Fasting Every Other Day

Fasting for long periods can put off many… Good news: according to a University of Florida
research published in Rejuvenation Research, alternating a day of caloric restriction with a
day spent “celebrating” would bring some of the benefits of fasting.

In mice, fasting increases life expectancy and limits age-related diseases. During fasting,
certain proteins, Sirtuins, are produced which play a role in increasing life expectancy.
Sirtuins would be activated by the presence of oxygen free radicals, and could, therefore, be
inhibited by the presence of antioxidants. The researchers studied the effect of intermittent
fasting on oxidative stress, genes related to aging and metabolism. For 3 weeks, 24 people
alternated 1 day during which they consumed 25% of their caloric intake and 1 day during
which they consumed 175% of their caloric intake. For a man, this was equivalent to 650
calories one day, then 4,550 calories the next day. To test the effect of antioxidant
supplementation, participants were asked to include vitamin C and vitamin E.

At the end of the 3-week period, the researchers found that beneficial sirtuins such as SIRT3
and SIRT1 tended to increase. The authors of this work found that intermittent fasting caused
a slight increase in SIRT3, a well-known gene that promotes longevity and is involved in the
cell's protective responses. On the other hand, antioxidant supplementation could limit this
increase. Other studies have also shown that antioxidants can counterbalance the effects of
fasting or exercise. Proteins like SIRT3 are activated by oxidative stress when there are more
free radicals produced than the body can neutralize. But low levels of free radicals can be
beneficial, for example when the body is under stress, such as during fasting. The researchers
also found that intermittent fasting decreased plasma insulin levels, which means that this diet
could have a protective effect against diabetes. In addition, participants adhered well to this
diet and found it quite tolerable: they did not observe any change in weight or side effects.
Therefore, alternating fasting with a hearty meal would provide some of the benefits of
fasting, but the addition of antioxidant supplements could offset these benefits. Fasting shares
many biological commonalities with the ketogenic diet.

Complete Fasting Over Several Days in a Row

It can be practiced over long periods, ranging from 24 hours to several days, as proposed in
the case of fasting hikes, where total immersion makes it possible to better manage the
period. These long periods of fasting require preparing the body before starting the full week
of restriction, and also gradually reintegrating the food. Personally, I have never tried this
type of long fast, but I recently met a couple, who carry out once a year, a week of fasting, in
a specific context. They are very satisfied with the experience of these one-week fasting
sessions. Of course, you should drink at will during this period, preferably water or herbal
teas.

Partial Fasting

It consists of reducing caloric intake, i.e. significantly reducing dietary intake. During this
partial fast, which generally takes place over 21 days, some foods are to be avoided, such as
ultra-processed foods (I share here the 8 good reasons to reduce this type of food), caffeine,
animal products. This type of fasting proposes to remove the foods I mentioned above and to
consume mostly fruit, vegetables, oilseeds… In short, this fasting is like a way of eating
healthy, which can still remind some people of a certain form of detox. This diet is very
popular in the United States.