The human body has evolved over thousands of years to efficiently derive energy from various sources. While glucose has long been recognized as the body’s chief energy currency, powering our every thought, movement, and physiological process, recent research is spotlighting ketones as a potent, alternative energy reserve. This shift in perspective is reshaping our understanding of metabolism, endurance, and overall health. 

Primarily known for their role in the ketogenic diet, ketones are more than just a fuel source; they represent an evolutionary adaptation that helped our ancestors survive during times of famine. As we venture further into this topic, we’ll uncover the multifaceted role of ketones and how they’re revolutionizing our approach to wellness and nutrition.

Glucose As Fuel


Glucose is a simple sugar derived from the carbohydrates we consume. When we eat foods like starchy vegetables, fruits, and grains, our bodies break down these carbohydrates into glucose, which then enters our bloodstream. The pancreas releases insulin, which helps transport glucose into cells where it is either used for immediate energy or stored for later use.

Glucose is a quick and readily available source of energy. It powers our brain, muscles, and other organs, fueling daily activities and exercise, however, glucose also comes with certain limitations. Our bodies can only store a limited amount of glucose in the form of glycogen, and any excess is converted into fat for long-term storage. Additionally, relying solely on glucose as fuel can lead to spikes and crashes in energy levels, often leaving us feeling fatigued and hungry.

Ketones—An Alternative Source of Energy


Ketones, on the other hand, are small molecules produced in the liver when the body breaks down fats for energy in the absence of glucose. This process is known as ketogenesis, and it typically occurs when carbohydrates are restricted or during prolonged fasting periods. The three primary ketones produced are beta-hydroxybutyrate (BHB), acetoacetate, and acetone.

Ketones are used for fuel in the same way that glucose is used for fuel, but they are utilized in slightly different metabolic pathways depending on the body’s energy needs at a given time. The liver breaks down fatty acids into ketones, which are then released into the bloodstream and transported to the body’s tissues. The cells in the body can use ketones for energy by converting them into a form of ATP (adenosine triphosphate), which is the primary energy source for the body’s cells.

The brain and nervous system can also use ketones for fuel, particularly during times of glucose scarcity, as they cannot directly utilize fatty acids for energy. In fact, studies have shown that ketones may be a more efficient source of energy for the brain compared to glucose. (1)

Benefits Of Using Ketones As Fuel

Ketones have several advantages as an energy source, such as being a more stable and consistent fuel source than glucose, producing fewer Reactive Oxygen Species (ROS) than glucose metabolism, and preserving muscle tissue by reducing the need for glucose breakdown. They can also:

  1. Promote Weight Loss and Fat Burning—Adopting a ketogenic diet, which promotes the production of ketones, has been associated with effective weight loss and fat burning. By restricting carbohydrates and relying on stored fat as fuel, the body can enter a state of ketosis, where ketone levels rise, leading to increased fat oxidation.
  2. Stabilize Energy Levels— Unlike glucose, which can cause energy spikes and crashes, ketones provide a more stable and sustained source of energy. This steady supply can lead to improved endurance during physical activities and reduced feelings of fatigue.
  3. Enhance Brain Function— Research indicates that ketones may have the ability to improve cognitive function. Some studies indicate that individuals in a state of ketosis report better concentration, memory, and mental clarity. (2) This can be particularly beneficial during periods of work that require sustained attention and focus. Ketones have also been shown to have neuroprotective effects. This has been of particular interest in conditions such as Alzheimer’s disease, where glucose uptake in the brain is impaired. Ketones can influence the levels of neurotransmitters like GABA and glutamate, which helps with maintaining a balance between excitation and inhibition in the brain and is crucial for normal brain function.
  4. Improve Athletic Performance— Ketones have a higher energy yield per unit of oxygen consumed compared to glucose, which can lead to improved endurance and reduced fatigue during prolonged physical activities. Furthermore, ketones exhibit anti-inflammatory properties that might aid in faster recovery and reduced muscle soreness post-exercise. Their potential to spare glycogen stores can also be advantageous for endurance athletes by delaying the onset of glycogen depletion. Another benefit is reduced lactate production, which often triggers muscle fatigue. Additionally, ketones exhibit anti-catabolic properties, protecting muscle breakdown during prolonged exercise. 
  5. Offer Potential Health Benefits— Ketones have shown promise in various health conditions, including epilepsy management, where they can reduce seizure frequency; neurodegenerative disorders, potentially slowing disease progression; and specific cancers, possibly inhibiting tumour growth. (3) (4) As research progresses, these findings underscore the importance of understanding ketone metabolism and its potential therapeutic applications.

Considering these potential benefits, how can you optimize your body to utilize ketones as fuel?

Ketones as Fuel

Follow a Ketogenic Diet—The ketogenic diet is known for encouraging metabolic flexibility and fat loss. This high-fat, moderate-protein, and low-carbohydrate eating plan encourages your body to switch from relying on glucose to utilizing ketones for energy. The typical macronutrient breakdown for a ketogenic diet is approximately 70-75% of calories from fat, 20-25% from protein, and only 5-10% from carbohydrates.

The goal is to drastically reduce your carbohydrate intake to around 20-50 grams per day. Foods to focus on include avocados, nuts and seeds, fatty fish, healthy oils (coconut oil, olive oil), and non-starchy vegetables. Be cautious of hidden carbohydrates in processed foods and aim to eat whole, nutrient-dense options.

Incorporate Intermittent Fasting—Intermittent fasting (IF) is another approach to encourage ketone production and utilization. By extending the fasting period between meals, your body depletes its glucose stores and starts producing ketones. One popular method is the 16/8 approach, where you fast for 16 hours and eat within an 8-hour window each day. During the fasting period, your body will turn to its fat stores for energy, leading to ketosis. Combining IF with a low-carb or ketogenic diet can amplify the benefits of both approaches and enhance ketone production even further.(5)

Supplement With Exogenous Ketones—These supplements are formulated to increase the levels of ketones in the body, putting you in a state of ketosis. Please note that the use of exogenous ketones is not a ‘quick fix’ to aid in fat loss. When taking ketone supplements, the body will use the exogenous ketones (rather than the endogenous ketones the body produces in the absence of glucose) as fuel first. These supplements are primarily used for cognitive support and athletic performance. They are available as powders, capsules, and drinks.

Exogenous ketones can be found in two primary forms: ketone salts and ketone esters. Ketone salts are a combination of beta-hydroxybutyrate (BHB) bound to other minerals such as sodium, calcium, and magnesium. Ketones are naturally slightly acidic, and when combined with sodium, it helps to buffer this acidity. Additionally, ketones tend to have a diuretic effect, causing the body to excrete salt, potassium, calcium, and magnesium. The inclusion of sodium in these products serves to restore the lost salts due to this process; however, ketone salts have been shown to be less effective than ketone esters for raising ketone levels, often requiring higher dosages. (6) Because they are bound to other minerals, higher dosage can not only raise sodium levels, but the presence of these minerals can then affect the bioavailability of the ketone itself. This can lead to potential side effects like gastrointestinal distress in some people. Ketone salts are often less expensive and have a more pleasant taste than ketone esters, but again, are not as effective in raising ketone levels without consuming higher amounts. I recommend Prüvit for Ketone salts, you can purchase them HERE.

Ketone esters, on the other hand, are pure BHB molecules that are bound to a ketone precursor and are more bioavailable than ketone salts. This means that a greater proportion of the esters are absorbed into the bloodstream upon ingestion. Ketone esters don’t rely on ion channels for absorption as salts do, leading to more efficient and faster uptake.

Once in the liver, ketone esters are broken down to release BHB directly into the bloodstream. In contrast, the BHB in ketone salts has to be dissociated from the mineral ion before utilization. This extra step can slow the release and utilization of BHB from salts compared to esters.

While they may not be as palatable as ketone salts, ketone esters are typically available in liquid form and can be consumed directly or added to drinks. Ketones can also be useful for pre-workout supplementation as they can increase endurance and stamina during exercise, making them a desirable option for athletes and fitness enthusiasts. I recommend HVMN for Ketone ester you can find it HERE.

Please note that more is not better regarding ketone levels and supplementation, so it is important to monitor your levels. Research supports that the sweet spot for ketosis is a blood level of ketones between 1 mmol/L-2.5 mmol/L. (7) 

Ketone Considerations

When tapping into ketones, there are some considerations to keep in mind:

  • Stay Hydrated and Get Enough Electrolytes—When entering ketosis through fasting, you may experience increased water loss and depletion of essential electrolytes like sodium, potassium, and magnesium. Ensuring adequate hydration and consuming electrolyte-rich foods or supplements can help prevent symptoms like headaches, muscle cramps, and fatigue that can occur during the initial phase of ketosis.
  • Exercise Regularly—Physical activity can help your body utilize ketones more efficiently. Engaging in regular exercise, especially aerobic exercises like walking, jogging, or cycling, can enhance ketone utilization and support overall metabolic health.
  • Monitor Your Ketone Levels—To gauge your progress and ensure you’re effectively utilizing ketones as fuel, be sure to measure your ketone levels. There are various ways to do this, such as through blood, urine, or breath ketone meters. Monitoring your ketone levels can help you make adjustments to your diet and lifestyle to maintain a state of ketosis. This is vitally important for those with diabetes, as blood sugar levels can drop significantly with a reduction in carbohydrate intake. It is best to consult with your healthcare provider prior to starting a ketogenic diet. 

Whether you’re interested in diving deep into a ketogenic lifestyle or looking for ways to improve brain health and physical performance, the study of ketones has opened new avenues for understanding our metabolism. While glucose will always play a foundational role, the myriad benefits of ketones, from weight loss to enhanced cognitive function, showcase the breadth and depth of our body’s capability to source energy. Adequate exercise, occasional fasting, and an overall good diet with an emphasis on healthy fats all help your body to be metabolically flexible and use ketones when necessary.

Remember, the journey to optimal health is a marathon, not a sprint. As always, make informed decisions, and enjoy the ride toward a healthier and more energized you!

In-text References

  1. Jensen NJ, Wodschow HZ, Nilsson M, Rungby J. Effects of Ketone Bodies on Brain Metabolism and Function in Neurodegenerative Diseases. Int J Mol Sci. 2020 Nov 20;21(22):8767. doi: 10.3390/ijms21228767. PMID: 33233502; PMCID: PMC7699472.
  2. Altayyar M, Nasser JA, Thomopoulos D, Bruneau M Jr. The Implication of Physiological Ketosis on The Cognitive Brain: A Narrative Review. Nutrients. 2022 Jan 25;14(3):513. doi: 10.3390/nu14030513. PMID: 35276871; PMCID: PMC8840718.
  3. Barañano KW, Hartman AL. The ketogenic diet: uses in epilepsy and other neurologic illnesses. Curr Treat Options Neurol. 2008 Nov;10(6):410-9. doi: 10.1007/s11940-008-0043-8. PMID: 18990309; PMCID: PMC2898565.
  4. Poff AM, Ari C, Arnold P, Seyfried TN, D’Agostino DP. Ketone supplementation decreases tumor cell viability and prolongs survival of mice with metastatic cancer. Int J Cancer. 2014 Oct 1;135(7):1711-20. doi: 10.1002/ijc.28809. Epub 2014 May 14. PMID: 24615175; PMCID: PMC4235292.
  5. Park S, Zhang T, Wu X, Yi Qiu J. Ketone production by ketogenic diet and by intermittent fasting has different effects on the gut microbiota and disease progression in an Alzheimer’s disease rat model. J Clin Biochem Nutr. 2020 Sep;67(2):188-198. doi: 10.3164/jcbn.19-87. Epub 2020 Mar 20. PMID: 33041517; PMCID: PMC7533860.
  6. Omori NE, Woo GH, Mansor LS. Exogenous Ketones and Lactate as a Potential Therapeutic Intervention for Brain Injury and Neurodegenerative Conditions. Front Hum Neurosci. 2022 Apr 28;16:846183. doi: 10.3389/fnhum.2022.846183. PMID: 36267349; PMCID: PMC9577611.
  7. Gershuni VM, Yan SL, Medici V. Nutritional Ketosis for Weight Management and Reversal of Metabolic Syndrome. Curr Nutr Rep. 2018 Sep;7(3):97-106. doi: 10.1007/s13668-018-0235-0. PMID: 30128963; PMCID: PMC6472268.
Brain HealthKetones: The Body’s Alternative Energy Source Explained
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