7 lessons I learned from spending years trying to improve every aspect of my life

For the last several years, I've attempted to live my life as a human guinea pig and improve every aspect of it.

I've engaged in a series of experiments on my mind and body, some of which have been fruitful, some humiliating failures.

I've tried to understand the world by immersing myself in extraordinary circumstances.

I've also grown a tremendously unattractive beard.

Here are the seven biggest life lessons from my experiments:

1) Be grateful for elevators - and everything else.

From my experiment in living by all the rules of the Bible

For a year, I lived all the rules of the Bible. And I mean all of them. Not just the Ten Commandments, but also the hundreds of other lesser-known rules. The Bible says that you cannot shave the corners of your beard.

I didn't know where the corners were, so I just let the whole thing grow until I had this massive topiary hanging from my chin. (True fact: I spent a lot of time at airport security). I also avoided wearing clothes and mixed fibers and stoned adulterers (though I used pebbles).

After the year, I shaved my beard and put down the pebbles. But I kept many of my biblical practices. One of them? Giving thanks. The Bible says that you should give thanks for everything.

So I did. Literally. I was thankful when I pressed the elevator button and it came to my floor. I got in the elevator and was thankful it didn't plummet to the basement and break my collarbone.

It was a strange way to live. But it was also wonderful, because it changed my perspective. I realized there are hundreds of good things that happen every day that we totally take for granted and we focus on the three or four that go wrong.

2) Stand up straight.

From my George Washington experiment

When George Washington was a young man, he wrote out a list of 110 rules of life (including rule number 2, which is that you should avoid adjusting your private parts in public. Can't argue with that. Though I might have put it a little lower on the list, maybe 8 or 9).

I followed the list for two months to see what our Founding Father could teach me about life.

For one thing, Washington was famous for his amazing posture, almost a parody of good posture: Chest way out, shoulders far back.

I normally have terrible posture. I look like Hominid Number 2 on the evolution charts. But I decided to adopt a Washingtonian posture.

And strangely, my new posture changed the way I felt. I felt more confident, more decisive. When I told my kids to stop licking their placemat, they actually listened.

Turns out George Washington was 250 years ahead of his time. As Harvard Business School professor Amy Cuddy has shown, good posture makes you happier. It raises your testosterone level and lowers your cortisol level.

3) Adapt or die.

From the Encyclopedia Britannica experiment

When I was a kid, my dad started to read the Encyclopedia Britannica. He didn't quite finish. Made it up to the letter B, around Bolivia. So after college, I decided to finish what he began and remove that black mark from our family history.

One big takeaway? Don't stay static in business or life. Successful companies have been adapting - or pivoting (to use a trendy word) - for centuries. Just one example: Thomas Welch was a 19^th century minister who avidly opposed alcohol. In the 1860s, he invented his grape juice and called it "Dr. Welch's Unfermented Wine." He wanted churches to use it in communion. It flopped.

A few years later, Welch's son took over abandoned the fake wine idea. He instead marketed the juice as, well, juice. A tasty and refreshing treat. And that is why, today, my sons love juice boxes, despite their father's insistence that it's basically tooth-rotting sugar water.

4) Be radically honest - up to a point.

From my experiment in total truth

A few years ago, I tried a lifestyle called Radical Honesty. This is a movement begun by a Virginia psychologist named Brad Blanton. His idea? Don't lie. But he goes further than that.

He says: Remove the filter between your brain and mouth. Say whatever you're thinking. It's a real-life version of Jim Carrey's Liar, Liar.

In some ways, this was an excruciating experiment. One time, my wife and I bumped into some of her college friends at a restaurant.

They said "We should all get together and have a playdate with our kids." I had to say what was on my mind, which was "You seem nice. But I have no interest in seeing you again. I don't have time to see my actual friends." Horrible. (Though we never did see them again).

But in other ways, Radical Honesty was liberating. You never had to remember lies. You never have to strain your brain creating lies. You have this wonderful freedom from choice.

I now try to practice a version of Radical Honesty. I call it Radical Positive Honesty. I express positive emotions whenever I can, even if it makes me sound dorky or Ned Flanders-ish.

If I'm thinking about an old mentor, I'll call up and say "I just wanted to thank you for being such an inspiring role model." The recipient is usually a bit taken aback. But in the end, I think they like it. So thank you Brad Blanton.

5) Ask yourself, "What would Odysseus do?"

From my experiment in trying to be as healthy as possible

In the Homer's epic, his hero Odysseus had a strategy. Odysseus knew that his boat was going to pass by the notorious sirens, those mythical creatures whose song was so alluring, sailors jumped off their ships and drowned.

So Odysseus planned ahead. He stuffed his ears with wax. And he had his sailors tie him to the mast. It worked.

I'm a huge fan of the Odysseus strategy. I'm not into bondage, so I don't tie myself up, but I do like the idea of outsmarting yourself. You have to prepare for your own lapses in willpower.

This is why I try to keep healthy food at eye level and put the cheese puffs high up in the cabinet so I can't see them. It's why I will put my iPhone in a closet so I can get some work done. Or why I use programs like Freedom that stop you from jumping into the alluring Internet ocean.

It's why I once made a deal with my wife: If I ate any more sugary dried mangos, she would give $100 of my money to an organization. And not just any organization: The American Nazi party. That was hugely effective. There was no way I was going to eat another dried mango after that.

6) Talk to yourself.

From my experiment in Unitasking

I did an experiment in which I tried to avoid multitasking for a month. One surprisingly helpful strategy: I narrated my own life. When I was alone or on the street, I'd talk out loud to myself, ignoring the stares of suspicious passersby.

Among the benefits: It forces you to live a mindful life. You are present. "I am walking through Central Park. I'm in the middle of a crowded city, and I can barely see the buildings. Amazing."

And it helps balance your emotions. The very act of saying "I'm angry" makes you less angry. It lights up the language centers in the brain, which are in the more evolved cerebral cortex, which allows you to better control yourself. So go ahead, mutter away.

7) It's easier to act your way into a new way of thinking than think your way into a new way of acting.

From all of my experiments

The above quote is from Millard Fuller, the founder of Habitat for Humanity. I love that quote. A shorter way of saying it: "Fake it till you make it." But I prefer the 22-word version.

This strategy was a key to all my experiments. It's astounding how much our behavior affects our thoughts.

The Bible told me to be compassionate. So I forced myself to visit a sick friend in the hospital even though I hated setting foot in hospitals.

The strategy helped me trick my mind. When I was at the hospital, and my brain thought, "Well, I'm visiting a friend in the hospital, I must be compassionate." And I became a little more compassionate.

When writing my book on health, I would wake up each morning in despair - how can I write this book? It's too big a topic. I'll never finish on time.

My solution? I pretended to be confident. I'd call up doctors to set up interviews. I'd email my publisher and suggest we have a huge launch party and serve kale martinis.

Eventually my brain caught up with my actions and I became more confident.