Is sugar bad for you? It’s one of the most common nutrition questions, and depending on who you ask, you’ll get very different answers.
So what’s the truth? As with most things in nutrition, the answer sits somewhere in the middle.
The first thing to understand is that sugar isn’t inherently bad. In fact, your body runs on it. Every time you eat a bowl of porridge, a baked potato, some beans, a banana or a slice of bread, your body breaks those carbohydrates down into glucose – a simple sugar that provides fuel for your muscles, organs and brain.
The problem isn’t that we eat sugar. The problem is that some sources of sugar come packaged with fibre, vitamins, minerals and plant compounds, whilst others come largely on their own. And it turns out that this difference matters a lot.
Sugar is a type of carbohydrate, and carbohydrates are one of the body’s main sources of energy.
Carbohydrates come in many forms, from the sugars found naturally in fruit to the starch in potatoes and whole grains. Although these foods may seem very different, most digestible carbohydrates are eventually broken down into glucose, which can then be used by the body for energy.
This is why carbohydrates have never been the nutritional villain they are sometimes made out to be. In fact, some of the healthiest foods we can eat – fruits, vegetables, beans, lentils and whole grains – are rich in carbohydrates.
One of the biggest misconceptions in nutrition is that sugar is sugar, no matter what form it comes in. Whilst all carbohydrates eventually provide us with glucose, the food they come packaged in makes a huge difference.
Take an apple and a glass of apple juice. Both contain sugar, but each has a very different impact on our body. The apple contains fibre, water and a structure that slows it all down. We have to chew it, it takes time to eat and it fills space in the stomach helping us feel satisfied. The juice contains many of the same sugars, but much of the fibre and structure has been removed. It can be consumed in seconds and is generally far less filling.
The sugar itself hasn’t changed. The food around it has. This is where nutrition gets really interesting. Foods are much more than the sum of their nutrients.
Scientists sometimes refer to this as the food matrix – the structure within which nutrients are packaged. Increasingly, research suggests that the health effects of a food depend not only on the nutrients it contains, but also on how those nutrients are delivered. This helps explain why whole fruit is consistently associated with positive health outcomes, despite containing naturally occurring sugars.
When health organisations talk about limiting sugar, they are generally referring to free sugars.
These include:
They do not include the sugars naturally present within whole fruits and vegetables. This distinction is important.
Few people would sit down and eat six oranges in one go. Yet drinking the juice from six oranges can take less than a minute. The fibre, water and structure of the fruit help regulate how quickly we eat it and how satisfied we feel afterwards.
Sugar itself isn’t toxic. Having a slice of birthday cake, a biscuit with a cup of tea or a dessert after a meal isn’t going to damage your health. The concern arises when large amounts of free sugars become a regular feature of the diet.
It can make it easier to overeat
Foods high in free sugars are often less filling than fibre-rich whole foods. Think about how easy it is to drink a large bottle of cola compared with eating the same number of calories from potatoes, beans or fruit. When foods don’t satisfy our appetite particularly well, it becomes easier to consume more calories than we need.
It can reduce overall diet quality
If sugary drinks, sweets, cakes and highly processed snacks make up a large proportion of our diet, they inevitably take the place of other foods. Over time, this can mean less fibre, fewer vitamins and minerals, and fewer of the plant compounds that support long-term health.
It can increase our preference for sweetness
Humans are naturally wired to enjoy sweet foods. From an evolutionary perspective, sweetness signalled a valuable source of energy.
The challenge is that modern foods can be far sweeter than anything our ancestors would have encountered. When we regularly consume highly sweetened foods and drinks, that level of sweetness becomes our new normal. Fruit and other whole foods can seem less appealing by comparison.
The good news is that taste preferences are surprisingly adaptable. Many people find that when they reduce highly sweetened foods, fruit begins to taste sweeter and they start enjoying flavours they previously overlooked.
It can affect dental health
Bacteria in the mouth feed on sugars and produce acids that gradually damage tooth enamel. The more frequently our teeth are exposed to free sugars throughout the day, the greater the risk of tooth decay.
Blood sugar has become a hot topic on social media, often accompanied by dramatic graphs and warnings about “spikes”.
Don’t believe everything you see. In reality, a rise in blood glucose after eating is completely normal. That’s exactly what our bodies are designed to do.
The difference lies in how quickly food is digested and how satisfying it is. A sugary drink may be absorbed very rapidly and leave you looking for food again soon afterwards. A meal based around beans, vegetables and whole grains comes packaged with fibre, protein and bulk, helping to provide a steadier release of energy and greater fullness between meals.
The solution isn’t to avoid carbohydrates. The solution is to choose carbohydrates that come packaged with fibre as often as possible.
You’ve probably heard sugar being compared to cocaine. I certainly have. Whilst there is no doubt that sweet foods activate reward centres in the brain, the evidence doesn’t support putting sugar in the same category as addictive drugs.
Most experts do not consider sugar to meet the clinical definition of an addictive substance. What we can say is that highly processed foods rich in sugar, fat and salt are often extremely rewarding and very easy to overconsume.
The encouraging news is that our preferences can change. Many people find that when they start eating more fibre-rich whole foods, their cravings for highly sweetened foods gradually become less intense.
Current UK recommendations suggest that free sugars should contribute no more than 5% of our daily energy intake. For adults, this equates to around 30g of free sugars per day.
To put that into context:
Remember that this recommendation applies to free sugars, not the sugars naturally present in whole fruits and vegetables. There is no recommendation to limit whole fruit intake for the general population because of the overwhelming data showing the benefits to our health and wellbeing.
If you’d like to cut back on free sugars, there is no need for a dramatic overhaul. Small changes can make a big difference.
Build meals around whole plant foods
Whole grains, beans, lentils, vegetables and fruit naturally provide carbohydrates alongside fibre and a wealth of beneficial nutrients. If you find that you have intense sugar cravings, starting here may help dampen that overwhelming desire for a sugary treat.
Choose whole fruit more often than fruit juice
Whenever possible, eat your fruit rather than drinking it. You’ll get the same natural sweetness, but in a much more healthful and satisfying package.
Give your taste buds time to adapt
If you regularly add sugar to tea, coffee or breakfast cereals, try reducing it gradually. Many people are surprised by how quickly their palate adjusts.
Read labels occasionally
You don’t need to obsess over every gram of sugar, but becoming aware of where free sugars are hiding can be useful. Breakfast cereals, sauces, yoghurts, smoothies and plant-based drinks can vary considerably.
Yes – but probably not in the way the headlines suggest.
The sugars naturally present in fruits, vegetables, beans and whole grains are not something to fear. These foods are consistently associated with better health outcomes and deserve a regular place on our plates.
Free sugars are a little different. Consuming large amounts can contribute to tooth decay, excess calorie intake and poorer overall diet quality. Rather than focusing on cutting sugar out, focus on what you can add in. More fruit, vegetables, beans and whole grains.
When it comes to sugar, we don’t need to fear it, obsess over it or eliminate it. But we do benefit from understanding where it comes from and how it fits into the bigger picture of our diet. Because good nutrition isn’t built on avoiding a single ingredient. It’s built on the totality of foods we choose day after day, year after year.
Written by Rosemary Martin, RD 2022. Updated 2026.
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