so think about what will suit you best. If you are keen to try a low-carbohydrate diet you’ll need to look at all the foods you eat that provide carbohydrates, not just sugary and starchy foods. To give you an idea:

• A medium slice of wholemeal bread or a medium apple both contain around 15g (½ oz) of carbohydrate.
• Half a pint of milk contains 13g (½ oz) of carbohydrate.
• A 50g bar of chocolate contains around 30g (1oz) of carbohydrate.

Because carbohydrates are in so many foods, you’ll need to plan your diet carefully to make sure you get all the food groups you need for a healthy balance of nutrients and enough fibre. If you do have diabetes, you should discuss any changes to your eating habits with the health professionals who are helping you to manage it. If you’re taking any medication which could increase the chances of you having low blood glucose, this might need to be monitored more carefully or be adjusted.

Why are carbohydrates important?

Carbohydrates provide us with important nutrients, and don’t need to be cut out of our diets. Reducing carbohydrates can be a useful strategy for some people trying to lose weight or manage type 2 diabetes. Choosing wholegrain, high-fibre starchy carbohydrates and cutting down on sugary foods will help you to have a healthy digestive system as well as looking after your heart health.

First published 16 June 2021

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