Fasting

Fasting: Turn On the Self-Repair System in Your Body

In a 1999 peer-reviewed study published in the American Journal of Physiology, the concept of “metabolic flexibility” examined how skeletal muscle selects between fuel sources in lean versus obese individuals. Insulin resistance, obesity and type 2 diabetes are largely diseases of metabolic inflexibility. A metabolically flexible body can shift between burning glucose and burning fat, depending on what is available.

A study in 2008 identified the impaired capacity for fuel switching as a core mechanism underlying these conditions. A metabolically inflexible body is stuck. It reaches for sugar even when fat is abundant, directly tying the body’s failure to complete the metabolic switch to the accumulation of intramyocellular lipid (fat inside muscle cells).

The science is clear on what restores metabolic flexibility: deliberate, extended periods without food… AKA fasting.

What Happens When You Stop Eating

The metabolic shift from sugar-burning to fat-burning does not happen instantly. When autophagy begins the body works through its available glucose first. Glycogen stores in the liver and muscle are depleted progressively. At around 12 hours without food a transition begins. You reach a threshold where blood glucose and insulin levels drop low enough to activate fat oxidation and initiate ketone production.

Ketones (beta-hydroxybutyrate or BHB) are not a byproduct of starvation. Ketones are an alternative fuel system, more efficiently metabolized per unit of oxygen than glucose, and with notable neuroprotective properties. Research published on the mechanisms of the ketogenic state has shown that BHB crosses the blood-brain barrier and serves as a direct fuel source for neurons, with patients frequently reporting improved cognitive clarity during fasting periods in the range of 12–16 hours.

Alongside the shift to fat metabolism, two hormonal events deserve Denyabetic™ attention.

Growth Hormone

Growth hormone is the primary hormonal driver of tissue repair, fat mobilization, and the preservation of lean muscle mass during caloric deprivation. It is not a supplement. It is endogenous — produced by your own pituitary gland — and fasting is among the most reliable physiological triggers for its release. One landmark study documented a 5-fold increase in males and a 14-fold increase in females during a 24-hour fast.

Ghrelin Hormone

Ghrelin, the hunger hormone, decreases during extended fasting. While this seems counterintuitive it’s well-documented. The neurological experience of hunger does not escalate indefinitely as fasting continues — for most people, it peaks and then recedes as the body adapts to running on fat and ketones.

Fasting for Beginners

1. Choose an 8-hour eating window that best fits your schedule. Eat between 11am and 7pm or 12pm and 8pm. This will give you 16 hours of fasting daily.

2. Black coffee in the morning is fine for most people. Add MCT oil to get you to ketosis faster.

3. Once comfortable, do one 24-hour fast per week. Eat your evening dinner. Skip eating until the next evening dinner, break that 24-hour fast with protein. 30 grams of protein activates muscle growth signals. Always eat protein first.

This page references peer-reviewed scientific literature for informational purposes. It is not medical advice. Consult your physician before making changes to your diet or fasting routine.