I don’t know about you, but I’m a lot more disciplined with my diet and exercise in the colder months than the warmer ones.
Longer days and better weather might mean I’m more active on the bike in the summer, but winter instils more structure.
Lengthier evenings offer more time for structured workouts on my Wattbike, but crucially, I travel less – for work and leisure.
In my world, travel means flux and the first casualty of being on the road, whether on a work assignment or away with family, is always my diet. I’m sure I’m not alone in this. Multi-course meals in restaurants, monster hotel breakfasts… on summer holidays, a daily gelato is a family ritual.
It’s got me thinking a lot about sugar and my relationship with it: whether I have too much in my diet; if so, how I could reduce it; the relationship between sugar and exercise, and whether sugar addiction – an idea that gets bandied about – is a real concern.
I certainly crave sugar, that’s not up for debate. In a similar way to alcohol – which is definitely addictive – when I get into a run of days consuming a lot of sugar, such as on holiday or when I’m away from home, my intake can snowball.
In my more disciplined winter periods, my habits improve and it’s not something I think about constantly. But is that enough to make sugar addictive? What is the definition, exactly, of an addictive substance? More on that later.
Off the leash
For now, we’ll look at the amount of sugar that should be in our diets.
In the UK, when the National Health Service talks about the sugar we should be cutting back on, it’s talking about ‘free sugars’ and natural sugars.
Free sugars are those that are added to foods and drinks such as fizzy drinks and breakfast cereals, which may have been refined and processed.
It’s not necessarily only refined sugars that we should be limiting, but natural ones, found in smoothies and honey, too.
‘Free’, in this definition, means sugar that’s no longer in the cells of the food, such as an orange. The fibre within the orange, which contributes to maintaining a healthy gut, is removed and stops us from feeling full.
If you end up drinking half a carton of fresh orange juice, you might be consuming the juice of 10 oranges, but a lot of the good stuff is left on the table.
While sugar found naturally in milk, fruit and vegetables is of less concern, it’s still included in the daily recommended limit of sugar found on food labels.
Worked your way through a punnet of strawberries at lunch? That natural sugar is still going to tot up and end up in belly fat if you’re consuming too many calories.
The NHS says adults shouldn’t be eating more than 30g of free sugar a day – that’s seven sugar cubes, which isn’t much when you think a can of full-fat cola can contain nine.
In the USA, 50g is the recommended limit in a daily 2,000-calorie diet.
In reality, these aren’t limits we should be rubbing up against – this type of sugar has no nutritional value, we can live without any of it and excessive consumption can lead to the development of type 2 diabetes. So, maybe that’s the only reason you’d ever need to cut it out entirely.
I’ve certainly met people, cyclists like me, who’ve tried this. It’s no mean feat, though. Western food culture, with free sugar finding its way into all manner of packaged foods, makes it hard to escape.
But that’s forgetting there are many things in this life that we want but don’t need, such as the substances at the heart of defined addictions – alcohol and drugs, for example.
Can sugar, then, go beyond being something we crave, something that makes us feel good momentarily and lights up the dopamine centres in our brains, to become a full-blown addiction?
“The term addiction can be quite triggering and evoke a lot of emotion in people,” says Dr Sam Impey, former lead nutritionist at British Cycling and current scientific advisor for Puresport, the supplement and hydration firm.
“It’s probably the substance that the human body is most evolutionary designed to hunt and gather because it’s the most efficient source of energy for our bodies.
“You have sugar sensors in the lining of your mouth, which tell your brain to expect carbohydrates when you eat them. Our bodies are incredibly sensitive to the amounts of carbohydrate in our diet.
“I don’t think that sugar per se is addictive, but we have a good internal reward system from having an appropriate amount of carbohydrates and sugars in our diet.”
Many scientists agree with Dr Impey, but that hasn’t stopped the debate over sugar.
A 2007 French study, famously, found that rats preferred sugar-sweetened water to cocaine.
In 2016, however, a paper published in the European Journal of Nutrition, which reviewed the research on the idea of sugar addiction, argued there was little evidence to support it in humans.
It found addiction-like behaviours in animals, such as bingeing, only occur in the context of intermittent access to the sweet things, rather than on the neuro-chemical level.
If we put the possibility of addiction to one side and treat our hunger for sugar as cravings, how might we control our urges and reduce our sugar intake?
A 2025 study from Columbia University in New York put our ‘sweet tooth’ under the spotlight by mapping, for the first time, the 3D structure of the human tongue’s sweet taste receptor.
This, the researchers say, could lead to the discovery of new regulators of the receptor that would alter our appetite for sugar.
Humans’ sweet receptors, unlike those for bitter and sour, haven’t evolved to be particularly sophisticated, says the study.
This helps us focus on finding and detecting sugar-rich foods for energy, but evolution hadn’t reckoned on the bountiful supply of sugar in the Western diet in 2025.
“The leading role that sugar plays in obesity cannot be overlooked,” says the study’s co-author Juen Zhang.
“The artificial sweeteners that we use today to replace sugar just don’t meaningfully change our desire for sugar. Now that we know what the receptor looks like, we might be able to design something better.”
Fuel in the tank
If evolution has shaped us to seek out sweet things, and some of us have hard-to-control cravings for sugar-filled foods, it puts someone like me – who frequently cycles long distances at high intensities and relies on far more than 30g of free sugar a day to power workouts – in something of a bind.
My own weight tends to yo-yo somewhat, depending on how much I’m cycling.
The problem is I don’t tend to adjust my off-bike diet when I’m doing less cycling: like many cyclists, I enjoy a cake stop on a ride, but I also just enjoy a cake stop.
Does the bag of gummies I devour on a bike ride give me the cravings to do the same in front of the TV?
Cyclists at the Tour de France, for example, consume up to 6,000 calories a day during the toughest stages, and more than 100g of sugar an hour when on the bike. The higher the number, the better, in fact – it all powers forward motion.
In these situations, free sugars – simple sugar energy gels and gummies, for instance – are not just fine, but encouraged. They’re broken down and used fast by the body and don’t lead to a spike in blood sugar, which is not the case when you’re at rest.
When at rest, the muscles – once at capacity – don’t need the sugar and, with no place for the excess to go, blood sugar spikes.
In the general population, over time, this causes problems: type 2 diabetes can develop, where the body can’t create enough insulin – the hormone that regulates blood glucose and is deadly without controls.
The solution for me seems to be in reshaping off-bike habits associated with sugar, perhaps by being more aware of how the food industry stacks the odds against me in terms of my sugar cravings.
Dr. Impey continues: “The challenge comes in the development of modern food sources – things have become hyper-palatable with the addition of sweeteners and emulsifiers that change the mouth feel.
“You have to look at what sugar is packaged in, especially in modern, processed food sources. The issues come not necessarily directly from sugar, but from some of the other stuff around it.”
In terms of exercise, Dr. Impey says, we shouldn’t be afraid of fuelling it with sugar.
“This is something that’s really changed in the last few years – this move to fuelling effectively during training.
“Not just to improve training quality and outcomes – you’ll definitely get better adaptations and performance – but also the additional benefits around being in a slightly better total energy balance.”
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