This also had the effect of reducing the formation of cataracts, heart and kidney deterioration, and tumor formation! Senescent cells are cells that have essentially run out of telomeres, and are no longer behaving how they’re supposed to. Fasting is also known to have the effect of helping to clean up these cells (a process called autophagy). Additionally, senescent cells, which increase with old age, are dangerous because they secrete pro-inflammatory cytokines that damage other nearby cells thus accelerate the aging process.