For a growing number of Australians, anxiety, depression, panic, and brain fog do not respond fully to talk therapy or medication alone. One of the most overlooked reasons is blood sugar. When glucose rises and falls outside a healthy range, the brain interprets those swings as threat, and the nervous system responds with the same physical symptoms people describe as anxiety, low mood, or “feeling foggy and disconnected.”
This page sits inside Goodsky’s broader metabolic psychiatry framework. It explains how blood sugar dysregulation drives mental health symptoms, what the research shows, and how our outpatient mental health program assesses and supports this stream of biology across Australia. It is educational and does not replace assessment by a registered psychiatrist, GP, or psychologist.
Why Blood Sugar Is a Mental Health Issue, Not Just a Metabolic One
Mood, attention, and anxiety are downstream of how the brain is fuelled. The brain runs almost entirely on glucose under normal conditions, and it cannot store its own supply. When blood glucose rises sharply after a high-glycaemic meal, then crashes, the brain perceives an energy crisis and triggers adrenaline and cortisol. Those stress hormones produce shakiness, internal agitation, palpitations, irritability, and a sense of urgency. For a nervous system already sensitised by trauma, poor sleep, or chronic stress, that physiological cascade can feel indistinguishable from a panic attack.
The Australian Context: A Metabolic Backdrop Most People Do Not See
Blood sugar dysregulation in Australia is no longer a fringe issue. According to the Australian Bureau of Statistics National Health Measures Survey (2022 to 2024 release), 6.6% of Australian adults had diabetes confirmed by fasting plasma glucose, and a further 4.9% were classed as being at high risk based on HbA1c. That is roughly one in nine adults already in, or approaching, a dysregulated range.
The Australian Institute of Health and Welfare reports that almost 1.2 million Australians were living with type 2 diabetes in 2021, with about 125 new diagnoses every day. Case numbers tripled between 2000 and 2021.
These figures matter for mental health because the link between glycaemic dysregulation and mood is bidirectional. Depression roughly doubles the risk of developing type 2 diabetes, and people living with type 2 diabetes have approximately twice the prevalence of depression compared with the general population (Joseph & Golden, 2017, Annals of the New York Academy of Sciences). For many Australians, blood sugar is quietly contributing to symptoms long before any formal diabetes diagnosis.
How Blood Sugar Dysregulation Drives Anxiety
The clearest mechanism is reactive hypoglycaemia. After a high-glycaemic meal, insulin rises rapidly to clear the glucose surge. In some people, the overshoot drops blood sugar below the brain’s preferred operating range. The brain interprets that drop as danger, and the adrenal glands release adrenaline and cortisol to mobilise stored glucose.
The symptoms produced by that adrenaline release are physically identical to a panic attack: racing heart, tremor, sweating, dizziness, derealisation, and a sense of impending dread. A foundational study by Gorman et al. (1984) in the American Journal of Psychiatry documented this overlap directly. More recently, Gutiérrez García & Contreras (2023) in Neuropsychobiology concluded that anxiety is an early sign of acute hypoglycaemia, appearing before more obvious physical markers.
For people whose anxiety is partly driven by glucose swings, the experience of waiting for the “next attack” can itself become a trigger. Stabilising blood sugar does not remove the psychological work that anxiety requires, but it removes one of the physiological accelerants.
How Blood Sugar Dysregulation Drives Depression
The link to depression is slower-burning and works through insulin resistance rather than acute glucose drops. Insulin resistance is the state in which cells respond less readily to insulin, requiring the pancreas to produce more of it to keep blood glucose in range. It exists on a spectrum that begins long before type 2 diabetes appears on a blood test.
Two of the largest studies in this field both link insulin resistance to depression risk and severity:
- Watson et al. (2021) in the American Journal of Psychiatry followed a Dutch cohort and found that three different markers of insulin resistance, including triglyceride to HDL ratio, fasting glucose, and waist circumference, predicted the incidence of major depressive disorder.
- Mansur et al. (2021) in JAMA Psychiatry found that insulin resistance was associated with both depression severity and remission status, supporting the idea of a metabolic endophenotype within depression.
A useful review by Watson et al. (2018) in Neuropharmacology summarises insulin resistance as a modifiable target in depressive disorders. None of this evidence claims that insulin resistance causes depression in every case. It does indicate that for a meaningful subset of people, insulin biology is part of the picture, and improving it is associated with better outcomes.
Brain Fog, Concentration and Brain Insulin Resistance
Cognitive symptoms, including poor concentration, slow word-finding, and the feeling of being “behind glass,” are common features of both anxiety and depression. They also overlap with what researchers call brain insulin resistance, in which insulin signalling within the brain itself becomes impaired.
Kullmann et al. (2016) in Physiological Reviews describes brain insulin resistance as sitting at the crossroads of metabolic and cognitive disorders, with effects on memory, eating behaviour, and executive function. Bauermeister et al. (2023) in BMJ Mental Health reported, in the PREVENT cohort of middle-aged adults, that insulin resistance, age, and depression each contribute independently to cognitive performance.
For people who describe their depression as “I cannot think clearly,” addressing blood sugar may be a more relevant intervention than another round of cognitive behavioural therapy alone. For broader context, see our piece on anxiety and the overactive nervous system.
The Cortisol and Blood Sugar Loop
Blood sugar regulation is not separate from the stress system; it is part of it. Cortisol’s primary job is to raise blood glucose by mobilising stored energy. When cortisol is chronically elevated, fasting glucose tends to drift upward and insulin sensitivity drops. When blood sugar falls, cortisol surges to compensate. Over time the two systems become locked in a feedback loop that intensifies both anxiety and fatigue.
The bidirectional review by Joseph & Golden (2017) maps this triangle of stress, depression, and type 2 diabetes through the hypothalamic pituitary adrenal (HPA) axis. For people with a trauma history, this matters: a nervous system that is already biased toward threat has a smaller margin for glucose-driven adrenaline release.
What We Look For: Testing for the Blood Sugar Signal
A result inside the standard reference range is not the same as a result inside a functional therapeutic window. Reference ranges are designed to catch overt disease, not subtle dysregulation that contributes to mental health symptoms.
The markers we expertly examine, with the help of pathology and functional testing partners, include:
- Fasting glucose and fasting insulin, with HOMA-IR calculated for insulin sensitivity
- HbA1c, which reflects average glucose over the prior three months
- Triglyceride to HDL ratio, an indirect marker of insulin resistance
- Glycaemic variability over time, where appropriate
The investigative value of glycaemic variability is supported by Ravona-Springer et al. (2017) in Diabetes Care, which found that each one percent increase in HbA1c standard deviation was associated with a 31% increase in depressive symptoms in elderly adults with type 2 diabetes. An et al. (2023) in Frontiers in Psychiatry extended this in a longitudinal nationwide cohort, and the systematic review by Muijs et al. (2021) in Endocrinology, Diabetes & Metabolism concluded that glucose variability is associated with mood in adults with diabetes.
Standard mental health assessment in Australia rarely includes these markers in any depth. That is one of the distinct gaps our outpatient pathway is designed to close.
Continuous Glucose Monitoring as a Tool for Mental Health
A continuous glucose monitor (CGM) is a small sensor that measures interstitial glucose every few minutes for one to two weeks. Originally developed for diabetes management, it is increasingly used to map glucose responses in non-diabetic populations. For mental health purposes, a CGM lets us see the relationship between meals, sleep, stress, and the appearance of symptoms.
Zhang & McIntyre (2025) in CNS Spectrums reviewed the role of CGM in psychiatric symptom management, supporting its use as a window into the biological side of mood and anxiety. Lin et al. (2024) in Diabetes Research and Clinical Practice found relationships between CGM-derived glycaemic profiles and both anxiety and depression symptoms.
What the Evidence Says About Diet for Mood
Dietary research in mental health is moving faster than most people realise. The most cited Australian study is the SMILES trial by Jacka et al. (2017) in BMC Medicine, a randomised controlled trial run through Deakin University’s Food and Mood Centre. It found that a twelve-week Mediterranean-style dietary intervention produced significantly greater improvements in moderate to severe depression than a social support control, with about a third of the intervention group meeting remission criteria.
The takeaway is not that diet alone cures depression. It is that diet quality, with a focus on whole foods, fibre, healthy fats, and protein, is a biologically relevant lever, and an absence of dietary support is an absence of a highly useful tool. A case report by Aucoin & Bhardwaj (2016) in Case Reports in Psychiatry describes generalised anxiety disorder and hypoglycaemia symptoms improving with dietary modification, illustrating how individualised the response can be.
How Goodsky Addresses Blood Sugar in Our Outpatient Program
Goodsky’s outpatient mental health program is a structured, one-on-one, three to four month pathway delivered remotely across Australia. Blood sugar is one of several biological streams assessed and supported within it, alongside the metabolic psychiatry framework that informs the whole program.
The blood sugar component typically includes:
- A comprehensive functional pathology panel covering fasting glucose, fasting insulin, HOMA-IR, HbA1c, lipid ratios, inflammation markers, and thyroid status.
- Where professionally indicated, a one to two week continuous glucose monitoring window paired with a structured mood and symptom diary.
- Behavioural naturopathy and precision nutrition support to shape meal composition, timing, and sleep around glucose stability.
- Integration with psychotherapy and somatic work so that the physiological foundation supports rather than replaces the psychological work.
For practical, week-by-week guidance on flattening glucose swings at home, see our companion blog on blood sugar and mental health.
When Blood Sugar Work Is Not Enough
Metabolic foundations matter, but they are foundations. Trauma, attachment injury, grief, persistent negative thought patterns, and significant relational disruption do not resolve through better breakfasts alone. The same is true for severe psychiatric illness, suicidality, and conditions requiring medical management.
Goodsky’s program is not appropriate for acute crisis, active suicidal intent, or conditions requiring inpatient psychiatric care. We work alongside, not in place of, registered psychiatrists, GPs, and psychologists. When blood sugar work resolves the physiological noise, the psychological work tends to become more accessible, not less necessary.
Who This Approach Suits
A metabolic-psychiatry-aligned approach to blood sugar tends to suit Australians who:
- Experience anxiety or panic with strong physical components, especially shakiness, palpitations, or symptoms one to two hours after meals.
- Have depression that has not responded fully to talk therapy or medication.
- Describe persistent brain fog, poor concentration, or post-meal energy crashes.
- Have a family history of type 2 diabetes, polycystic ovary syndrome, or metabolic syndrome.
- Are looking for a more thorough biological assessment than standard mental health care typically offers.
- Want a structured, professionally guided pathway rather than self-directed experimentation.
This approach is less suitable for people in acute crisis, those requiring intensive medical management, or those who are not in a position to engage with a multi-month outpatient pathway.
Frequently Asked Questions
Does blood sugar affect anxiety and depression?
Yes, for a meaningful subset of people. Rapid glucose drops can trigger the same adrenaline cascade that produces panic symptoms, and insulin resistance is associated with both depression risk and severity in large studies including Watson et al. (2021) and Mansur et al. (2021). Blood sugar is not the only driver of mental health symptoms, but it is a modifiable one that standard care often overlooks.
What is reactive hypoglycaemia and how does it cause panic-like symptoms?
Reactive hypoglycaemia is a sharp drop in blood glucose after a meal, usually one to two hours later, often triggered by a high-glycaemic load. The drop activates an adrenaline response that produces tremor, palpitations, sweating, dizziness, and a sense of dread—symptoms that are physically indistinguishable from a panic attack.
Can insulin resistance cause depression?
Insulin resistance is associated with higher rates of depression and with poorer remission outcomes, but it is one factor in a multi-causal condition. Literature describes insulin resistance as a metabolic endophenotype of depression, meaning a biological subtype rather than a universal cause. For people whose biology fits this pattern, addressing insulin sensitivity is a reasonable part of a broader recovery plan.
Does Goodsky use continuous glucose monitoring?
When professionally appropriate, yes. A short CGM window, typically one to two weeks, paired with a structured mood diary, can reveal the relationship between glucose patterns and the appearance of anxiety, low mood, or brain fog.
Is this the same as metabolic psychiatry?
Blood sugar regulation is one of several biological systems metabolic psychiatry investigates, alongside mitochondrial function, the gut-brain axis, inflammation, micronutrient status, and the HPA axis. For the full framework, see our metabolic psychiatry in Australia resources.
