Sugar: The Sweet Truth. How Much Do We Actually Need?
Depending on what you read, sugar is responsible for everything from weight gain and diabetes to inflammation, poor energy levels and bad teeth. At the other end of the scale, you will sometimes hear that “your body needs sugar”, so perhaps we should not worry about it at all.
Sugar gets a pretty bad press. But as usual, the truth sits somewhere in the middle…
Sugar is not inherently “bad”, just as a piece of fruit is not automatically “good”. What matters is the type of sugar, where it comes from, how much we are consuming and what the rest of our diet and lifestyle look like.
So rather than demonising sugar, let’s understand it.
What actually is sugar?
Sugar is a type of carbohydrate. When we eat carbohydrates, many of them are eventually broken down into glucose, which enters the bloodstream and can be used by our cells for energy.
Glucose is particularly important for the brain, and it is also a useful fuel for working muscles, especially during higher intensity exercise. But an important distinction needs to be made.
Our bodies need glucose. That does not mean we need to eat added sugar
We can obtain glucose from all sorts of carbohydrate containing foods, including potatoes, rice, oats, pasta, bread, fruit, vegetables and pulses.
In fact, even if carbohydrate intake is very low, the body can manufacture glucose from other substrates through a process called gluconeogenesis.
So we have no physiological need to eat sweets, biscuits, or spoonfuls of sugar to keep ourselves functioning. That does not mean we cannot eat them, though.
Different sugars. What is the difference?
When we say “sugar”, we are actually talking about a family of different carbohydrates.
Some of the most common include:
Glucose is a simple sugar and one of the body’s main sources of readily available energy. It occurs naturally in foods like fruit and honey and is also produced when we digest many carbohydrates.
Fructose is sometimes called fruit sugar because it occurs naturally in fruit. It is also found in honey and is used in some processed foods and drinks.
Sucrose is ordinary table sugar. It is made from glucose and fructose and is commonly produced from sugar cane or sugar beet.
Lactose is the naturally occurring sugar found in milk and dairy products. It is made from glucose and galactose.
Maltose is made from two glucose molecules and is associated with starch digestion and malted foods.
Chemically, these sugars have differences. From a practical nutrition point of view, however, I am usually more interested in the food they come from than in whether someone has eaten glucose rather than fructose.
That's because the whole food matters.
An apple is not the same as a can of fizzy drink
An apple contains sugar. A sugary fizzy drink contains sugar… That does not make them nutritionally equivalent.
The apple comes packaged with fibre, water, vitamins, minerals and various beneficial plant compounds. Its physical structure and fibre content also influence how quickly we eat and digest it and how filling we find it.
A sugary drink can contain a substantial amount of free sugar with very little fibre, and we can consume it quickly without feeling particularly full.
Research comparing whole fruit and fruit juice supports the idea that the food source and physical structure matter. Whole fruit generally provides more fibre and tends to produce greater satiety than juice, while research increasingly suggests that the physiological effects of sugars depend partly on the food matrix in which they are consumed.¹ ²
This is why simply looking at the number next to “of which sugars” does not always tell the whole story.
The same applies to dairy. Natural yoghurt contains lactose, so the nutrition label will show sugar even if absolutely no sugar has been added. That is very different from a dessert-style yoghurt containing significant amounts of added sugar, syrups and flavourings.
Context matters.
Natural sugars, added sugars and free sugars
This is probably the most useful distinction to understand:
Naturally occurring sugars are those contained within foods such as whole fruit, vegetables and milk.
Added sugars are sugars added during manufacturing or preparation.
Then we have free sugars.
Free sugars include sugars added to foods and drinks, but also sugars naturally present in honey, syrups and fruit juices. That last one sometimes surprises people.
The sugar in a whole orange is contained within the physical structure of the fruit. Once we juice the oranges, much of that structure and fibre is lost or disrupted, making it considerably easier to consume the sugar from several oranges in a short period of time.
Again, this does not make orange juice “bad”. It simply means it should be treated differently from eating a whole orange.
How much sugar do we actually need?
Strictly speaking, we do not need to consume any free sugar. Our bodies need energy and glucose, but we can obtain these from other carbohydrates and foods.
In the UK, current guidance is that free sugars should provide no more than around 5% of daily dietary energy. For adults, this works out at roughly 30g of free sugars per day. That is approximately seven teaspoons of sugar.
Remember, this is a guideline, not a magical line in the sand. Eating 31g does not suddenly make your diet unhealthy, just as eating 29g does not automatically make it healthy. What matters much more is what happens consistently over weeks, months and years.
Why can too much sugar become a problem?
One of the main problems with foods containing lots of added sugar is that they can make it extremely easy to consume a lot of calories without feeling particularly full.
Think about how quickly you could drink 500 calories of a sugary drink compared with eating 500 calories of potatoes, vegetables and chicken - very different experience.
Foods containing lots of sugar can also be highly palatable, particularly when sugar is combined with fat. Biscuits, cakes, chocolate, pastries and desserts are obvious examples. There is nothing wrong with enjoying these foods, but they are very easy to overconsume.
Research looking at dietary sugar and body weight has found that when people reduce sugar intake without deliberately controlling total calories, body weight tends to fall, while increasing sugar intake tends to increase body weight. Interestingly, when sugar is exchanged for other carbohydrates without changing total calorie intake, the effect on body weight is much smaller.³
That is an important point.
It suggests that sugar is not uniquely fattening in some magical way. Rather, one problem is that a high-sugar diet can make it easier to consume more energy overall.
Regularly consuming more energy than we expend can lead to weight gain, and carrying excessive body fat, particularly around the abdomen, is associated with a range of health problems.
There is also reasonably consistent evidence linking higher consumption of sugar-sweetened drinks with an increased risk of type 2 diabetes. These studies are largely observational, so they cannot prove that sugary drinks are the sole cause, but the association is strong enough to justify being sensible about how often we consume them.⁴ ⁵
Sugar intake also affects dental health. A systematic review examining sugar intake and dental caries found consistent evidence that higher sugar consumption is associated with greater tooth decay, with lower caries rates when free sugar intake is kept lower.⁶
So rather than saying “sugar makes you fat”, I would put it slightly differently:
A diet containing lots of highly palatable, energy-dense foods can make it easier to consistently consume more calories than your body requires.
That is a much more useful way of looking at it.
How do I identify sugar in packaged foods?
This is where food labels can become confusing. In the UK, the nutrition information will usually contain a line saying: Carbohydrate, of which sugars
This tells you the total amount of sugars in the food, but it does not necessarily tell you how much has been added. For example, milk and plain yoghurt will contain sugar because they naturally contain lactose. That is why it is worth checking the ingredients list as well.
Sugar can appear under lots of different names, including:
Sugar
Sucrose
Glucose
Fructose
Dextrose
Maltose
Glucose syrup
Fructose syrup
Glucose fructose syrup
Invert sugar
Molasses
Honey
Agave syrup
Maple syrup
Fruit juice concentrate
One useful thing to remember: ingredients are generally listed in descending order by weight. So if sugar, glucose syrup or another source of free sugar appears near the beginning of the ingredients list, there is probably a reasonable amount of it in the product.
Do not be fooled by “healthy” sounding sugar
This is another area where marketing can outpace nutrition. Honey, maple syrup, agave nectar, coconut sugar and date syrup might sound more natural than ordinary white sugar. And some may contain tiny amounts of additional nutrients. But they are still predominantly sources of sugar.
Your body does not suddenly give maple syrup a nutritional VIP pass because it came from a tree. That doesn’t mean you shouldn’t use it. If you enjoy honey on your porridge, have some honey on your porridge. Just do not convince yourself that four tablespoons of it somehow doesn’t count because it is “natural”.
So which sugars should we avoid?
I wouldn't encourage anyone to think in terms of completely avoiding certain sugars. Instead, I would focus on reducing the foods and drinks that make it easy to consume large quantities of free sugar without providing much nutritional value or satiety.
Sugary drinks are probably one of the easiest places to start. Regular fizzy drinks, energy drinks, sweetened coffees and some fruit drinks can provide surprisingly large quantities of sugar without filling us up.
I would also pay attention to foods where sugar can quietly accumulate throughout the day. Sweetened breakfast cereals, flavoured yoghurts, cereal bars, sauces, biscuits, and snacks might seem insignificant on their own, but together they can add up.
That doesn't mean you should never eat them. It means being aware of them.
Can I eat sugar and still lose weight?
Absolutely. Weight loss requires consuming less energy than you expend over time. You do not have to remove sugar completely to achieve that.
In fact, the research on sugar and body weight supports the idea that energy balance is extremely important. When dietary sugar is exchanged for other carbohydrates while total calorie intake remains similar, changes in body weight are generally small.³
For many people, attempting to completely ban chocolate, biscuits, desserts or other favourite foods can also make a diet unnecessarily restrictive and difficult to maintain.
I would much rather someone had a sensible portion of chocolate a few times a week while eating well overall than spend Monday to Friday trying to be “perfect”, only to eat everything in sight at the weekend.
Nutrition does not need to operate at extremes.
You might also like: The Top Ten Barriers to Fat Loss (and How to Overcome Them)
What does a sensible approach look like?
For most people, I would focus most of the diet on minimally processed foods. Plenty of vegetables and fruit, adequate protein, whole grains and other fibre-rich carbohydrates, healthy sources of dietary fat, enough water and an appropriate overall calorie intake for your goals.
Then leave some room for foods that you simply enjoy. That might be a couple of biscuits with your coffee. It might be dessert when you are out for dinner. It might be a slice of birthday cake. Or it might be some chocolate while you are watching television.
You don’t need to earn it by exercising beforehand, and you don’t need to punish yourself afterwards. It is just food. If you need help with this, check out my nutrition support services.
The takeaway
Sugar is not poison.
It is not something we need to fear, and eating a piece of cake does not suddenly undo all the positive things you have done with your diet. At the same time, pretending that the amount of sugar we consume does not matter is not particularly helpful either.
Our bodies require glucose, but we do not have a nutritional requirement for added or free sugars. The sensible approach is to get most of our nutrition from foods that provide protein, fibre, vitamins, minerals and other useful nutrients, while keeping free sugars to a reasonable level.
Learn to read labels. Pay particular attention to liquid calories and hidden sources of added sugar. Choose whole fruit more often than juice. Then allow yourself to enjoy some of the foods you love without feeling guilty. Because a healthy diet is not defined by one food. It is defined by what you do most of the time.
And if you can eat well, exercise regularly, maintain a healthy body composition and still enjoy a bit of chocolate or dessert along the way, that sounds like a much more realistic definition of a healthy lifestyle to me.
Alan Griffin
Griffin Fit Personal Training
References
Benton D, Young HA. Whole Fruits Versus 100% Fruit Juice: Revisiting the Evidence and Its Implications for US Healthy Dietary Recommendations. Nutrients. 2025. Review of evidence comparing whole fruit and fruit juice, including fibre, satiety and health outcomes.
Are all sugars equal? Role of the food source in physiological responses to sugars with an emphasis on fruit and fruit juice. Proceedings of the Nutrition Society. 2024. Review discussing how food structure, fibre, energy density and other components influence the physiological response to sugars.
Te Morenga L, Mallard S, Mann J. Dietary sugars and body weight: systematic review and meta analyses of randomised controlled trials and cohort studies. BMJ. 2013;346. doi:10.1136/bmj.e7492.
Greenwood DC, Threapleton DE, Evans CEL, et al. Association between sugar sweetened and artificially sweetened soft drinks and type 2 diabetes: systematic review and dose response meta analysis of prospective studies. British Journal of Nutrition. 2014;112(5):725 to 734. doi:10.1017/S0007114514001329.
Li B, Yan N, Jiang H, Cui M. Sugar and artificially sweetened beverages consumption linked to type 2 diabetes, cardiovascular diseases and all cause mortality: a systematic review and dose response meta analysis of prospective cohort studies. Nutrients. 2021;13(8):2636. doi:10.3390/nu13082636.
Moynihan PJ, Kelly SAM. Effect on caries of restricting sugars intake: systematic review to inform WHO guidelines. Journal of Dental Research. 2014;93(1):8 to 18. doi:10.1177/0022034513508954.
UK guidance
The Scientific Advisory Committee on Nutrition recommends that average free sugar intake should not exceed 5% of dietary energy. For adults, NHS guidance translates this to approximately 30g of free sugars per day.