It has been 20 years since chef Jamie Oliver launched his infamous war on “turkey twizzlers” and other unhealthy school lunches — and yet many teenagers are still fuelled by junk foods. Varenya Pangaluri, 14, from Queen Elizabeth’s School Barnet, says students deserve better.
You know that feeling when you’re sitting in class, trying to focus, but your brain feels like it’s moving in slow motion? That sluggish, foggy feeling isn’t just because school is dull — it’s often because of what we eat. Junk foodA term used to describe food that is high in sugar or fat without much nutritional value. has become a normal part of student life, but most people don’t realise just how much it’s affecting our ability to think, learn, and even feel good. If we want to do better in school and feel more energised, we need to take a serious look at what’s on our plates.
Our brains need the right fuel to function properly, just like a car needs good petrol to run smoothly. But according to Public Health England, many teenagers in the UK are still getting more than half of their daily calories from ultra-processed foods — things like crisps, sweets, and takeaway meals. These foods don’t provide the nutrients our brains need to focus and retain information.
A UK study published by The British Nutrition Foundation found that diets high in sugar and low in fibre are linked to poor concentration and lower academic performance. You might feel a quick buzz after eating sugary snacks, but the crash that follows makes it much harder to stay alert.
It turns out that what you eat can actually affect your marks. A study in The Journal of School Health (American) showed that students who regularly eat a healthy breakfast score 17% higher on tests compared to those who skip it or grab something sugary on the way.
Here in the UK, the University of Leeds found that primary school children who regularly eat breakfast perform significantly better in tests than those who don’t. And the University of Cambridge found that secondary school students who consume high levels of junk food perform 10% worse in subjects like maths and science.
Food doesn’t just affect grades — it plays a huge role in mental health too. According to the British Dietetic Association, a poor diet lacking in essential nutrients can lead to higher levels of anxietyA feeling of unease or worry. It can be mild or very severe., low mood and fatigue in teens. Our brains need nutrients like omega-3 fats (found in fish and nuts), iron, and B vitamins to support emotional wellbeing.
A report from the American Psychological Association found similar results — teens with diets high in fast food and sugary snacks were up to 40% more likely to experience depression.
If food is this important, why aren’t schools doing more?
Some schools still sell fizzy drinks and sweets in vending machines, and school dinners often contain too many processed ingredients. But change is possible — and it works.
In California, some schools replaced processed lunches with fresh, whole foods. The results? Test scores increased by 12%, and classroom behaviour improved significantly.
But we don’t have to look across the Atlantic for solutions. In the UK, there are growing efforts to tackle this issue. A London secondary school piloted a “healthy tuck shop” scheme, offering fruit, nuts, and wholegrain snacks instead of sweets. As a result, students reported feeling more alert in afternoon lessons, and behaviour incidents dropped by 20%.
The Food for Life programme, led by the Soil Association, supports schools across the UK to serve nutritious meals using local produce, and even helps students grow their own food. In Wales, the Healthy Schools Scheme encourages schools to promote balanced diets and has shown positive results in both behaviour and academic engagement.
The evidence is clear: what we eat directly affects how we think, feel, and learn. If we want students to thrive — not just academically, but mentally and emotionally — we need to give them the right fuel. That means making better food choices ourselves and calling on our schools to step up.
Healthy food shouldn’t be a luxury or a punishment — it should be the norm. Because no one deserves to sit through maths with a brain full of fog and a stomach full of fizzy drinks.
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Keywords
Junk food – A term used to describe food that is high in sugar or fat without much nutritional value.
Anxiety – A feeling of unease or worry. It can be mild or very severe.
Sources:
Public Health England, “National Diet and Nutrition Survey,” 2023.
● British Nutrition Foundation, “Nutrition and Brain Function in Children,” 2022.
● University of Leeds, “Breakfast Eating and Academic Performance,” 2022.
● University of Cambridge, “Processed Foods and Academic Performance,” 2022.
● British Dietetic Association, “Food and Mood,” 2023.
● American Psychological Association, “Teen Diets and Mental Health Risk
Factors,” 2023.
● Journal of School Health (American), “Breakfast and Student Performance,”
2023.
● Food for Life (UK), “Improving School Food,” 2024.
● Healthy Schools Scheme (Wales), “School Health Promotion in Action,” 2023.
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