Introduction:
Intermittent fasting diets are very popular in the last few years, due to their clinical effectiveness on subjects’ weight loss¹. They are consisted of periods of eating alternating with periods of fasting². Intermittent fasting is a generally safe type of diet, because of effects on health-related outcomes and lifestyle adherence providing, while it produces few neurological, hormonal, gastrointestinal and other metabolic adverse effects³.

Methods:
Applied summarization of current evidence of the efficacy of intermittent fasting to decrease cancer risk, complications and induced biomarkers. In this aspect, many scientific databases, e.g., Google Scholar, PubMed, Google Trends, and Scopus, were comprehensively searched using relative words to identify the existing in vivo and in vitro evidence, as well as clinical trials.

Results:
Intermittent fasting may be beneficial for patients at risk for colorectal cancer because it induces autophagy, a very important process of cellular remodeling and organelle quality control^4,5, which improves the in vivo inhibition of autophagy-competent tumors’ growth, by chemotherapy⁶. Intermittent fasting sensitizes tumors to chemotherapy and protects normal cells, including hematopoietic stem and immune cells, from its toxic side effects⁷. In addition, it increases the levels of bone marrow lymphoid progenitor cells and cytotoxic CD8(+) tumor-infiltrating lymphocytes, leading to major delay in breast cancer and melanoma progression⁷. Finally, intermittent fasting reduces chronic, low-grade inflammation, which increases the risk for many cancer types⁸.

Conclusions:
Intermittent fasting diet may be a protective factor against cancer risk, inhibiting many types of cancer. There are both well-known and not well-known pathophysiological mechanisms beyond these effects, however, well-designed clinical trials for longer study periods are intensely recommended.