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Composed: Mar 13, 2023

Author: Autumn

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Fasting - are there groups who should not fast?

People on health journeys or who are interested in longevity often want to know about fasting and whether or not it's something they should do. And if it is something they should do, for how long?

Fasting - are there groups who should not fast?

And, those are all very good and legitimate questions.

To answer, my mind wonders how fasting (famine) has historically affected the populations and how. Meaning, do certain genders or certain age groups survive famine better than others? And there is data on both age and gender when it comes to survivability in times of famine.


There is data on the percentages of death by age group during times of famine. Percentages of death only give us a big picture. This data cannot tell us how our individual bodies will respond. It's only a piece of a larger puzzle and we shouldn't take it as anything more than that. That said, it is data we can use to help us make an informed decision about whether or not fasting might be appropriate for us.

  • The percentage of death in people aged 0 (less than 1 year old) to 39 decreased during times of famine.
  • The percentage of death in people aged 40-59 increased from 9.8% to 18.7% during times of famine.
  • The percentage of death in people aged 60+ increased from 57.1% to 68% during times of famine.

This is not relative risk, this is the actual incidences of death. So, that means that compared to times of normal access to food, people age 40 and over died in higher numbers. Whereas people under 40 experienced less death during times of famine than during normal times of food availability.


Another confounder is gender. Women survive times of famine at a higher rate (more women survive than men).

A famine in Sweden in 1772 and 1773 caused by crop failures meant that the life expectancy for males plummeted to 17.15 years and 18.79 for females. That's very young! Life expectancy was teen years during this famine. And women still lived longer.

During the famous Irish potato famine (1845-1849), life expectancy dropped by about the same amount for both sexes, 38 years. Women had a life expectancy of 22.4 years and men 18.7 years.

There were a number of regions for which this study collected and analyzed data. Without getting into all of it too much, the conclusion was that the largest advantages of women over men during crisis were as follows:

  • In Ukraine, a difference of almost 50%
  • In Liberia, a difference of 33%
  • In Ireland, a difference of 20%
  • In other populations, the relative advantage was 12% or smaller

Other Considerations

There are, of course, many other considerations that might be important for determining whether fasting is an appropriate intervention. Depending on our hormonal health, fasting may be helpful or it may be harmful. Depending on our mindset, fasting may be something we should avoid. For example, whether we're fasting as a way to improve our health or as a way to punish ourselves for indulging or to "jumpstart" weight loss. "Jumpstart" is a big buzzword around fasting that really has no meaning. There's no jumpstarting and our focus really should be on health, not losing "weight". Our body fat percentage is also a factor.


If all this information feels overwhelming or confusing, it is certainly not my intent to overwhelm or confuse anyone. Instead, I just want to present some information that demonstrates how complex fasting really is.

There are some very popular social media influencers who will try and tell you that fasting is the cure for everything. Fasting is good for everyone and everyone should be doing it, they will say.

I just want to say, that is not necessarily true. Yes, humans have mechanisms in place that are initiated during times of famine to help us survive and even thrive (as we see in the under-40 age group). The processes of apoptosis and autophagy that are initiated in the absence of food are fascinating. And nothing I'm saying here is intended to make anyone think they should or should not fast. It's just a discussion of considerations.

Often, those who are saying it's good for everyone and sharing their own experiences and success stories, are in those age groups that I named that have decreased incidences of death during times of famine.

Their experiences may not be the same as yours or mine.