How Fasting May Reshape Metabolism and Activate Immune Defenses Against Cancer
Udumbara
.
How Diet Can Strengthen Immune Cell Function
To support their rapid growth, cancer cells consume a large amount of glucose and generate energy through anaerobic respiration, but they also rely on nutrients such as fatty acids and amino acids. Therefore, Liao suggested that adjusting the diet to influence metabolism could be a feasible strategy. Even though it might not be able to completely block cancer cells from obtaining sugar, fatty acids, and proteins—because these are also nutrients required by normal cells—modifying the proportion, content, and timing of the diet can help the body activate its own defense mechanism.During dietary adjustments that limit energy supply, normal cells have the ability to undergo cellular breakdown or autophagy—a process that allows cells to clean out waste and repair themselves. These are especially beneficial attributes for enhancing immune cell function. In contrast, cancer cells are more susceptible to damage because of problems with their mitochondria—the parts of cells that produce energy—and they cannot adapt easily to metabolic stress, making them more likely to be eliminated during chemotherapy, radiotherapy, or immunotherapy.
Liao said that simulated fasting is not a total fast. It provides essential nutrients and calories—around 500 to 600 per day—to put the body into a regenerative state. During this time, normal cells can use ketone bodies and glycogen as energy sources to maintain normal function, while cancer cells cannot survive due to the lack of alternative energy sources. This makes radiotherapy and chemotherapy more effective and causes fewer side effects.
Fasting Induces Autophagy
Autophagy, the body’s built-in cellular cleanup system, can be triggered when cells encounter stressful environments such as nutrient deficiency. Liao said that in addition to simulated fasting, there are two main types of fasting that can promote autophagy:Liao also shared his experience with intermittent and simulated fasting. He said that the “168” fasting routine is easier to maintain. When he feels extreme hunger during the process, he typically relieves it by drinking sugar-free coffee, green tea, or sugar-free soy milk.
When simulating fasting, he chooses scientifically proven products as meal replacements. Liao said that after reducing his calorie intake to 600 calories on the first day, he felt quite hungry and tired. This happened because of a sudden drop in blood sugar. The body then had to switch to using fat or glycogen for energy—a slower process. Hunger and tiredness are especially pronounced when he needs to engage in mental or physical activities at the same time, so he drinks plenty of water to maintain his metabolism. On the third day, his body gradually adapted, and his weight dropped by about 2 kilograms due to reduced water and fat consumption.
Limiting Asparagine—A Potential Strategy to Fight Cancer
A Taiwanese study published in March in Nature Metabolism found that cancer can be fought by limiting specific nutrients. Researchers successfully reduced or even eliminated tumors in nasopharyngeal cancer patients by reducing asparagine in the body.Asparagine is a nonessential amino acid found in abundance in meat, fish, eggs, nuts, and other foods. The human body can also synthesize it. Asparagine is needed by both immune cells and cancer cells to support growth and metabolic activity.
In analyzing the research, Liao noted that limiting asparagine involves two key aspects. On the one hand, it deprives cancer cells of nutrients and inhibits their function. On the other hand, limiting asparagine causes immune cells to change how they process energy, becoming more efficient and effective at targeting cancer. This promotes the generation of memory T cells, which are better able to recognize tumor characteristics and assist killer T cells in attacking cancer cells.
As asparagine was first isolated from asparagus, there are concerns that eating asparagus could promote cancer cell proliferation or enhance cancer cell survival. Liao said that after asparagine from food is digested in the intestine, its original form no longer exists. Instead, it is the asparagine synthesized by the human body that affects the growth of cancer cells and immune cells.
Liao said that the key is to study how to use drugs to block cancer cells from using asparagine. However, research in this area is still in its early stages. The side effects of such nutrient-restricting drugs may also damage normal cells, so there is still a long way to go before this approach reaches clinical application.
In the end, he reminded everyone that due to individual differences and specific conditions, it is important to consult a qualified physician for personalized treatment plans and prescriptions.
.
