Blood Sugar And Mood

Do you suffer with diabetes and mood swings? Balance your blood sugars to support mental well-being.

Blood Sugar And Mood  photo

Did you know your blood sugar levels can affect your mood?

This article will explore the ways in which high and low blood sugar levels can affect mood and mental well-being. By being more aware of how the foods you eat affect how you feel, you will be able to make more informed decisions to support your general well-being.

How do blood sugar levels affect mood?

Sugary foods and refined carbohydrates such as cakes, sweets, biscuits, crisps, white bread and white pasta cause blood sugar levels to rise rapidly in the short term. This triggers the release of the hormone insulin which has the role of shunting sugar from the blood into liver and muscle cells so that blood sugar levels do not get dangerously high. If large amounts of sugar and refined carbohydrates are consumed, this causes a steeper drop in blood sugar levels.

Frequent spikes and drops in blood sugar levels can trigger the release of stress hormones such as cortisol and adrenaline, which can contribute to anxiety, irritability, hunger and mood swings.

Consuming sugary food also has the effect of increasing feel-good hormones such as dopamine and serotonin in the short term, however in the long-term this has been associated with increased symptoms of anxiety, depression, negative emotions and reduced cognitive function.

These effects may partly be due to the effect of excess sugar on the immune system and gut microbiome. Diets high in carbohydrates are associated with inflammation, which is thought to play a role in conditions such as depression and anxiety. As biochemical communication pathways exist between the gut and brain (aka. the gut-brain axis), excess dietary sugar can also impact the gut microbiome in ways which affect brain health and mood. See our other article on the gut-brain connect 'The Link Between Gut Health And Mental Health '.

So what can you do to balance blood sugar levels?
  • Limit foods high in sugar and refined carbohydrates (biscuits, cakes, sweets, crisps, chips, white bread and white pasta).
  • When preparing a meal, aim to fill your plate with non-starchy vegetables such as rocket and other leafy greens, tomatoes, spinach, broccoli, peppers or mushrooms. Choose complex carbohydrates such as brown rice, whole-wheat pasta, butternut squash or sweet potatoes, keeping them to no more than a quarter of your plate. Ensure your meal contains a portion of good quality protein such as meat, fish, eggs, tofu, quinoa or cooked beans.
  • Eat a rainbow diet which includes a range of different coloured fruits and vegetables such as red cabbage, sweet potato, bell peppers, berries, apples, oranges, dark leafy greens, onions, garlic, herbs and spices.
  • If you are craving something sweet, eat a piece of fruit like an apple, orange or some berries with yoghurt or cheese. Nuts and dark chocolate also make a good low-sugar snack. See our recipe for dark chocolate bark:
  • Take a walk after meals as this also helps to maintain healthy blood sugar levels.

Firth, J., Gangwisch, J., Borsini, A., et al., 2020. Food and mood: how do diet and nutrition affect mental wellbeing? The BMJ [online], 369. Available at:

Jacques, A., Chaaya, N., Beecher, K., et al., 2019. The impact of sugar consumption on stress driven, emotional and addictive behaviours. Neuroscience & Behavioural Reviews, 103, pp. 178-199.