The discussion here is about diet and nutrition, not medical intervention. Understanding how modern diets cause insulin resistance is not about lacking empathy or focusing only on theory. It is about recognizing the biological reality that applies to everyone, regardless of circumstance. Insulin resistance develops not because people fail to enjoy life but because the modern food environment promotes constant exposure to refined carbohydrates, excessive omega-6 oils, and processed foods that keep insulin elevated throughout the day.
The claim that a diet must include unhealthy foods to be maintainable misses the point. A sustainable diet should support long-term metabolic health, not short-term comfort. A low-carb or LCHF diet is not a restriction but a corrective approach that helps restore insulin sensitivity disrupted by modern eating habits. Once metabolic balance is regained, flexibility in food choices naturally improves without triggering harmful blood sugar or insulin surges.
Exercise and sleep are important, but they cannot undo the metabolic strain of a high-carb, omega-6-heavy diet.
In support of what you said, prepare for a wall of text. ( in a good way)
The Randle Cycle, also known as the glucose-fatty acid cycle, describes the reciprocal relationship between the metabolism of glucose and fatty acids. It's a crucial regulatory mechanism at the cellular level, primarily in the mitochondria of our muscles.
In essence, it states: The presence of one fuel inhibits the oxidation (burning) of the other.
1. High Carbohydrate Availability (High Insulin): When you eat a carbohydrate-rich meal, blood glucose rises, triggering insulin release. Insulin facilitates glucose entry into cells and promotes its oxidation for energy. Crucially, the process of glucose breakdown (glycolysis) increases the production of a molecule called malonyl-CoA. Malonyl-CoA acts as a powerful signal that inhibits Carnitine Palmitoyltransferase-1 (CPT-1), the enzyme responsible for shuttling fatty acids into the mitochondria to be burned. Result: Fat is locked away in storage (adipose tissue) and cannot be used for fuel.
2. High Fatty Acid Availability (Low Insulin): In a fasted state or on a low-carbohydrate diet, insulin is low, and fatty acids are released from fat stores. High levels of circulating fatty acids are taken up by cells and oxidized for energy. The byproducts of this fat oxidation (specifically Acetyl-CoA and NADH) actively inhibit the key enzymes of glycolysis (Pyruvate Dehydrogenase and Phosphofructokinase). Result: Glucose oxidation is blocked, and glucose is largely spared for the brain (which can use ketones) or for glycolytic pathways.
The Critical Takeaway: The body is designed to be metabolically "monogamous." It prefers to burn one primary fuel at a time. Trying to burn both simultaneously—as happens on a high-carb, high-fat diet—creates metabolic competition and inefficiency.
Connecting the Randle Cycle to the Optimal Animal-Based Diet
The proposed optimal diet—high in animal fats/protein and low in carbohydrates—is perfectly engineered to work in harmony with the Randle Cycle, promoting metabolic health and flexibility.
1. It Eliminates Fuel Competition and Promotes Metabolic Clarity.
· Standard Modern Diet (High-Carb/High-Fat): This diet, rich in sugars, grains, and vegetable oils, constantly floods the system with both glucose and fatty acids. The Randle Cycle explains the metabolic chaos this creates:
· After a meal, high insulin from carbs shuts down fat burning. The dietary fat you just ate has nowhere to go but into storage (de novo lipogenesis) or, worse, into ectopic fat deposits in the liver and muscles, contributing to insulin resistance.
· The body is constantly switching between fuels inefficiently, a state described as "metabolic confusion." This is a primary driver of hyperinsulinemia and Type 2 Diabetes.
· Optimal Animal-Based Diet (High-Fat/Low-Carb): This diet provides a single, dominant fuel source: fat.
· Low carbohydrate intake means low baseline insulin and low malonyl-CoA.
· With the CPT-1 "gate" wide open, the abundant dietary and body fats flow effortlessly into the mitochondria to be oxidized for energy.
· There is no glucose to compete. The Randle Cycle is operating in its clean, preferred "fat-burning mode." This state of metabolic clarity is the foundation for stable energy and hormonal balance.
2. It Fosters Metabolic Flexibility, Not Rigidity.
This is a crucial point. The goal is not to never burn glucose, but to have the flexibility to burn whatever fuel is available.
· On the optimal diet, your primary fuel is fat. When you do consume carbohydrates (e.g., from seasonal fruit), the body can handle them. The insulin response will be sharp and appropriate, the glucose will be used or stored as glycogen, and then, because the diet is fundamentally low-carb, the body will seamlessly transition back to fat oxidation once the glucose is cleared.
· In contrast, a chronic high-carb diet destroys metabolic flexibility. The system is so saturated with glucose and insulin that the fat-burning machinery is permanently suppressed. The individual becomes a "sugar-burner," reliant on constant carbohydrate intake and vulnerable to energy crashes and hunger when glucose dips.
3. It Aligns with Our Evolutionary Fuel Source.
From an evolutionary perspective, the Randle Cycle makes perfect sense. Our ancestors did not have access to constant carbohydrate intake. Their metabolic survival depended on being able to efficiently burn fat (from animal kills) for energy during periods of fasting or scarcity.
· The Randle Cycle ensured that when game was caught and fat was consumed, the body could immediately and efficiently use it as its primary fuel, without competition from a non-existent constant glucose stream.
· The ability to inhibit glucose oxidation when fat was abundant was an advantage, sparing glucose for the few tissues that absolutely required it.
Conclusion
The Randle Cycle is not merely a biochemical curiosity; it is a foundational principle of human metabolism. The standard high-carbohydrate modern diet directly violates this principle, forcing the body into a state of constant fuel competition that leads to metabolic dysfunction.
The optimal animal-based diet, rich in animal fats and low in carbohydrates, is biochemically congruent with the Randle Cycle. It:
· Minimizes insulin and malonyl-CoA, unlocking the body's ability to burn fat as its primary, clean-burning fuel.
· Eliminates metabolic competition, providing "fuel clarity" and preventing the fat-storage signaling caused by mixed macronutrient intake.
· Restores true metabolic flexibility, allowing the body to efficiently utilize both dietary fats and occasional carbohydrates as nature intended.
In short, the Randle Cycle provides the detailed biochemical "why" behind the metabolic superiority of a low-carb, high-fat, animal-based diet.
