Tonight I'd like to talk to you
about an experiment I did a few years ago,
that improved my life in so many ways.
However, before getting into the details,
I wanted to take you on a trip, and photography can help us, to Africa,
to try to understand a bit the context of this whole experiment.
Just imagine these four hunters
moving through a typical Savannah scenario.
They are on the hunt.
They are following a herd of enormous herbivores, called kudu,
and specifically a much larger one that left the group.
They are putting him under pressure.
The human being evolved for resistance race;
a race that is not too fast,
but that can go on for a very long time.
The hunters are putting him under pressure,
and the kudu - unlike human beings -
cannot regulate his body temperature;
and because he is a large herbivore,
his intestine does not allow him to breathe correctly on the run.
The fate of the kudu is unfortunately marked,
because at some point it will have to stop,
otherwise its heart would burst due to the rise in temperature.
So the hunter,
with just a simple pointed wooden shaft,
can end the life of this large herbivore.
Even if this is a cruel scene, it does not happen often.
It is difficult for the hunters to carry it out.
Today our guys will take home about 38,000 calories
to share with the rest of the village,
women, children and less fortunate hunters,
for that day.
I spent ten years in Africa, in Capetown to be precise,
where I worked in a center for population genetics,
and together with other researchers, I became passionate
about the lifestyle of these hunter-gatherers,
who are still present in different parts of Africa,
so also in South Africa, the state of Lesotho;
and Botswana, Namibia and Tanzania.
And so we often spent time with them
to try to understand their lifestyle, their eating habits,
their movement patterns throughout the day.
We had incredible experiences:
I remember we used to follow them in the hunt,
in their gatherings, all day long, maybe a 38-degree hot day,
with our super technological shoes
and Camel Bags full of water, mineral salts
and maybe the latest generation of supplements,
but it was practically impossible to keep up with them.
Sometimes we had to sit in the shade of an acacia,
and while I watched them disappear on the horizon,
I wondered if they weren't really superior beings,
I mean really incredibly strong people from all points of view,
also considering how stressful their daily lifestyle is.
I then returned to Italy
and decided to start this experiment,
because something didn't add up.
From this slide you can see
that some agencies, such as FAO, ENSA or the American FDA,
suggest the correct intake of calories
to maintain body homeostasis and good health.
If we look at it,
everyone will find their range, according to age and sex,
somewhere around 2,600-2,800 calories.
As far as I was concerned, something didn't add up.
While living with them, they didn't have those daily calories.
Yes, if the hunt was successful,
surely there were even more than that,
but it wasn't always the case.
So I decided to start an experiment that lasted for months.
I greatly reduced
the amount of suggested calories.
I made a food plan
that got as close as possible to what I had seen
and I followed it for a while.
From a hematological perspective,
I monitored all the parameters that came out,
taking samples every three - four weeks,
in a laboratory,
and trying to see the changes
in blood glucose, azotemia, cholesterol, creatinine
and all the other factors that are influenced by diet,
one way or another.
Plus, I also tried to monitor how my body changed
in terms of lean mass, fat mass, visceral fat and body hydration,
and obviously I kept a daily journal
to see day by day
how I was reacting mentally,
how my moods and energy levels were.
I carried out this experiment.
It was not easy at first - my wife knows something about that -
because moods change very very often,
energy falls, and so it also has an influence on your work.
But I wanted to look beyond the horizon;
I tried to move forward, despite a lot of people said to me,
"What are you doing?
You're decreasing your calories and increasing your physical activity:
that's not good, it's wrong."
I went further, tried to continue, and after a while something changed.
I remember it was friday, because I was keeping a journal.
I woke up,
and felt an energy I hadn't felt in a long time.
My sense of smell and taste were completely altered for the better.
I could feel everything around me in a 360 degrees fashion,
as though I were experiencing the real "here and now".
I was not happy,
so I tried to involve, at the beginning,
a bunch of crazy friends,
who said, OK, come on, we're right behind you.
I also gave them a plan with the same concept:
lower by 1000 calories their daily nutritional intake.
And with them I monitored, using specific questionnaires,
a whole series of parameters.
Then I went from friends to acquaintances,
and we really increased in number.
Some people wanted to try it just for the sake of challenge,
at least for a while.
We eventually became so many.
I collected all this data,
and although obviously with different timing,
eventually everything converged
into the same feelings I had experienced:
a general sense of well-being and health.
These are parameters
that perhaps may not make sense to you,
but make it clear
that when the body undergoes caloric stress,
something happens;
it is like an awakening, inside our cells,
of genes that had been hidden and dormant
for hundreds of thousands of years.
So I tried to go a little more deeply into the topic,
and through PubMed ,
which is a database where you can find
all the research done by laboratories around the world,
I looked for ones
that had somehow studied deeper and for a much longer time,
the difference between our society's lifestyle
and that of hunter-gatherer populations
still in place around the world.
And there were -
This is one of the graphs that basically shows
caloric diversity from plants and animals
across the different populations.
Essentially, I found three main differences.
One is caloric regime;
another is caloric expenditure,
the amount of calories burned in a day;
The third, perhaps most important thing - that struck me so much -
is the very presence in our society
of a whole series of degenerative diseases
that are statistically increasing in the population,
even in the youngsters - take obesity, for example.
These diseases are completely unknown
in these hunter-gatherer populations.
So I wondered, what if these calories are the real culprit?
If we look at this graph, 1990 to 2015,
the caloric intake worldwide has increased exponentially.
I am one of those who did not raise his hand before,
when the math teacher asked who was good at it.
So if we want to, we can do an experiment:
take out our cell phone,
and go to the calculator application.
Ok? Let's put in 1000 calories.
We multiply that by seven, one for every day of the week,
and then by four, one for every week in a month.
And then we go on, by 12,
and we get to 336,000 -
Then let's put in 20 years.
That gets us to six million calories.
I want to leave you with this thought:
what if these six million extra calories were the unexpected cause
for these diseases
and do not allow us to age in a healthy manner,
and prevent us to become like those hunters,
with all that great energy we have?
Thank you for your attention.
(Applause)