Our brain is amazing. Its functions expand further than you or I could possibly imagine. But, even though it is the most intricate piece of engineering ever curated, we decide to belittle it, reducing its impact to abstract ideas of emotion and mentality.

For example, if you want to lose the most weight in the quickest amount of time, become a chess grandmaster who plays in daily tournaments. Even though these individuals sit at a table for 12-plus hours a day, they burn up to 6,000 calories a day. The immense mental concentration and stress that floods their brains during matches causes similar physiological responses to physical exercise. Studies of their heart rate, breathing tempo, blood pressure, and even muscle contraction skyrocket their metabolic rate, leading to this caloric expenditure. But how is this possible given they sit at a table all day, not moving an inch?

Even though it represents 2% of our body weight, our brain consumes 20% of the body’s available energy. However, unlike our skeletal muscle, this organ prefers to get its energy from glucose, the carbohydrate-derived nutrient. But, as you may realise, the brain of people who are on a ketogenic diet (sub-50g carbs) is not shutting down, so this is not the whole story. Essentially, if you enter a low carb diet, your brain has the ability to switch to ketones. However, this does not mean the brain prefers it. In fact, it switches purely due to energy management, or in other words, to survive when glucose is scarce.

But our current understanding suggests that ketones are less efficient in their ATP yield for molecules compared to glucose. For instance, acetoacetate yields about 22 ATP molecules when fully oxidised, which is less than the 38 derived from glucose. Also, the production of ketones from fatty acids in the liver requires extensive energy, and the transport of ketones to peripheral tissues and the brain has high energy costs. Although this may be the case, over time, the body adapts to using ketones more effectively by reducing the energy cost during transportation; specifically, the brain can upregulate MCTs to increase ketone uptake.

I understand that some of that might not have made too much sense, but essentially, ketosis is not as productive as glucose within the diet. We currently believe this is just an evolutionary adaptation and not something we always had. Whether we were meant to be keto, or meant to eat glucose, it is hard to tell. Current historical understanding points to ketosis as part of our innate being, but that’s slightly irrelevant now.

Anyway, back to the point. Our brain, at its current evolutionary standpoint, thrives on glucose. When I learnt this, it confused me slightly, especially given the forceful push of ketogenic diets. But they do have some good points, just not in relation to brain and bodily function. Firstly, ketones are derived from the fat cells within our body. This means you can consider your daily energy to be directly reducing your fat percentage. Also, the fact that ketogenic diets help fight insulin resistance, which is especially important for type 2 diabetics.

However, the issue with most ketogenic studies is the sample. Most samples contain people who have eaten the S.A.D. (Standard American Diet) for most of their lives. So it is no wonder that we see better neurotransmitter regulation, fat reduction, and gene expression. But there are some significant issues with it. For me, I would label ketogenic diets as anti-metabolic due to the impact it has on your metabolic rate, especially on vital endocrine systems for fat loss and general wellbeing.

Therefore, the core understanding I have of a dietary approach is to ensure the body feels in a safe and plentiful environment, ensuring it is out of starvation reach. This idea is called ‘pro-metabolic’ and focuses on how our bodies downregulate their metabolic rate to save energy when it is scarce. Essentially, when energy is not readily available, our body slows down its thyroid and sex hormone function. It takes what it considers to be ‘least important’ and reduces its energy, leading to what we call a slow metabolism. But providing our body with an abundance of energy from carbs and fats allows the body to come out of its power-saving mode and into its ‘pro-metabolic’ stance.

Depriving our body of glucose and fructose inhibits the function of the thyroid and similar endocrine systems. For example, on a keto diet, our thyroid levels tank. Essentially, our T3 and TSH are indirectly involved in fat loss due to their impact on overall metabolic rate. If this system crashes, the enzymes that break down triglycerides in fat cells are not produced, and even the few that are, are far less efficient.

This is why I am extremely pro-carbohydrate, especially pro-sugar. Unlike current trendy diets, a lifestyle high in sugar and fat not only gives the brain its constant energy supply but ensures every single endocrine system functions at full blast, aiding in fat loss, neurological function, and neurotransmitter production.

However, the question that arises is the difference between glucose and fructose. As a diet such as this involves a lot of fruit sugar, which is fructose, and our brain cannot use it as an energy source, it raises a relevant point.

This is where high glucose sugar sources come into play. Foods naturally high in glucose should be a staple in every diet. The main one that comes to mind is honey, known not only for its antioxidants and nutrient profile but also because it contains mostly glucose in a sweet, delicious, and beneficial substance. Also, almost all dried fruit, but dates are my absolute favourite. With about 25g of sugar per 100 calories, dates provide an extreme number of vitamins, minerals, and antioxidants, making them, alongside raw honey, one of the most nutritious substances on the planet. Alongside this, they contain less serotonin than other fruits, but that’s for a different article.

Overall, while the brain’s adaptability to use ketones showcases its evolutionary ability, the underlying message is clear: for optimal health, particularly in terms of metabolic efficiency and endocrine function, a diet rich in glucose and natural sugars appears to be most beneficial. This doesn’t mean shunning fats; in fact, it means quite the opposite. Instead, it advocates for embracing carbohydrates and making them a staple in your diet. However, this is not an implication to consume ultra-processed breads and doughs. Rather, this piece informs on the importance of including high levels of sugar, fat, and glucose.