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Tonight I'd like to talk to you

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about an experiment I did a few years ago,

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that improved my life in so many ways.

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However, before getting into the details,

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I wanted to take you on a trip,[br]and photography can help us, to Africa,

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to try to understand a bit[br]the context of this whole experiment.

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Just imagine these four hunters

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moving through a typical[br]Savannah scenario.

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They are on the hunt.

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They are following a herd[br]of enormous herbivores, called kudu,

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and specifically a much larger one[br]that left the group.

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They are putting him under pressure.

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The human being evolved[br]for resistance race;

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a race that is not too fast,

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but that can go on for a very long time.

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The hunters are putting him[br]under pressure,

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and the kudu - unlike human beings -

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cannot regulate his body temperature;

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and because he is a large herbivore,

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his intestine does not allow him[br]to breathe correctly on the run.

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The fate of the kudu[br]is unfortunately marked,

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because at some point[br]it will have to stop,

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otherwise its heart would burst[br]due to the rise in temperature.

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So the hunter,

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with just a simple pointed wooden shaft,

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can end the life of this large herbivore.

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Even if this is a cruel scene,[br]it does not happen often.

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It is difficult for the hunters[br]to carry it out.

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Today our guys will take home[br]about 38,000 calories

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to share with the rest of the village,

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women, children[br]and less fortunate hunters,

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for that day.

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I spent ten years in Africa,[br]in Capetown to be precise,

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where I worked in a center[br]for population genetics,

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and together with other researchers,[br]I became passionate

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about the lifestyle[br]of these hunter-gatherers,

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who are still present[br]in different parts of Africa,

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so also in South Africa,[br]the state of Lesotho;

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and Botswana, Namibia and Tanzania.

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And so we often spent time with them

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to try to understand[br]their lifestyle, their eating habits,

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their movement patterns[br]throughout the day.

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We had incredible experiences:

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I remember we used[br]to follow them in the hunt,

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in their gatherings, all day long,[br]maybe a 38-degree hot day,

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with our super technological shoes

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and Camel Bags[br]full of water, mineral salts

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and maybe the latest[br]generation of supplements,

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but it was practically impossible[br]to keep up with them.

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Sometimes we had to sit[br]in the shade of an acacia,

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and while I watched them[br]disappear on the horizon,

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I wondered if they weren't[br]really superior beings,

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I mean really incredibly strong people[br]from all points of view,

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also considering how stressful[br]their daily lifestyle is.

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I then returned to Italy

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and decided to start this experiment,

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because something didn't add up.

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From this slide you can see

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that some agencies, such as FAO,[br]ENSA or the American FDA,

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suggest the correct intake of calories

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to maintain body homeostasis[br]and good health.

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If we look at it,

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everyone will find their range,[br]according to age and sex,

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somewhere around 2,600-2,800 calories.

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As far as I was concerned,[br]something didn't add up.

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While living with them,[br]they didn't have those daily calories.

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Yes, if the hunt was successful,

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surely there were even more than that,

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but it wasn't always the case.

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So I decided to start an experiment[br]that lasted for months.

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I greatly reduced

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the amount of suggested calories.

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I made a food plan

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that got as close as possible[br]to what I had seen

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and I followed it for a while.

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From a hematological perspective,

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I monitored all[br]the parameters that came out,

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taking samples every three - four weeks,

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in a laboratory,

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and trying to see the changes

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in blood glucose, azotemia,[br]cholesterol, creatinine

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and all the other factors[br]that are influenced by diet,

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one way or another.

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Plus, I also tried to monitor[br]how my body changed

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in terms of lean mass, fat mass,[br]visceral fat and body hydration,

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and obviously I kept a daily journal

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to see day by day

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how I was reacting mentally,

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how my moods and energy levels were.

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I carried out this experiment.

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It was not easy at first -[br]my wife knows something about that -

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because moods change very very often,

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energy falls, and so it also has[br]an influence on your work.

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But I wanted to look beyond the horizon;

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I tried to move forward,[br]despite a lot of people said to me,

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"What are you doing?

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You're decreasing your calories[br]and increasing your physical activity:

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that's not good, it's wrong."

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I went further, tried to continue,[br]and after a while something changed.

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I remember it was friday,[br]because I was keeping a journal.

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I woke up,

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and felt an energy[br]I hadn't felt in a long time.

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My sense of smell and taste[br]were completely altered for the better.

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I could feel everything around me[br]in a 360 degrees fashion,

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as though I were experiencing[br]the real "here and now".

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I was not happy,

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so I tried to involve, at the beginning,

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a bunch of crazy friends,

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who said, OK, come on,[br]we're right behind you.

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I also gave them a plan[br]with the same concept:

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lower by 1000 calories[br]their daily nutritional intake.

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And with them I monitored,[br]using specific questionnaires,

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a whole series of parameters.

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Then I went from friends to acquaintances,

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and we really increased in number.

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Some people wanted to try it[br]just for the sake of challenge,

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at least for a while.

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We eventually became so many.

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I collected all this data,

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and although obviously[br]with different timing,

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eventually everything converged

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into the same feelings I had experienced:

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a general sense of well-being and health.

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These are parameters

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that perhaps may not make sense to you,

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but make it clear

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that when the body[br]undergoes caloric stress,

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something happens;

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it is like an awakening, inside our cells,

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of genes that had been hidden and dormant

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for hundreds of thousands of years.

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So I tried to go a little more[br]deeply into the topic,

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and through PubMed ,

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which is a database where you can find

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all the research done[br]by laboratories around the world,

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I looked for ones

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that had somehow studied deeper[br]and for a much longer time,

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the difference between[br]our society's lifestyle

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and that of hunter-gatherer populations

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still in place around the world.

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And there were -

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This is one of the graphs[br]that basically shows

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caloric diversity from plants and animals

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across the different populations.

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Essentially, I found[br]three main differences.

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One is caloric regime;

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another is caloric expenditure,

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the amount of calories burned in a day;

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The third, perhaps most important thing -[br]that struck me so much -

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is the very presence in our society

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of a whole series of degenerative diseases

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that are statistically increasing[br]in the population,

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even in the youngsters -[br]take obesity, for example.

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These diseases are completely unknown

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in these hunter-gatherer populations.

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So I wondered, what if these calories[br]are the real culprit?

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If we look at this graph, 1990 to 2015,

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the caloric intake worldwide[br]has increased exponentially.

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I am one of those[br]who did not raise his hand before,

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when the math teacher[br]asked who was good at it.

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So if we want to, we can do an experiment:

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take out our cell phone,

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and go to the calculator application.

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Ok? Let's put in 1000 calories.

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We multiply that by seven,[br]one for every day of the week,

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and then by four,[br]one for every week in a month.

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And then we go on, by 12,

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and we get to 336,000 -

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Then let's put in 20 years.

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That gets us to six million calories.

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I want to leave you with this thought:

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what if these six million extra calories[br]were the unexpected cause

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for these diseases

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and do not allow us to age[br]in a healthy manner,

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and prevent us to become[br]like those hunters,

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with all that great energy we have?

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Thank you for your attention.

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(Applause)