“Sweet food has been found to induce positive feelings in the short-term. People experiencing low mood may eat sugar in the hope of alleviating negative feelings. (…) a high intake of sugary foods is more likely to have the opposite effect on mental health in the long-term.”

~ Anika Knüppel, UCL Institute of Epidemiology and Public Health


More and more of us are becoming aware of how our dietary choice impacts our physical and mental well-being. We now know that sugar can lead to arthritis, insomnia, fatigue, decreased immune system, chronic inflammation, brain fog, cancer, and obesity.[1]

To curb the rapid growth of diet-related diseases, health experts have recommended widespread interventions in sugar consumption.

In the UK, adults consume approximately double the recommended level of sugar.[2] Sugar is particularly linked to depression, with major depression predicted to be the primary cause of disability by 2030.[3] However, until recently, the connection between a high sugar intake and poor mental health was unknown among the general public.

In this article, I will explore the three main areas where sugar impacts mental health; behaviour, mood, and memory.

1.   Behavioural

Sugar induces cravings and rewards that are comparable in magnitude to addictive substances such as cocaine.[4] It activates the regions of the brain associated with the reward response. When we consume sugar, our neural pathways are activated, and dopamine is released. Dopamine is our feel-good hormone that reinforces pleasurable behaviours that are key to our survival, such as eating and sex.

However, in the case of sugar, the neurochemical adaptations are acute and mimic the effects of opiates.[5] This leads to intense sugar cravings, a tendency to binge on sweet foods, the onset of withdrawal symptoms, and sensitisation. These are key indicators of misuse, and more significant quantities of the substance, in this case, sugar, will be required to reach the same level of reward.

2.   Mood

Numerous studies have demonstrated that sugar negatively impacts mood.  Research has connected sugar with an increased risk of anxiety, depression, and schizophrenia. In the short term, a rollercoaster of sugar consumption produces an intense high followed by a crash of blood sugars that can cause irritability, sadness, and anxiety.

However, sugar causes inflammation within the human body in the long term, leading to chronic inflammatory disorders affecting the brain, the immune system, heart, and major organs. Additionally, recent studies have demonstrated that depression is associated with a chronic inflammatory response[6] that could be induced by or exacerbated by high sugar consumption. A 2017 study found that those with a high sugar intake were 23% more likely to be diagnosed with a mental disorder and depression than those who consumed little sugar.[7]

Studies have additionally established a connection between sugar and anxiety.

A high sugar intake and the subsequent crash can also cause lethargy, decreased cognitive function, difficulty focusing, trembling, and blurred vision, which can be interpreted as signs of anxiety. This can cause a person prone to panic attacks or anxiety to have heightened awareness, worry, and fear of their physical symptoms, further perpetuating them.

3.   Brain Function

The low-grade chronic inflammation from a diet high in sugar causes numerous changes in brain function, including reduced mental capacity, slow motor speed, and deficits in focus and memory.

Research has demonstrated that a diet high in added sugar decreases BDNF, a brain chemical responsible for learning and new memory formation. BDNF levels are also associated with dementia. In addition, it has also been evidenced that persistent exposure to high blood sugar levels can contribute to brain shrinkage and damage, particularly amongst people with diabetes.

The Good News

Our bodies are not meant to metabolise the high quantities of sugar present in our diet, but inflammatory damage from sugar is not permanent if positive action is taken. Memory damage can be resolved by following a low sugar diet, and mental health conditions caused or exacerbated by sugar intake can be eased.

Education and understanding around the role sugar plays in our physical and mental health is growing, and we are understanding, more than ever before, how intricately our mind and body are connected. By reducing or eradicating our sugar consumption, we can nurture ourselves physically and psychologically and move towards optimum health free from addictive substances and their detrimental side effects.

If you are experiencing mental health issues related to a high sugar intake or are having difficulty reducing your sugar consumption, please contact me, Dr Bunmi Aboaba, Food Addiction Coach, by following this link.


[1] Public Health England. National Diet and Nutrition Survey: Results from Years 1–4 (combined) of the Rolling Programme (2008/2009 -2011/12) (2014).

[2] Public Health England. National Diet and Nutrition Survey: Results from Years 1–4 (combined) of the Rolling Programme (2008/2009 -2011/12) (2014).

[3] Mathers, C. D. & Loncar, D. Projections of global mortality and burden of disease from 2002 to 2030. PLoS Med 3, e442 (2006).

[4] “Sugar Addiction”. Current Opinion In Clinical Nutrition And Metabolic Care, vol 16, no. 4, 2013, pp. 434-439. Ovid Technologies (Wolters Kluwer Health), doi:10.1097/mco.0b013e328361c8b8. Accessed 8 July 2021.

[5] Avena, Nicole M. et al. “Evidence For Sugar Addiction: Behavioral And Neurochemical Effects Of Intermittent, Excessive Sugar Intake”. Neuroscience & Biobehavioral Reviews, vol 32, no. 1, 2008, pp. 20-39. Elsevier BV, doi:10.1016/j.neubiorev.2007.04.019. Accessed 8 July 2021.

[6] Berk, Michael et al. “So Depression Is An Inflammatory Disease, But Where Does The Inflammation Come From?”. BMC Medicine, vol 11, no. 1, 2013. Springer Science And Business Media LLC, doi:10.1186/1741-7015-11-200. Accessed 8 July 2021.

[7] Knüppel, Anika et al. “Sugar Intake From Sweet Food And Beverages, Common Mental Disorder And Depression: Prospective Findings From The Whitehall II Study”. Scientific Reports, vol 7, no. 1, 2017. Springer Science And Business Media LLC, doi:10.1038/s41598-017-05649-7. Accessed 8 July 2021.