Is a 3-Day Fasting Cycle Slowing Your Metabolism?

Metabolism is a complex biological process, and it is not influenced by the frequency of meals or the number of calories consumed per day. Rather, short-term glucose and insulin levels play a key role in this process (keyword: metabolism).

The Role of *HGH* and TSH in Metabolism

When the pituitary gland detects low levels of glucose and insulin, it triggers the secretion of HGH (Human Growth Hormone). This hormone initiates the process of breaking down stored fats for energy while simultaneously reducing the release of TSH (Thyroid Stimulating Hormone), which lowers the metabolic rate. Conversely, when glucose and insulin levels are high, the pituitary gland stops releasing HGH, as there is no need to burn stored fat. Instead, TSH levels rise to utilize the available glucose, since the body can only store a limited amount of it and is very inefficient at converting glucose into fat (keyword: metabolism).

Understanding the Metabolic Effect of Fasting

In periods of low food intake, including even starvation, the human body slows down its metabolism to minimize energy expenditure (keyword: metabolism). When you consume food, your metabolism increases to process it and maintain energy output for your physical activities and the highly energy-demanding brain. Thus, a 72-hour fast can cause your body to slow down its metabolism unless energy demands are met. Walking, especially walking up a steep slope, is a good way to maintain metabolism. Running, although it burns less energy per hour, can still provide a rapid weight loss effect. Panting helps release the byproducts of fat burning (keto state). Therefore, whether you choose to fast for weight loss or to induce autophagy, 72-hour fasting is not always necessary. A fasting period between 16 and 20 hours can achieve similar results. Intermittent fasting works by training the body to adapt to a new energy storage level, maintaining a controllable insulin level, and promoting mild fat burning without significantly lowering the metabolic rate (keyword: intermittent fasting).

Frequent fasting (e.g., weekly 72-hour fasts) may cause some slowing of the metabolism, but it can also be retrained through regular exercise. Engaging in 2 hours of continuous walking, either walking or running, can help keep the metabolism active. Gym work is beneficial, but it mainly focuses on building muscle rather than burning a significant amount of energy, which is more effectively achieved through walking or running. Additionally, activities that move large thigh muscles, such as hiking or stair climbing, increase metabolism, even during periods of low food intake. The heart is also supported by the calf muscles in pumping blood back to the extremities, reducing heart strain.

By understanding the metabolic changes associated with fasting and engaging in regular exercise, you can effectively maintain or even improve your metabolic rate, making the best use of intermittent fasting practices for weight loss and overall health.