9 foods that could be worsening your mental health

Healthy eating concept with vegetable and human head drawing on gray wooden background

“What we eat directly influences brain chemistry, inflammation levels and gut health,” explains registered nutritionist Zara Hiridjee. “All of these impact mood and mental wellbeing. A balanced diet can instead provide a steady release of energy, a strong gut-brain connection and key nutrients for mood regulation.”

And when it comes to food and mental health, it’s rarely a case of “good vs. bad” food, Hiridjee stresses, but instead about balance and moderation and how certain foods affect us over time. “The issue isn’t necessarily eating these foods occasionally but rather relying on them in excess or as a staple in our diet.

However, there are certain foods and food groups that may exacerbate poor mental wellbeing if it’s a regular part of your daily diet.

Foods that may worsen your mental health

Ultra-processed foods

Highly processed foods like some packaged snacks, sugary cereals and ready meals are often loaded with preservatives, artificial additives, and inflammatory oils. These ingredients can negatively impact gut health, which is directly linked to brain function via the gut-brain axis.

“These foods often stripped fibre and essential nutrients, meaning they don't provide sustained energy or nourishment for brain health,” adds Hiridjee. “That said, if someone enjoys the occasional dessert or convenience meal now and then, it's unlikely to have a major impact. The key is ensuring that the overall diet provides a solid foundation of whole foods, so occasional indulgences don't disrupt energy levels or mood stability.”

Sweet Cocoa Chocolate Sugar Cereal Puffs with Milk

Refined sugars

Sugary foods such as sweets, pastries, fizzy drinks and white bread can cause rapid spikes in blood sugar levels, followed by crashes that may contribute to mood swings, fatigue and irritability.

“In small amounts, sugar isn't inherently harmful, and for some, an occasional sweet treat can be part of an enjoyable and balanced diet,” says Hiridjee. “The problem arises when refined sugars become a regular feature.”

Studies suggest a strong link between high sugar intake and increased risks of depression and anxiety.

Granulated sugar in a wooden scoop or bowl on an old oak table.

Artificial sweeteners

Aspartame, saccharin and sucralose which are commonly found in diet fizzy drinks and sugar-free products, have been linked to neurochemical imbalances that may negatively impact mood on cognitive function. Some research suggests that artificial sweeteners can interfere with neurotransmitters like serotonin, which plays a key role in mood regulation.

Fried fast foods

Regular consumption of fried foods such as chips, fried chicken and processed snacks, has been associated with an increased risk of depression. These foods are often high in trans fats, which can cause inflammation in the brain and impair neurotransmitter function.

A bowl of chunky chips next to a pot of gravy at Buyers Club, Liverpool

Excessive caffeine

While moderate caffeine consumption can actually have cognitive benefits, excessive intake can contribute to anxiety, restlessness and sleep disturbances.

“Caffeine can be both a performance booster and an anxiety trigger depending on the person and the amount consumed,” Hiridjee explains further. “Excessive caffeine, especially later in the day, can overstimulate the nervous system, disrupt your sleep, and heighten feelings of anxiety.”

“Some people metabolise caffeine slowly, making them more sensitive to its effect, while others tolerate it well. If sleep issues, jitters or mood fluctuations are a concern, cutting back or switching to lower caffeine options like green tea may help.”

Alcohol

Unsurprisingly alcohol can have a very negative impact on your mental health, as it's actually a depressant that affects neurotransmitter levels. While occasional drinking may not be harmful, regular or excessive alcohol consumption can interfere with brain function and emotional stability. It doesn't help that for some, an alcoholic drink may feel like a stress reliever in the moment however its long term effects on brain chemistry and overall mental wellbeing can actually be quite significant.

“One of the biggest issues is how alcohol affects neurotransmitters like serotonin and dopamine. Initially it can trigger a short-lived boost in mood, but over time, regular alcohol use disrupts the balance of these chemicals, leading to increased anxiety, low mood and even depression,” Hiridjee says.

“Essentially it depletes the very neurotransmitters that help regulate emotions, leaving you more vulnerable to mood swings and emotional lows once the effect wears off.”

And that’s without mentioning the impact alcohol has on your sleep, its effect on your gut health and its impact on lowering your inhibitions and impairing judgement, which can lead to regrettable decisions or reckless behaviour, all of which can increase stress, guilt and anxiety in the long run.

Processed meats and high sodium foods

Some deli meats, hot dogs and tinned soups often contain high levels of salt and preservatives, which can contribute to bloating, dehydration and disruptive neurotransmitter activity. Some studies have shown that excessive sodium intake may be linked to increased stress levels and cognitive decline.

Dairy

While dairy is a great source of essential nutrients, in some rare instances an individual may be sensitive to casein, a protein found in milk, which can contribute to inflammation and may worsen symptoms of anxiety and depression.

Highly processed vegetable oils

Oils high in omega-6 fatty acids, such as corn and sunflower oil can contribute to chronic inflammation in the body and brain when consumed in excess. An imbalance between omega-6 and omega-3 fatty acids has been linked to increased risks of depression and cognitive decline.

Close up of young woman grocery shopping in a supermarket. Standing by the aisle, holding a bottle of organic cooking oil, reading the nutritional label and checking ingredients at the back

Foods that can better your mental health

Again, the importance of balance is important here. Getting the right amount of nutrients that can have positive impacts on your mental wellbeing is key. This can include:

Oily fish rich in omega-3 fatty acids that are crucial for brain health and supporting neurotransmitter function.
High quality protein that provide amino acids that can help produce neurotransmitters like serotonin and dopamine.
Wholegrains that provide slow-releasing energy and support serotonin production.
Yogurt, kimchi and other fermented foods that can help maintain a healthy gut microbiome.
Leafy greens and other foods rich in B vitamins that are essential for energy production and brain function.
Magnesium rich foods like dark leafy greens, nuts and seeds that helps regulate stress and brain function.
Shellfish, beef and chickpeas that are abundant in zinc, which is again important for stress regulation.
Olive oil, avocados and full-fat dairy that contain healthy fats, which support cognitive function.
Water, herbal teas and other hydrating drinks that can help reduce dehydration and brain fog.

So yes, what you eat matters more than you probably thought when it comes to good mental health. Ensuring processed sugars, artificial additives, unhealthy fats and ultra-processed foods don’t become a core part of your diet will only help your overall health in the long-term. It isn’t about achieving pure nutritional perfection, but making diet choices that help you feel nourished, satiated and most importantly, happy. So perhaps instead of reaching for a quick-fix to your sugar or fast-food cravings, try filling your plates with whole, nutrient-dense food that nourishes both mind and body. Small changes and regular commitment can have a big impact after all.