One of the primary reasons for the success of humans throughout our existence is our adaptability. Humans have been able to adapt biologically, cognitively and socially, culturally, genetically, and in response to technological changes. If we are placed in a harsh environment, we will develop the necessary tools to survive in that environment, and our body will adjust physiologically to be better suited for this new environment. Now of course many creatures can adapt to changing environments, but nothing really does it as well as we do. Adaptability allows us to survive in diverse environments, allows us to form complex societies, respond to global changes (economically or environmentally), and is a driver of evolution. Adaptability and flexibility builds our resilience towards various stressors, and this superpower extends itself to nutrition and metabolism. Here we will look into the idea of metabolic adaptability and flexibility, and speak to why being more metabolically adaptable could be a key to longevity and better metabolic health.
What Is Metabolic Adaptability?
Metabolic adaptability refers to the ability of an organism to adjust metabolically based on a variety of environmental conditions, dietary intake, and energy demands. Adaptability allows an organism to efficiently manage and utilize different nutrients to maintain homeostasis, support growth, and respond to stressors. Here are some examples of what metabolic adaptability allows:
Energy Utilization
Metabolic adaptability involves switching between different energy sources depending on availability. For example, based on the current norm of getting most of our energy from carbohydrates, the body primarily uses glucose from these carbohydrates to create energy. However, while we are fasting, on a low carbohydrate diet, or on a ketogenic diet, the body shifts to breaking down fats into fatty acids and ketones (ketogenesis) to maintain energy supply.
Adaptation To Dietary Changes
The body can adapt to various styles of eating and utilize whichever macronutrients are predominantly available. This includes metabolizing a high-fat, low-carbohydrate diet, a high-carbohydrate, low-fat diet, and everything in between. The body is able to do this by adjusting enzymatic pathways to optimize the breakdown and synthesis of required molecules. For example, someone on a high-fat, low-carb diet will synthesize (create) more lipase (fat digesting enzymes) than amylase (carbohydrate digesting enzymes) to account for the higher amount of fat. High-fat diets also increase mitochondria content, another adaptation.
Hormonal Regulation
Hormones play a key role in metabolic adaptability. For instance, insulin and glucagon help to regulate blood sugar levels by controlling the uptake of glucose into the cells and the release of glucose from energy stores, respectively. These hormonal changes allow the body to respond dynamically to changes in nutrient availability.
Response To Physical Activity
During increased physical activity, metabolic adaptability allows muscles to switch from using primarily glucose, to increased fatty acid oxidation, especially as glycogen stores become depleted. In most instances this will be seen in endurance sports like distance running, hiking, rowing, swimming, etc, and this shift helps us sustain energy levels throughout long periods of exercise.
Health Implications
Being metabolically flexible is often associated with better overall health, including reduced risk of metabolic diseases like type 2 diabetes mellitus and obesity. Conversely, metabolic inflexibility, where the body struggles to switch between fuel sources efficiently, is linked to various metabolic disorders.
A Deeper Look Into The Health Implications Of Metabolic Flexibility and Inflexibility
Metabolic Flexibility:
- Improved energy efficiency: Efficiently switching between burning carbohydrates and fats ensures that the body can optimize energy production for different activities and conditions, such as resting, and different forms of activity.
- Better weight management: Adequate metabolic flexibility helps in maintaining a healthy weight. It allows the body to more effectively utilize fats and carbohydrates, reducing the likelihood of fat accumulation.
- Enhanced Physical Performance: Athletes with high metabolic flexibility can better manage their energy stores during varied intensities of exercise, which can improve endurance and overall performance.
- Reduced risk of metabolic disorders: Metabolic flexibility is associated with lower risks of developing disorders such as type 2 diabetes, obesity, and metabolic syndrome, as the body can better manage blood sugar levels and insulin sensitivity.
- Improved adaptation to dietary changes: Being metabolically flexible allows the body to adapt more easily to different diets, whether they are high in fats, protein, or carbohydrates, without compromising metabolic health.
- Resilience to fasting and feasting: Metabolic flexibility improves the body’s ability to cope with periods of food abundance and scarcity, maintaining energy production and storage as needed.
Poor Metabolic Flexibility:
- Insulin resistance: Poor metabolic flexibility often leads to difficulty in switching from fat to carbohydrate metabolism, which contributes to elevated insulin levels and eventual insulin resistance, a precursor to type 2 diabetes. Impaired glucose tolerance due to disrupted insulin function is one of the big reasons we should stive for metabolic flexibility.
- Increased fat storage: When the body cannot efficiently switch between burning fat during periods of low carbohydrate intake, it may lead to increased fat storage and weight gain. This depends on a variety of factors, however.
- Reduced exercise tolerance: Poor metabolic flexibility can affect physical performance, leading to early fatigue and less effective utilization of energy sources during exercise.
- Difficulty adapting to dietary changes: Individuals with poor metabolic flexibility may struggle with dietary changes, like going from the standard American diet (SAD) to a ketogenic diet, and will likely experience negative symptoms like low energy, mood swings, and poor cognitive function temporarily.
- Increased risk of metabolic syndrome: Metabolic syndrome is characterized by high blood pressure, high blood sugar, excess fat around the waist, and abnormal cholesterol levels, is more common in individuals with poor metabolic flexibility.
- Chronic inflammation: Poor metabolic flexibility is associated with chronic, low-grade inflammation, which is linked to various chronic diseases like heart disease and cancer.
How Can I Improve My Metabolic Flexibility?
- Adjusting macronutrient intake: There are a few ways to do this. To give two examples, you can do a low carb or ketogenic diet cyclically, to sort of teach your body how to turn fats over more efficiently into energy, or just simply try a week or two consuming less carbs, while consciously eating more fat. Another way to improve metabolic flexibility in a less stressful way, simply eating more balanced meals can do the trick. I think the biggest key here is simply moderation of everything. None of the three big macronutrients are bad, but solely relying on one form of energy can cause our metabolism to become stagnant.
- Intermittent fasting: This has several flavors really, but generally consists of a feeding window and a fasting window. Usually the fasting window should be around 14-16 hours to flip the metabolic switch (glucose to fats) for most individuals, especially when done consistently, but this varies.
- Regular Exercise: Whether it is short and explosive, or endurance based, exercise can increase mitochondrial density. Mitochondria are a key component to energy metabolism as they help us create cellular energy (ATP) in the electron transport chain (ETC). Having more mitochondria means we will have more cellular energy.
- Consistent sleep: This one is sort of a no brainer, and really deserves a post of its own, but sleep is one of the most important recovery tools we have. If we are not recovering well, our metabolism suffers.
- Hydration: Adequate hydration leads to an increase in cell volume, which boosts cellular signaling in response to insulin, which may help improve insulin sensitivity.
In conclusion, human adaptability extends far beyond surviving in diverse climates or overcoming physical challenges; it deeply influences our metabolic processes, proving crucial for maintaining health and optimizing our bodily functions. Metabolic flexibility, a key aspect of this adaptability, ensures that we can efficiently transition between different energy sources based on dietary intake and physical demands. This capability not only supports everyday health and energy levels but also guards against metabolic diseases and enhances our ability to cope with dietary variations and physical exertion. By fostering our metabolic flexibility, we honor our adaptive heritage and equip our bodies to face the modern world's dietary and environmental challenges. This adaptability is not just a survival mechanism; it's a profound testament to our evolutionary legacy and a cornerstone of our ongoing health and vitality.