You're probably hot if you have a fast metabolism - rudimentary thoughts on "fast" and "slow" metabolism.

- Gautham

(An update of something I posted on facebook many years ago on applying some simple thoughts related to machine efficiency to the topic of human weight loss and gain and "slow/fast" metabolism).

I sometimes run into people (usually young males) who want to gain weight but claim they can't because they feel they have a fast metabolism. The first question I ask is what did they have for breakfast. The answer was nothing or not much, which is typical. Literally >80% of people that I've run into that say they can't gain because of metabolism don't eat a substantial breakfast. It is extremely hard to make it over the bar with two meals a day rather than with three or four. I have grown very suspicious of this talk of "metabolism" differences. They may be there but my guess is that they are overstated.

 

What would it mean for someone to have a fast metabolism?

 

If your body composition and weight is at steady state, the following must be true, because a fuel that is not stored must be either burned, used for work (which also produces some heat), or thrown out (can you think of another option?):

 

Food in = Food out (excreted) + Work done + Heat produced.

 

In this scheme, the only way you can eat more than someone of identical mass but remain at steady weight is if: 

1. You excrete more.
2. You do more work. Maybe you run more than someone, or you run the same but inefficiently. Maybe you are a fidgeter as opposed to a laid-back relaxed type. This could include having a more muscular composition, which is said to require greater work to maintain.
3. You expel more heat. This could be some combination of the following factors:

• You have a harder time keeping your body temperature because of higher surface area, less clothing, or colder ambient temperature.
• You have a substantially higher body temperature. 

Considering that heat loss is proportional to the temperature difference between you and your surroundings, a 10% faster metabolism that doesn't involve more excretion, more work or higher surface area means that your temperature difference with the environment is at least 10% larger. For a normal human being at room temperature (25C), this would mean your body temperature is at least a full degree celsius warmer: from 37C to 38C. And that is just for a 10% faster metabolism.

So if you want to claim that you have a fast metabolism, an implication is that you are likely running hot. The other option is a high heat transfer coefficient.

More likely, a close examination of total food intake and activity will show that systemic differences are smaller than they seem.

Metabolism slowing down when you get older 

Looking at things this way, it reduces the plausibility that anybody's metabolism 'slows' down when they grow older. That used to make sense - oh it slows down, like cars or other devices with age. 

However, this way of thinking implies that the design goal of human physiology is to be able to eat more without increasing in weight. Our long-ago ancestors would strongly disagree that this was the main problem they were facing.

 

A 'slowdown' in metabolism in the sense people usually seem to mean (I am doing everything the same as when I was younger but I am gaining weight) actually would imply an increase in work efficiency of the body. You work more efficiently or you expel less heat. In this sense, a person's metabolism slowing down with age is like a car's gas mileage increasing the longer you have it.

More likely, as a friend pointed out, an older person with a "slower" metabolism is simply doing less physical work (perhaps due to learning how to do things more efficiently), not exercising, not fidgeting, living in comfortable climate-controlled surroundings, etc. 

So in both cases: decline with age and apparent variation between people, perhaps best to first carefully look at what one eats and what one does before concluding that the difference is in one's own system.

Let others organize your e-mail

One of the biggest management issues people have with e-mail is that so much different stuff comes through your e-mail box that it’s hard to keep track of. For instance, research e-mail, teaching e-mail and committee e-mail all come into the same inbox, waiting for me to sort it all out. I could sort it all into mailboxes/labels, but honestly, it’s too much work, so I rely on search. But search is only so good–it’s not perfect, and sometimes there are times when I need to find *all* responses to a particular e-mail from a variety of people, and it’s not okay to miss one of them. It’s tricky because sometimes the respondents will change the subject line or not include the original message in their reply, which means stuff can slip through the search engine. What to do?

Recently, it occurred to me: why not let people who e-mail me do the sorting? There are a couple ways of doing this, and I’ve implemented one and am considering implementing the other:

1. Just make a new e-mail address. This term, I made myself a specific e-mail address just for teaching. I instructed my students to just use this e-mail address for contacting me. This serves two purposes: first, it makes it much easier to sort for these messages so that I can find *all* teaching associated e-mails without having to do any filing or searching. Second, it makes me much less likely to miss some teaching-related e-mail tangled in their with the rest of my e-mail, making me more responsive. So far, so good–I think it’s a clear win here. But I don’t think this strategy can work except for cases where you have a very clear delineation of communication. Some people have a “important” e-mail vs. a “everyone else” e-mail. But any time there’s a blurry line, there will be bleed through, and over time it just devolves into a mess. For teaching, though, this works well.
2. Use the yourname+string@gmail.com trick. I just learned recently about a cool Gmail feature, which is that if your Gmail address is yourname@gmail.com, then if “string" is any string, yourname+string@gmail.com will also come to your Gmail inbox, but the “To” field will be yourname+string@gmail.com. Basically, this allows senders to add tags to the e-mails they are sending you! The problem, of course, is that they have to know about your tags ahead of time, and actually be conscientious enough to stick to it (which of course I wouldn’t do). But there is a way to encourage this: use the “Reply To” field. Let’s say I’m asking for faculty feedback on some departmental matter. Then I can send out the e-mail with arjunrajgmail+facultyfeedback@gmail.com in Reply To and hopefully all the responses will be all nicely tagged. I haven’t tried this yet, but let me tell you, I really wish I had thought of this about 2 months ago…

Anybody else have other tricks for how to manage e-mail?

Being the best

I was just playing the game "Threes" (very addictive, highly recommended) with my son, and I was thinking, "Huh, this is a fun game, I wonder what's the highest number you can get?" Then I thought, oh jeez, there's got to be some kid in Estonia who has gotten some simply astronomical score–better not to even check. It's a unique time in history, I think, when we can so easily see the best in the world at just about everything. Is this good or bad? I can see it pushing people to get better, to be the best. I can see it making people give up entirely, thinking about how hopeless it would ever be to get so good at something (I find myself in this camp with most video games these days). Maybe some people even respond in the way we always imagine we would, namely ignoring the world at large and focusing rather on how to make ourselves better, which is the truest form of the journey we are on.

At the same time, our society has also evolved to make everyone feel like a "winner" all the time. Sometimes there are so many awards for stuff for kids that you would feel bad if your kid didn't win anything. Then we end up with these kids in college who can't believe that they got a B+ for getting the class average.  It's a strange dichotomy, I feel...

Protocol repository Kickstarter

So my friend Lenny Teytelman has a kickstarter campaign going for a project to make an open protocol repository. A great cause to support!

How to maintain "clean experiments"?

During his presentation on software design and "clean code", Gautham made an excellent point: if we spent half as much effort making our code clear as we did on making our papers clear, our code would be pristine. And it's true: I know that I'm fairly relentless about making figures well and trying to write as clearly as possible. It's an exhausting, iterative process, but I feel like it's really important, and I think it's a good idea to apply the same sensibility to our code, which thankfully Gautham has done.

That got me thinking about what other aspects of our work could benefit from a focus on clarity and cleanliness, leading me to a natural candidate: our data. Currently, I am a stickler for "data trails". Every single figure in every paper lives completely in a folder in which lives a single script which, when run, will generate all the elements of the figure from raw data without any manual input required. This way, when you are wondering exactly where that one funny data point came from, you can (relatively) easily find that one threshold from that one cell from that one experiment that led to that data point. Some of this relies on software design, making sure that the code we use the analyze data keeps track of all the relevant metadata.

But what I haven't focused on or really thought about very much is how best to systematize data at the experiment level. That is, how can we ensure that we log our data appropriately and make sure that we can find what we need when we need it. Yes, of course we use lab notebooks and Google Docs, but it's currently a bit of a mish-mash. What is the best way to do this? I don't know, but here are a few of the important features I think such a system must have:

1. It must have low overhead. If you have to take off your gloves in the heat of an experiment to go make an entry in your Google Doc log, there's a high probability it's not going to happen. Paper notebooks are great at this, computers bad, tablets good. I initially bought netbooks for the lab for this purpose, but nobody used them because they were so crappy and took like 38 minutes just to wake from sleep. Maybe an iPad?
2. It must be searchable. This is the singular failure of the paper notebook, which is otherwise so wonderful in so many ways. If you can search quickly through your old experiments to see which experiments used so and so reagent, it really makes you more productive. This is killer, and Google Docs rules for this. Even on a tablet, though, I don't know how you can combine handwriting with searchability, unless you have good optical character recognition.
3. It must be flexible. It has to somehow be able to quickly capture a large number of different types of experiments. Most electronic lab notebooks are so structured and unwieldy, with so many things to click to define your experiment, that they're just not worth the hassle. Again, freeform, like the paper notebook, makes the most sense here.

So far, the closest thing looks like some sort of tablet app that can translate handwriting to searchable text with a cloud organization option would make the most sense. Anybody know of such a thing?

Changing your mind in math

I just posted about changing your mind, and I remarked that math is immune to this because someone is right. True, in a formal sense. But then I (vaguely) remember the following evolution of responses to something new in math:

1. Your result is wrong.
2. Your result is right, but it is trivial.
3. Your result is implicitly known to everyone in the field.
4. Your result has been well known for many decades.
5. Profs. XYZ had that idea many years ago.
6. I had that idea many years ago.
7. You might be on to something.

Along these lines, a reviewer of one of our papers clearly didn’t like it, but we wore them down, and they eventually relented, saying something like “Let history be the judge”. History has actually treated the paper well, but I thought that was pretty funny!

PS: I could have had this series of responses wrong–I don’t remember how it went exactly. Let me know if I got it wrong.

Changing your mind

Scientists argue with each other. A lot. This is supposed to be a good thing, and I think that in its best form, criticism is one of the best ways to ensure the soundness of an approach or the veracity of a discovery. But I think there is an important nuance here: criticism is only useful if someone is willing to change their mind. Ideally both parties, but at least one of them. If you are unwilling to be persuaded by facts, or even entertain plausible alternatives to your point of view, then you are no different from those talking heads on political talk shows. Scientists are not immune to this, as we are humans and as such have our own mental inertia of what we feel is right and wrong (part of the beauty of math, I suppose, is that there is an ultimate arbiter in the dispute). I certainly have had some notions that I’ve been wedding to long past their expiration date.

As such, I’ve been wondering how to do a better job of being open minded. Which got me thinking a bit more about how the process of changing one’s mind actually happens. I find that I rarely change my mind during the actual discussion. Perhaps this stems from the natural desire to defend one’s own position, which I suppose requires what is on some level a fundamentally irrational belief in said position. Usually, I change my mind after the fact, when I have time to think more carefully about all the different points someone made. Is it possible to change this dynamic to make it faster? Or is this just inherent to the process? I feel like my discussions could sometimes be more productive if I could make it easier for me to readily accept new ideas and thoughts counter to my own preconceptions. Hmm. It is as simple as just being more open minded in more situations? I don't think I'm a particularly closed-minded person, but I could be better, I think...

Interesting related side note about review processes: did you know that at the patent office, you can request an interview with your patent examiner to discuss the case face to face (or voice to voice)? Wouldn’t it be nice to have an actual discussion with paper/grant reviewers? I feel like that would make everything much much better.