Ketogenic Therapy: Why Is It Beneficial for the Brain?
The brain is an energy-hungry organ. Although it accounts for only around 2% of our body weight, it uses approximately 20% of the body's energy.
The brain is remarkably adaptable and can run on two main sources of fuel: glucose and ketones (made from fat). Which fuel is used most depends on the kinds of food we eat, eating patterns, physical activity, and periods without food. This ability to switch between fuel sources is known as metabolic flexibility - a hallmark of good metabolic health that creates optimal-functioning cells, not just in the body, but the brain, too.
Nutritional ketosis is not a new or unnatural state. Ketones are produced naturally during fasting, a ketogenic diet and during pregnancy. However, in today's world of frequent eating, constant snacking and highly processed, starchy, sugary foods, many people rarely give their bodies the opportunity to access stored energy and produce ketones.
Ketones: An Alternative Fuel for the Brain
Ketones provide the brain with an efficient additional source of energy. This may be particularly beneficial when the brain's ability to use glucose becomes less efficient, something that can occur alongside insulin resistance and chronically elevated blood sugar levels.
Researchers increasingly recognise that metabolic health and brain health are closely connected. Emerging evidence suggests that disruptions in blood sugar regulation, insulin signalling and energy metabolism may influence mood, cognition and long-term neurological health.
When in nutritional ketosis, much of the body is fueled by ketones (made from fat), while the liver produces all the glucose needed for the relatively small number of glucose-dependent cells through gluconeogenesis, using components derived from fat and protein.
More Than Just Fuel
Ketones do far more than simply provide energy. They:
Support mitochondrial function (the cell's energy-producing structures)
Alter neurotransmitter balance (increase GABA, the calming neurotransmitter - and decrease glutamate, an excitatory neurotransmitter)
Improved brain cell signalling and gene expression
Reduce oxidative stress (damage done by oxidants - unstable compounds in tissues)
Positively influence inflammatory pathways
These processes are increasingly recognised as important contributors to healthy brain function and resilience.
Many people who follow a well-formulated ketogenic diet report improved mental clarity, concentration, long-lasting energy and better mood or emotional resilience.
An interesting area of research relates to the insulin-degrading enzyme (IDE), which is involved in both insulin metabolism and the clearance of amyloid-beta proteins in the brain. Amyloid-beta is a natural metabolic by-product in the brain, but excessive accumulation is associated with Alzheimer's disease. Some researchers have proposed that chronically elevated insulin levels may compete for this enzyme's activity, potentially affecting amyloid clearance. This growing area of research has led some scientists to refer to Alzheimer's disease as "type 3 diabetes", reflecting the potential role of impaired insulin signalling and glucose metabolism in brain health.
Are We Eating Too Often, and the Wrong Foods?
Research suggests that many people now eat far more frequently than previous generations. Frequent eating leaves little opportunity for the body to switch from using incoming dietary energy to accessing stored energy reserves, meaning many people spend very little time producing ketones.
As our understanding of metabolic health evolves, many experts are questioning whether constant eating is necessary or beneficial. In today's food environment, where ultra-processed, sugary and starchy foods are readily available, eating is often driven by stress, boredom, habit or emotions, and more importantly - dysregulated hunger and satiety hormones, rather than true hunger. Processed, starchy and sugary foods disrupt the body's natural hunger and satiety signals, making it difficult to recognise when we truly need to eat. In contrast, nutrient-dense, whole foods, including those commonly found in a well-formulated ketogenic diet, support natural appetite regulation.
The relationship between metabolic health and brain health is a fascinating and rapidly evolving area of research. Whilst there is still much to learn, the evidence to date suggests that supporting the body's ability to use energy efficiently may have far-reaching benefits.
Whether through a low-carbohydrate approach, ketogenic therapy or simply improving metabolic flexibility, nutrition can be a powerful tool for supporting long-term brain health.
Read FAQs about a ketogenic diet here.
This article is for educational purposes only and should not be considered medical advice. Ketogenic therapy should be individualised and undertaken with appropriate professional support, particularly for those with existing medical conditions or taking medication.
