Why Does Processed Sugar Increase My Anxiety?

It’s no secret that what we eat can have a big impact on how we feel – not just physically, but mentally too. One of the things some people report when trying to improve their mental wellbeing is a link between sugar and anxiety. But is there really a connection? Can that chocolate bar or slice of birthday cake be doing more than just satisfying a craving?

For me, processed sugar has definitely played a role in my anxiety levels over the years. It’s something I became more aware of during my weight loss journey, and efforts to improve my overall wellbeing.

When I gained weight in the past, a big driver behind it was anxiety. Like a lot of people, I turned to food for comfort, and that often meant sugary snacks or processed treats. At the time, I didn’t really make the connection between what I was eating and how I was feeling. But once I started exercising more regularly – especially a mix of cycling with varied intensities, Olympic lifting and general strength training – I noticed a significant drop in my anxiety levels.

Exercise has become one of the biggest tools in my kit for managing anxiety. I do a mix of cycling, some rides easy, some more intense, and I lift weights too. Olympic lifting and structured cycle training in particular seem to do wonders for both my mood and my focus. The rhythm of it, the challenge, the way it makes me feel afterwards – it all helps.

But exercise alone isn’t the full picture. Sugar plays a role too, and I’m not just talking about the obvious stuff like cakes and sweets. I mean the kind of processed sugar you find in things like chocolate bars, fizzy drinks, shop-bought sauces and even some so-called “healthy” snacks.

Last week was my birthday. Naturally, I had more treats than usual – I’m a firm believer in enjoying special occasions. But by the time the celebrations wrapped up, I started to feel that familiar sense of anxiety creeping in. Restless sleep, jittery thoughts, feeling like I couldn’t quite settle. It wasn’t anything major, but it was noticeable. I hadn’t changed much else, I’d still been exercising and I wasn’t overly stressed. The big difference was food. More sugar, more snacks, more grazing.

After two or three days of getting back to my usual routine – healthier meals, more structure, very little processed sugar – and a good few sessions of training, my anxiety eased off again. That tight-chested, on-edge feeling just disappeared. It’s not the first time that’s happened either. So it’s got me thinking – can processed sugar really increase anxiety?

Why Processed Sugar Might Affect Anxiety

The relationship between sugar and anxiety isn’t totally straightforward, but there are several ways it could be playing a part.

Blood sugar spikes and crashes

Processed sugar is quickly absorbed into the bloodstream, causing a rapid rise in blood sugar levels. This can give you a temporary lift, but it’s often followed by a sharp drop as your body releases insulin to bring things back down. That crash can leave you feeling shaky, tired, irritable or even panicky – all feelings that can mimic or trigger anxiety, especially if you’re already prone to it.

Gut health and the brain connection

The health of our gut has a direct impact on our mood and mental wellbeing. Processed sugar can negatively affect gut bacteria, throwing off the balance that supports healthy brain function. Some research suggests that poor gut health might increase the risk of anxiety and depression. If sugar is irritating your gut, it could easily be affecting your mood as well.

Inflammation and brain function

Chronic inflammation in the body has been linked to mental health issues. Eating a lot of processed sugar is known to promote inflammation, and while it’s not the only factor, it’s thought that ongoing inflammation might interfere with brain chemicals that regulate mood and anxiety.

Impact on sleep

Sugar can also mess with your sleep, especially if you’re having it later in the day. Poor sleep is a huge factor in anxiety levels. If sugar is causing restless nights, waking you up in the middle of the night, or making it harder to fall asleep, you’re much more likely to feel anxious the next day.

The cycle of cravings, crashes and guilt

It’s not just the physical effects, there’s also the mental loop. Sugar is a quick fix when you’re feeling low, but it often leads to guilt or regret, especially if you’re trying to eat healthier. That can cause its own anxiety. Plus, the highs and lows from constant sugar spikes can create a craving cycle that feels hard to break, adding another layer of stress to the mix.

Why Some People Don’t Notice a Difference

Not everyone reacts the same way to sugar. Some people seem to be able to have it without any noticeable shift in their mood. Genetics, gut health, hormone levels, stress tolerance and overall diet might all play a role.

The type and amount of sugar matters too. Having a piece of fruit with natural sugars and fibre is very different from having a couple of doughnuts and a sugary drink. It’s usually the highly processed, refined sugars eaten in larger quantities that cause the biggest problems.

So What Can You Do?

If you think processed sugar might be playing a part in your anxiety, there are some simple steps you can take without having to overhaul your entire diet.

Track your patterns
Keep an informal log for a week or two. Note what you eat and how you feel afterwards. You might notice certain sugary foods trigger more noticeable crashes or anxiety symptoms.
Prioritise balanced meals
Aim for meals that include a good mix of protein, healthy fats and fibre. This helps keep blood sugar more stable and reduces cravings for quick sugar fixes.
Swap sugary snacks for steadier options
Instead of reaching for a biscuit or chocolate bar, try snacks like Greek yoghurt with berries, peanut butter on apple slices, or a handful of nuts with some fruit.
Move your body
Regular exercise – even just a brisk walk or 15 minutes of home workouts – can make a big difference to mood regulation and blood sugar control. I’ve found that a mix of cardio and strength work, like within my sports coaching for strength and endurance, is ideal.
Be mindful of sugar timing
If you’re going to have something sweet, earlier in the day is usually better so it doesn’t interfere with sleep.
Stay hydrated
Dehydration can make you feel more sluggish and anxious too, so make sure you’re drinking enough water throughout the day.
Be kind to yourself
A slice of birthday cake or a chocolate after dinner isn’t the end of the world. It’s not about cutting sugar out completely but finding a balance that supports your mental wellbeing. And if you’re looking for support to lose weight in a sustainable way, working with someone who understands the mental side of things can make a big difference too.

For me, paying attention to processed sugar intake, combined with regular cycling, lifting and generally moving my body, has been one of the best ways to keep my anxiety manageable. It’s not about being perfect, but it is about understanding what triggers might exist, and knowing I can do something about it.