https://ezra.com/blog/fasting-and-cancer

The link between fasting and cancer continues to be a topic of mass discussion, but does fasting really have an impact in cancer prevention and treatment? 

Cancer care is developing at an exceedingly high rate yet deaths remain high. In fact, cancer (particularly lung cancer) is one of the leading causes of death in the United States. Some of these deaths could be avoidable, with many cancers linked to modifiable risk factors. 

According to the American Society of Cancer, at least 42% of new cancer cases in 2023 were potentially avoidable, with 18% attributable to alcohol, excess body weight, low levels of physical activity, and poor nutritional status. This highlights a potential opportunity to reduce cancer rates and outcomes by promoting healthy lifestyle changes that can lead to a longer and healthier lifespan.

Read on to learn about the connection between fasting and cancer and how it might affect your overall well-being. 

What Do We Mean by Fasting?

Fasting is the practice of abstaining from eating (and sometimes drinking) for a period of time. It focuses on when you eat as opposed to what you eat. Although it has recently grown in popularity, it has been practiced among many cultures and religions for thousands of years.

The role of fasting in health and disease is also not a new concept and has been described in ancient Greece where fasting was advocated by Hippocrates as a method of treating illness.

What Are Different Types of Fasting?

There are three main types of fasting: intermittent fasting, time-restricted feeding, and prolonged fasting. Let’s take a closer look at each one.

Intermittent Fasting

Intermittent fasting involves fasting cycles, which relates to abstaining from eating food on alternate days or periodically. There are many different regimens—for example, the 5:2 diet. This involves a calorie restriction to 25% of normal calorie intake for two non-consecutive days and normal calorie consumption for the remaining five days.

Time Restricted Feeding

This type of fasting involves limiting the consumption of food to a specific period of time. For example, all calories are typically consumed within 4-12 hours. There is no calorie restriction.

Prolonged Fasting

This refers to fasting periods lasting more than 24 hours.

Fasting-Mimicking Diet 

A fasting-mimicking diet (FMD) is slightly different than those listed above. FMD involves a five-day periodic diet that causes the body to enter a fasting mode without complete abstinence from eating. 

FMD is usually a low-carbohydrate, low-protein, and low-calorie diet over 4-7 days. Professor Valter Longo is at the forefront of research into fasting-mimicking diets and their effect on disease processes and longevity. 

The results from a randomized clinical trial carried out by Professor Longo indicated that FMD reduces risk factors and markers associated with aging and disease, although larger studies are required to confirm the findings.

How Is Fasting Different From Calorie Restriction?

Calorie restriction is a type of dietary restriction that refers to a prolonged reduction in average calorie intake without causing malnutrition. There are positive health benefits associated with calorie restriction, including an improvement in insulin sensitivity, reduced inflammation, and a reduction in adipose (fat) tissue.

The CALERIE trial has shown that prolonged moderate caloric restriction improves cardio-metabolic risk factors, such as high blood pressure and insulin sensitivity. Furthermore, the American Cancer Society has found that caloric restriction may reduce the risk of cancer (and explains the underlying molecular mechanisms involved). That said, calorie restriction is difficult to maintain, thus leading to a growing interest in fasting, particularly intermittent fasting.