Welcome back to Just Curious, Strong Women’s weekly series exploring all the random health and fitness questions you’ve always wondered about but never got the answers to.

This week, we’re exploring whether diet could be the key to keeping your cortisol levels under control (and why that matters).

Scroll through any health space on social media, and it won’t take you long until you find a video or infographic talking about cortisol. From the potential benefits of low-cortisol workouts to how to get rid of ‘cortisol face’, the internet has plenty to say.

Also known as the stress hormone, cortisol isn’t inherently bad for you; in fact, it’s responsible for waking you up and activating your immune response. Too much cortisol, however, can be a problem. We’re not talking about the spike you might get while public speaking or taking part in a HIIT class, but the sustained high levels that come from chronic stress.  

While these sustained high levels probably won’t make your face puffy, they can disrupt your sleep, lead to digestive problems and increase your risk of cardiovascular health issues, which is why being mindful of your stress – and subsequent cortisol levels – is important.

We know that interventions like regular exercise (balanced out with rest) and good sleep hygiene can make a difference, but can the foods we eat also help to keep our cortisol levels in check? To find out, we spoke to Nichola Ludlam-Raine, a specialist registered dietitian and author of How Not To Eat Ultra-Processed. Below, she explains everything you need to know. 

The foods we eat can both positively and negatively affect our cortisol levels, so it’s important to be aware of what foods and drinks you’re putting into your body on a daily basis.

“Cortisol is regulated by the hypothalamic-pituitary-adrenal (HPA) axis, and its levels can be influenced by nutrition and eating habits,” Ludlam-Raine explains.

Failing to provide your body with the correct nutrients, or conversely, giving your body plenty of nutrients that help to support your wellbeing, can also determine how much stress it is under, leading to a change in your cortisol levels. It’s all about finding a balance. 

According to Ludlam-Raine, there are three main ways a healthy diet can lower cortisol levels:

1. Reducing inflammation

“Chronic inflammation can lead to increased cortisol levels,” she explains. “An anti-inflammatory diet rich in omega-3 fatty acids (found in fatty fish and walnuts), fruits, vegetables and whole grains can help to reduce inflammation.”

2. Stabilising blood sugar levels

“Consuming a balanced diet with complex (low GI) carbohydrates, lean protein and healthy fats can help to stabilise blood sugar,” Ludlam-Raine says. “Blood sugar fluctuations, such as those caused by consuming refined carbs or skipping meals, may trigger cortisol release.”

3. Preventing dehydration

“Dehydration is a physical stressor and has been linked to increased cortisol levels,” she says. “Drinking enough water supports overall stress management.” 

A poor, unbalanced or restrictive diet can have the opposite effect to a healthy one, increasing cortisol levels as a result, says Ludlam-Raine. Here’s how:

1. Blood sugar spikes

“Diets high in added sugars and refined carbohydrates can cause rapid spikes in blood sugar, leading to an overproduction of cortisol,” Ludlam-Raine explains.

2. Excessive caffeine intake

“While moderate caffeine intake may boost alertness, excessive consumption can increase cortisol secretion, particularly during stressful situations,” Ludlam-Raine says.

3. Low-calorie consumption

“Severely restricting calories can act as a physical stressor, triggering increased cortisol production,” Ludlam-Raine says. “This is often seen in extreme dieting or fasting for prolonged periods.” 

While there are a few key nutrients that can help to keep your cortisol levels in a healthy place, Ludlam-Raine stresses that overall dietary pattern is the most important factor here.

“Focusing on an overall-balanced diet with whole, minimally processed foods is more impactful than isolating specific ‘cortisol-reducing’ foods,” she says.

However, if you do want to add a few hero foods to your balanced diet to give your cortisol levels a helping hand, Ludlam-Raine says the following may be beneficial.

1. Dark chocolate

“Rich in polyphenols, dark chocolate has been shown to reduce stress and cortisol levels,” Ludlam-Raine says. “Enjoy a couple of squares of dark chocolate a day (70% cocoa or more).”

2. Fatty fish

“Omega-3 fatty acids found in salmon, mackerel and sardines may reduce cortisol and inflammation,” she explains. “We should aim for two portions of fish a week, one of which is oily.”

3. Bananas and avocados

“High in potassium, these foods may help to regulate blood pressure and cortisol,” Ludlam-Raine suggests. “Enjoy bananas on porridge and avocado on wholemeal toast.”

4. Fermented foods

“Probiotic-rich foods like live yoghurt, kefir and kimchi may support gut health and positively influence stress hormones,” she says. “Include these daily. You could have yoghurt in overnight oats or as a snack, for example.”