A method of intermittent fasting, Alternate Day Fasting (ADF), consists of a 24-hour fasting window that is followed up by a 24-hour non-fasting window.

There has been research (on rats) that suggests that longer and/or extended usages of Alternate Day Fasting could be “detrimental” to one’s heart.  “According to one study, chronic ADF in rats resulted in the development of diastolic dysfunction with diminished cardiac reserves.  The researchers concluded that ‘the deleterious effect of ADF in rats suggests that additional studies on ADF’s effects on cardiovascular functions in humans are warranted,’ stated Fredricks.”

However, while these observations are undeniable, the variables must be recognized.  There has been abundant research that presented the fact that short-term ADF has positive effects on the heart.

So, do these studies contradict? Well, not exactly.

One mound of research is dedicated to the short-term effects on the heart, while the other is dedicated to the long-term.  None of the research contradicts, but both bring about notable variables- For one, the absence and/or lack of studies conducted on humans is ever-so evident in these studies, as well as other studies on ADF.

Additionally, one observation that must be made, is that ADF is only one form of intermittent fasting and the results from these studies don’t apply to all of the methods of intermittent fasting.  “As with other types of fasting, the design of the fast may be the key factor in study outcomes.  For example, research has suggested that intermittent fasting is most beneficial and safest when there are atlas five days of re-feeding with reasonable caloric intake between the periods of time in which the individual is fasting.”

Published in 2011 on rats, this study showed that long-term intermittent fasting leads to an increase in the blood level.  Furthermore, there was another study published in 2010 that showed that rats who were subjected to regular fasts, “mysteriously developed stiff heart tissues which decreased the heart’s ability to pump blood to the body.”  Ultimately, the long-term results of intermittent fasting on humans are somewhat uncertain.  However, it cannot be denied that there are short-term benefits and very possible long-term benefits as well.  “Negative intermittent fasting stories are not as numerous as stories in support of intermittent fasting.”  While examining this statement, the consumer must ask the vital questions- Is this because benefits are inevitably exaggerated and the risks are consequently downplayed?  Or are there truly health benefits as a result of intermittent fasting?  Both may be true, it all depends on the integrity of the producer that is responsible for the news, article, study, research, etc.

Intermittent fasting could have negative effects on those who are underweight.  This is because one of the things that intermittent fasting does is cut your body fat.  However, those who are in shape may still find intermittent fasting beneficial.  This is for one, because of the weight loss aspect, but also because of the many health benefits.  “Additionally, intermittent fasting can be harmful to those who have issues with their blood sugar levels and people suffering from hypoglycemia (abnormally low levels of glucose in the blood) should avoid this plan.”

When starting intermittent fasting, It is important to take into account that during the first week of intermittent fasting, the body will feel week.  This is not because of the lack of nutrients per-se, but rather because of the sudden change of one’s eating lifestyle.



  1. Davidson, John, and Muhammad Usman.  Amazing Health Benefits of Intermittent Fasting.  JD-Biz Corp Publishing, 2013. Print.