# The Mathematics of Obesity

Carson Chow is an investigator at the National Institute of Diabetes and Digestive and Kidney Diseases, where he tries to figure out why 1 in 3 Americans are overweight. He’s an MIT-trained mathematician who is using his background to pinpoint why the obesity rate in America is so high (and will likely keep increasing). His interview in The New York Times is a good read:

Why would mathematics have the answer?

Because to do this experimentally would take years. You could find out much more quickly if you did the math.

Now, prior to my coming on staff, the institute had hired a mathematical physiologist, Kevin Hall. Kevin developed a model that could predict how your body composition changed in response to what you ate. He created a math model of a human being and then plugged in all the variables — height, weight, food intake, exercise. The model could predict what a person will weigh, given their body size and what they take in.

However, the model was complicated: hundreds of equations. Kevin and I began working together to boil it down to one simple equation. That’s what applied mathematicians do. We make things simple. Once we had it, the slimmed-down equation proved to be a useful platform for answering a host of questions.

What new information did your equation render?

That the conventional wisdom of 3,500 calories less is what it takes to lose a pound of weight is wrong. The body changes as you lose. Interestingly, we also found that the fatter you get, the easier it is to gain weight. An extra 10 calories a day puts more weight onto an obese person than on a thinner one.

Also, there’s a time constant that’s an important factor in weight loss. That’s because if you reduce your caloric intake, after a while, your body reaches equilibrium. It actually takes about three years for a dieter to reach their new “steady state.” Our model predicts that if you eat 100 calories fewer a day, in three years you will, on average, lose 10 pounds — if you don’t cheat.

Another finding: Huge variations in your daily food intake will not cause variations in weight, as long as your average food intake over a year is about the same. This is because a person’s body will respond slowly to the food intake.

More here.

# Change Your Life in Twenty Minutes a Day

Gretchen Reynolds, author of The First 20 Minutes: Surprising Science Reveals How We Can Exercise Better, Train Smarter, Live Longer, explains how you can change your life in just twenty minutes a day:

The first 20 minutes of moving around, if someone has been really sedentary, provide most of the health benefits. You get prolonged life, reduced disease risk — all of those things come in in the first 20 minutes of being active.

Two-thirds of Americans get no exercise at all. If one of those people gets up and moves around for 20 minutes, they are going to get a huge number of health benefits, and everything beyond that 20 minutes is, to some degree, gravy.

That doesn’t mean I’m suggesting people should not exercise more if they want to. You can always do more. But the science shows that if you just do anything, even stand in place 20 minutes, you will be healthier.

I haven’t read Gretchen’s book, but I am putting her philosophy to use in 2012. My advice: start at just five minutes a day and build up to twenty (or more). It might seem like an insurmountable obstacle in the beginning, which is understandable, but you’ll get there with practice…

# The Record Frequent Fliers

The Los Angeles Times has an interesting article on Steven Rothstein and Jacques Vroom, who are above and beyond what one would consider frequent fliers. Both men bought tickets that gave them unlimited first-class travel for life on American Airlines. Each had paid American more than \$350,000 for an unlimited AAirpass and a companion ticket that allowed them to take someone along on their adventures. Both agree it was the best purchase they ever made, and their life hasn’t been the same ever since they bought the golden ticket.

In the 2009 film, Up in the Air, the loyal American business traveler played by George Clooney was showered with attention after attaining 10 million frequent flier miles.

Rothstein and Vroom were not impressed.

“I can’t even remember when I cracked 10 million,” said Vroom, 67, a big, amiable Texan, who at last count had logged nearly four times as many. Rothstein, 61, has notched more than 30 million miles.

But all the miles they and 64 other unlimited AAirpass holders racked up went far beyond what American had expected. As its finances began deteriorating a few years ago, the carrier took a hard look at the AAirpass program.

If you’re wondering whether you can still get the AAirpass today, the answer is no. In 2004, American offered the unlimited AAirpass one last time, in the Neiman-Marcus Christmas catalog. At \$3 million, plus a companion pass for \$2 million more, not one sold.

# Bloomberg Billionaires Index

With Facebook set to IPO on May 18, with the share price set in the \$28 to \$35 range, Bloomberg has now updated its Billionaire List to reflect Mark Zuckerberg’s wealth at \$17.6 billion.

It’s kind of ridiculous, but this billionaire index is updated daily. For instance, here are today’s top 40 wealthiest people according to Bloomberg:

NAME EST. NET WORTH CTRY \$ CHG DAILY % CHG YTD
1. Carlos Slim Helu \$ 75.0 billion MEX \$ 65.5 M 21.7
2. William “Bill” Henry Gates III \$ 63.2 billion USA – \$ 394.8 M 12.7
3. Warren E. Buffett \$ 45.4 billion USA \$ 12.2 M 6.1
4. Ingvar Kamprad \$ 42.5 billion SWE – \$ 570.0 M 14.6
5. Bernard Arnault \$ 42.2 billion FRA \$ 234.2 M 19.6
6. Amancio Ortega Gaona \$ 38.3 billion SPN \$ 716.3 M 9.8
7. Lawrence “Larry” Joseph Ellison \$ 37.2 billion USA – \$ 377.0 M 12.8
8. Charles De Ganahl Koch \$ 35.5 billion USA \$ 119.7 M 5.7
9. David Hamilton Koch \$ 35.5 billion USA \$ 119.7 M 5.7
10. Eike Fuhrken Batista \$ 31.7 billion BRA – \$ 84.6 M 40.8
11. Sheldon Gary Adelson \$ 25.0 billion USA – \$ 576.9 M 26.6
12. Christy R. Walton \$ 24.7 billion USA – \$ 35.2 M – 1.3
13. Li Ka-Shing \$ 24.6 billion CHN – \$ 169.1 M 11.0
14. Stefan Persson \$ 24.0 billion SWE \$ 379.8 M 10.2
15. Liliane Bettencourt \$ 23.8 billion FRA \$ 53.2 M 17.7
16. Jim C. Walton \$ 23.4 billion USA – \$ 6.9 M 0.1
17. David K.R. Thomson \$ 23.2 billion CAN – \$ 157.2 M 8.5
18. Samuel “Rob” Robson Walton \$ 23.0 billion USA – \$ 6.8 M 0.2
19. Michele Ferrero \$ 22.6 billion ITA – \$ 111.3 M 7.4
20. Alice L. Walton \$ 22.4 billion USA – \$ 6.9 M – 0.2
21. Karl Albrecht \$ 22.0 billion GER \$ 466.9 M – 1.6
22. George Soros \$ 22.0 billion USA – \$ 13.6 M 3.7
23. Mukesh D. Ambani \$ 21.8 billion IND – \$ 444.7 M 1.9
24. Jeffrey “Jeff” Bezos \$ 21.4 billion USA – \$ 95.4 M 30.5
25. Alwaleed Bin Talal Al Saud \$ 20.5 billion SAU 0 18.2
26. Lee Shau Kee \$ 19.5 billion CHN – \$ 20.3 M 13.0
27. Alisher Usmanov \$ 19.3 billion RUS \$ 38.4 M 10.8
28. Cheng Yu Tung \$ 19.1 billion CHN \$ 87.6 M – 4.9
29. Lawrence “Larry” E. Page \$ 18.9 billion USA \$ 73.3 M – 3.9
30. Sergey Brin \$ 18.8 billion USA \$ 71.7 M – 3.8
31. Georgina “Gina” Hope Rinehart \$ 18.7 billion AUS – \$ 144.8 M – 7.5
32. Alberto Bailleres Gonzalez \$ 18.6 billion MEX – \$ 212.2 M 7.9
33. Rinat Akhmetov \$ 18.1 billion UKR – \$ 72.1 M 25.8
34. Lakshmi N. Mittal \$ 18.0 billion IND – \$ 227.7 M – 14.7
35. Iris Fontbona \$ 17.7 billion CHL – \$ 538.1 M 0.7
36. Mark Elliot Zuckerberg \$ 17.6 billion USA – \$ 2,900.0 M – 2.2
37. Azim Premji \$ 16.3 billion IND \$ 97.0 M 1.5
38. Jorge Paulo Lemann \$ 15.8 billion BRA \$ 20.8 M 28.8
39. Vladimir Lisin \$ 15.8 billion RUS – \$ 231.7 M 6.3
40. Steve Ballmer \$ 15.4 billion USA – \$ 38.3 M 17.5

Mark Zuckerberg is number 36 on the list, well ahead of Steve Ballmer.

# The Compounding Returns of Intelligence

Stephen Cohen, co-founder of Palantir, in a conversation with Peter Thiel and Max Levchin:

We tend to massively underestimate the compounding returns of intelligence. As humans, we need to solve big problems. If you graduate Stanford at 22 and Google recruits you, you’ll work a 9-to-5. It’s probably more like an 11-to-3 in terms of hard work. They’ll pay well. It’s relaxing. But what they are actually doing is paying you to accept a much lower intellectual growth rate. When you recognize that intelligence is compounding, the cost of that missing long-term compounding is enormous. They’re not giving you the best opportunity of your life. Then a scary thing can happen: You might realize one day that you’ve lost your competitive edge. You won’t be the best anymore. You won’t be able to fall in love with new stuff. Things are cushy where you are. You get complacent and stall. So, run your prospective engineering hires through that narrative. Then show them the alternative: working at your startup.

(via Dustin Curtis)

# Stephen King on Taxes

In an expletive-filled post, Stephen King says he wants to pay more taxes. King also explains:

Most rich folks paying 28 percent taxes do not give out another 28 percent of their income to charity. Most rich folks like to keep their dough. They don’t strip their bank accounts and investment portfolios. They keep them and then pass them on to their children, their children’s children. And what they do give away is—like the monies my wife and I donate—totally at their own discretion. That’s the rich-guy philosophy in a nutshell: don’t tell us how to use our money; we’ll tell you.

And here is Stephen King’s message to Mitt Romney:

I don’t want you to apologize for being rich; I want you to acknowledge that in America, we all should have to pay our fair share. That our civics classes never taught us that being American means that—sorry, kiddies—you’re on your own. That those who have received much must be obligated to pay—not to give, not to “cut a check and shut up,” in Governor Christie’s words, but to pay—in the same proportion. That’s called stepping up and not whining about it. That’s called patriotism, a word the Tea Partiers love to throw around as long as it doesn’t cost their beloved rich folks any money.

Fun read, even if you disagree with King’s arguments.

# The New International Terminal at Atlanta’s Hartsfield-Jackson International Airport

The new international terminal at Hartsfield-Jackson International Airport in Atlanta will open on May 16, 2012. The Atlanta Journal-Constitution has some details about the “dry run” that took place to test the terminal:

More than 1,600 volunteers streamed into the new \$1.4 billion complex bright and early for the dry run. Hundreds had signed up to participate within hours of the airport’s call for helpers in March.

Many were eager to get a sneak peek at the gleaming 1.2 million square-foot terminal and 12-gate concourse — and give some constructive criticism.

The airport gave each volunteer a trip itinerary and script, which they used to get to the new terminal off I-75, check in for a flight, get a fake boarding pass and check bags, pass through security, report to a gate and go through boarding.

Arriving test passengers went through Customs and immigration checks and claimed bags at the new terminal. They were also directed to look for restrooms, duty-free shops, concessions, the information desk, baggage office, taxi stand, shuttles or other amenities.

The terminal is almost four years in the making and comes with a \$1.4 billion price tag. The 1.2 million square foot terminal and concourse will facilitate direct flights to 45 countries

I think the biggest benefit of the new international terminal will be the elimination of the need for arriving Atlanta-bound travelers to recheck bags upon arrival (and having to go through security after clearing Customs).

Still, it’s amazing the huge turnout this practice run had. One person interviewed in the story has been following the terminal for ten years and took a vacation day from work to participate.

# Your Parents Don’t Want What Is Best for You

Charles Wheelan has a message for the graduating class of 2012, and it is wonderful. He writes that he became sick of commencement speeches when he graduated. In the decades since his graduation,  he has studied happiness and well-being, and dishes out ten bits of wisdom to the graduating class. It’s a great read.

I completely agree with this advice:

Don’t make the world worse. I know that I’m supposed to tell you to aspire to great things. But I’m going to lower the bar here: Just don’t use your prodigious talents to mess things up. Too many smart people are doing that already. And if you really want to cause social mayhem, it helps to have an Ivy League degree. You are smart and motivated and creative. Everyone will tell you that you can change the world. They are right, but remember that “changing the world” also can include things like skirting financial regulations and selling unhealthy foods to increasingly obese children. I am not asking you to cure cancer. I am just asking you not to spread it.

This one sounds way easier to say than to carry out:

Marry someone smarter than you are. When I was getting a Ph.D., my wife Leah had a steady income. When she wanted to start a software company, I had a job with health benefits. (To clarify, having a “spouse with benefits” is different from having a “friend with benefits.”) You will do better in life if you have a second economic oar in the water. I also want to alert you to the fact that commencement is like shooting smart fish in a barrel. The Phi Beta Kappa members will have pink-and-blue ribbons on their gowns. The summa cum laude graduates have their names printed in the program. Seize the opportunity!