Biohacking post typos

_posts/2020-06-11-biohacking-lite.markdown

@@ -42,17 +42,17 @@ All four of these batteries are charged/discharged at all times to different amo
 <div class="imgcap">
 <img src="/assets/bio/energy_metabolism_1.png" style="width:45%">
 <img src="/assets/bio/atp_recycling.png" style="width:54%">
-<div class="thecap"><b>Left</b>: nice summary of food, the three major macronutrient forms of it, its respective storage systems (glycogen, muscle, fat), and the common "discharge" of these batteries all just to make ATP from ADP by attaching a 3rd phosphate group. <b>Right</b>: Re-emphasizing the "molecular spring": ATP is continuously re-cycled from ADP just by taking the spring and "loading" it over and over again. Images borrowed from <a href="https://voer.edu.vn/m/overview-of-metabolic-reactions/b446ba09">this nice papge</a>.</div>
+<div class="thecap"><b>Left</b>: nice summary of food, the three major macronutrient forms of it, its respective storage systems (glycogen, muscle, fat), and the common "discharge" of these batteries all just to make ATP from ADP by attaching a 3rd phosphate group. <b>Right</b>: Re-emphasizing the "molecular spring": ATP is continuously re-cycled from ADP just by taking the spring and "loading" it over and over again. Images borrowed from <a href="https://voer.edu.vn/m/overview-of-metabolic-reactions/b446ba09">this nice page</a>.</div>
 </div>
 
 
 Since I am a computer scientist it is hard to avoid a comparison of this "energy hierarchy" to the memory hierarchy of a typical computer system. Moving energy around (stored chemically in high energy C-H / C-C bonds of molecules) is expensive just like moving bits around a chip. (1) is your L1/L2 cache - it is local, immediate, but tiny. Anaerobic (2) via glycolysis in the cytosol is your RAM, and aerobic respiration (3) is your disk: high latency (the fatty acids are shuttled over all the way from adipose tissue through the bloodstream!) but high throughput and massive storage.
 
-**The source of weight loss**. So where does your body weight go exactly when you "lose it"? It's a simple question but it stumps most people, including my younger self. Your body weight is ultimately just the sum of the individual weights of the atoms that make you up - carbon, hydrogen, nitrogen, oxygen, etc. arranged into a zoo of complex, organic molecules. One day you could weigh 180lb and the next 178lb. Where did the 2lb of atoms go? It turns out that most of your day-to-day fluctuations are attributable to water retention, which can vary a lot with your levels of sodium, your current glycogen levels, various hormone/vitamin/mineral levels, etc. The contents of your stomach/intestine and stool/urine also add to this. But where does the fat, specifically, go when you "lose" it, or "burn" it? Those carbon/hydrogen atoms that make it up don't just evaporate out of existence. (If our body could evaporate them we'd expect E=mc^2 of energy, which would be cool). Anyway, it turns out that you breath out most of your weight. Your breath looks transparent but you inhale a bunch of oxygen and you exhale a bunch of carbon dioxide. The carbon in that carbon dioxide you just breathed out may have just seconds ago been part of a triglyceride molecule in your fat. It's highly amusing to think that every single time you breathe out (in a fasted state) you are literally breathing out your fat carbon by carbon. There is a good [TED talk](https://www.youtube.com/watch?v=vuIlsN32WaE) and even a whole [paper](https://www.bmj.com/content/349/bmj.g7257) with the full biochemistry/stoichiometry involved.
+**The source of weight loss**. So where does your body weight go exactly when you "lose it"? It's a simple question but it stumps most people, including my younger self. Your body weight is ultimately just the sum of the individual weights of the atoms that make you up - carbon, hydrogen, nitrogen, oxygen, etc. arranged into a zoo of complex, organic molecules. One day you could weigh 180lb and the next 178lb. Where did the 2lb of atoms go? It turns out that most of your day-to-day fluctuations are attributable to water retention, which can vary a lot with your levels of sodium, your current glycogen levels, various hormone/vitamin/mineral levels, etc. The contents of your stomach/intestine and stool/urine also add to this. But where does the fat, specifically, go when you "lose" it, or "burn" it? Those carbon/hydrogen atoms that make it up don't just evaporate out of existence. (If our body could evaporate them we'd expect E=mc^2 of energy, which would be cool). Anyway, it turns out that you breathe out most of your weight. Your breath looks transparent but you inhale a bunch of oxygen and you exhale a bunch of carbon dioxide. The carbon in that carbon dioxide you just breathed out may have just seconds ago been part of a triglyceride molecule in your fat. It's highly amusing to think that every single time you breathe out (in a fasted state) you are literally breathing out your fat carbon by carbon. There is a good [TED talk](https://www.youtube.com/watch?v=vuIlsN32WaE) and even a whole [paper](https://www.bmj.com/content/349/bmj.g7257) with the full biochemistry/stoichiometry involved.
 
 <div class="imgcap">
 <img src="/assets/bio/weight_loss.gif">
-<div class="thecap">Taken from the above paper. You breath out 84% of your fat loss.</div>
+<div class="thecap">Taken from the above paper. You breathe out 84% of your fat loss.</div>
 </div>
 
 **Combustion**. Let's now turn to the chemical process underlying weight loss. You know how you can take wood and light it on fire to "burn" it?  This chemical reaction is *combustion*; You're taking a bunch of organic matter with a lot of C-C and C-H bonds and, with a spark, providing the activation energy necessary for the surrounding voraciously electronegative oxygen to react with it, stripping away all of the carbons into carbon dioxide (CO2) and all of the hydrogens into water (H2O). This reaction releases a lot of heat in the process, thus sustaining the reaction until all energy-rich C-C and C-H bonds are depleted. These bonds are referred to as "energy-rich" because energetically carbon reeeallly wants to be carbon dioxide (CO2) and hydrogen reeeeally wants to be water (H2O), but this reaction is gated by an activation energy barrier, allowing large amounts of C-C/C-H rich macromolecules to exist in stable forms, in ambient conditions, and in the presence of oxygen.
@@ -67,19 +67,19 @@ Since I am a computer scientist it is hard to avoid a comparison of this "energy
 
 **Photosynthesis: "inverse combustion"**. If H2O and CO2 are oh so energetically favored, it's worth keeping in mind where all of this C-C, C-H rich fuel came from in the first place. Of course, it comes from plants - the OG nanomolecular factories. In the process of photosynthesis, plants strip hydrogen atoms away from oxygen in molecules of water with light, and via further processing snatch carbon dioxide (CO2) lego blocks from the atmosphere to build all kinds of organics. Amusingly, unlike fixing hydrogen from H2O and carbon from CO2, plants are unable to fix the plethora of nitrogen from the atmosphere (the triple bond in N2 is very strong) and rely on bacteria to synthesize more chemically active forms (Ammonia, NH3), which is why chemical fertilizers are so important for plant growth and why the Haber-Bosch basically averted the Malthusian catastrophe. Anyway, the point is that plants build all kinds of insanely complex organic molecules from these basic lego blocks (carbon dioxide, water) and all of it is fundamentally powered by light via the miracle of photosynthesis. The sunlight's energy is trapped in the C-C / C-H bonds of the manufactured organics, which we eat and oxidize back to CO2 / H2O (capturing ~40% of in the form of a 3rd phosphate group on ATP), and finally convert to blog posts like this one, and a bunch of heat. Also, going in I didn't quite appreciate just how much we know about all of the reactions involved, that we we can track individual atoms around all of them, and that any student can easily calculate answers to questions such as "How many ATP molecules are generated during the complete oxidation of one molecule of palmitic acid?" ([it's 106](https://www.youtube.com/watch?v=w6V9RFs9NGk), now you know).
 
-> We've now established in some detail that fat is your body's primary battery pack and we'd like to breath it out. Let's turn to the details of the accounting.
+> We've now established in some detail that fat is your body's primary battery pack and we'd like to breathe it out. Let's turn to the details of the accounting.
 
 **Energy input**. Humans turn out to have a very simple and surprisingly narrow energy metabolism. We don't partake in the miracle of photosynthesis like plants/cyanobacteria do. We don't oxidize inorganic compounds like hydrogen sulfide or nitrite or something like some of our bacteria/archaea cousins. Similar to everything else alive, we do not fuse or fission atomic nuclei (that would be awesome). No, the only way we input any and all energy into the system is through the breakdown of food. "Food" is actually a fairly narrow subset of organic molecules that we can digest and metabolize for energy. It includes classes of molecules that come in 3 major groups ("macros"): proteins, fats, carbohydrates and a few other special case molecules like alcohol. There are plenty of molecules we can't metabolize for energy and don't count as food, such as cellulose (fiber; actually also a carbohydrate, a major component of plants, although some of it is digestible by some animals like cattle; also your microbiome loooves it), or hydrocarbons (which can only be "metabolized" by our internal combustion engines). In any case, this makes for exceedingly simple accounting: the energy input to your body is upper bounded by the number of food calories that you eat. The food industry attempts to guesstimate these by adding up the macros in each food, and you can find these estimates on the nutrition labels. In particular, naive calorimetry would over-estimate food calories because as mentioned not everything combustible is digestible.
 
-**Energy output**. You might think that most of your energy output would come from movement, but in fact 1) your body is exceedingly efficient when it comes to movement, and 2) it is energetically unintuitively expensive to just exist. To keep you alive your body has to maintain homeostasis, manage thermo-regulation, respiration, heartbeat, brain/nerve function, blood circulation, protein synthesis, active transport, etc etc. Collectively, this portion of energy expenditure is called the Base Metabolic Rate (BMR) and you burn this "for free" even if you slept the entire day. As an example, my BMR is somewhere around 1800kcal/day (a common estimate due to Mifflin St. Jeor for men is *10 x weight (kg) + 6.25 x height (cm) - 5 x age (y) + 5*). Anyone who's been at the gym and ran on a treadmill will know just how much of a free win this is. I start panting and sweating uncomfortably just after a small few hundred kcal of running. So yes, movement burns calories, but the 30min elliptical session you do in the gym is a drop in the bucket compared to your base metabolic rate. Of course if you're doing the eliptical for cardio-vascular health - great! But if you're doing it thinking that this is necessary or a major contributor to losing weight, you'd be wrong.
+**Energy output**. You might think that most of your energy output would come from movement, but in fact 1) your body is exceedingly efficient when it comes to movement, and 2) it is energetically unintuitively expensive to just exist. To keep you alive your body has to maintain homeostasis, manage thermo-regulation, respiration, heartbeat, brain/nerve function, blood circulation, protein synthesis, active transport, etc etc. Collectively, this portion of energy expenditure is called the Base Metabolic Rate (BMR) and you burn this "for free" even if you slept the entire day. As an example, my BMR is somewhere around 1800kcal/day (a common estimate due to Mifflin St. Jeor for men is *10 x weight (kg) + 6.25 x height (cm) - 5 x age (y) + 5*). Anyone who's been at the gym and ran on a treadmill will know just how much of a free win this is. I start panting and sweating uncomfortably just after a small few hundred kcal of running. So yes, movement burns calories, but the 30min elliptical session you do in the gym is a drop in the bucket compared to your base metabolic rate. Of course if you're doing the elliptical for cardio-vascular health - great! But if you're doing it thinking that this is necessary or a major contributor to losing weight, you'd be wrong.
 
 <div class="imgcap">
 <img src="/assets/bio/cookie.jpg" style="width:39%">
 <img src="/assets/bio/sweating.jpg" style="width:60%">
 <div class="thecap">This chocolate chip cookie powers 30 minutes of running at 6mph (a pretty average running pace).</div>
 </div>
 
-**Energy deficit**. In summary, the amount of energy you expend (BMR + movement) subtract the amount you take in (via food alone) is your energy deficit. This means you will discharge your battery more than you charge it, and breath out more fat than you synthesize/store, decreasing the size of your battery pack, and recording less on the scale because all those carbon atoms that made up your triglyceride chains in the morning are now diffused around the atmosphere.
+**Energy deficit**. In summary, the amount of energy you expend (BMR + movement) subtract the amount you take in (via food alone) is your energy deficit. This means you will discharge your battery more than you charge it, and breathe out more fat than you synthesize/store, decreasing the size of your battery pack, and recording less on the scale because all those carbon atoms that made up your triglyceride chains in the morning are now diffused around the atmosphere.
 
 > So... a few textbooks later we see that to lose weight one should eat less and move more.
 
@@ -134,4 +134,4 @@ Clearly, my actual weight loss (red) turned out to be slower than expected one b
 <div class="thecap">The raw numbers for my DEXA scans. I was allegedly losing fat. The lean tissue estimate is noisy due to hydration levels.</div>
 </div>
 
-**Summary** So there you have it. DEXA scans are severely affected by hydration (which is hard to control) and BIA is making stuff up entirely, so we don't get to fully resolve the mystery of the slower-than-expected weight loss. But overall, maintaining an average deficit of 500kcal per day did lead to about 60% of the expected weight loss over the course of a year. More importantly, we studied the process by which our Sun's free energy powers blog posts via a transformation of nuclear binding energy to electromagnetic radiation to heat. The photons power the fixing of carbon in CO2 and hydrogen in H2O into C-C/C-H rich organic molecules in plants, which we digest and break back down via a "slow" stepwise combustion in our cell's cytosols and mitochondria, which "charges" some (ATP) molecular springs, which provide the "umph" that fires the neurons and moves the fingers. Also, any excess energy is stockpiled by the body as fat, so we need to intake less of it or "waste" some of it away on movement to discharge our primary battery and breath out our weight. It's been super fun to self-study these topics (which I skipped in high school), and I hope this post was an interesting intro to some of it. Okay great. I'll now go eat some cookies, because yolo.
+**Summary** So there you have it. DEXA scans are severely affected by hydration (which is hard to control) and BIA is making stuff up entirely, so we don't get to fully resolve the mystery of the slower-than-expected weight loss. But overall, maintaining an average deficit of 500kcal per day did lead to about 60% of the expected weight loss over the course of a year. More importantly, we studied the process by which our Sun's free energy powers blog posts via a transformation of nuclear binding energy to electromagnetic radiation to heat. The photons power the fixing of carbon in CO2 and hydrogen in H2O into C-C/C-H rich organic molecules in plants, which we digest and break back down via a "slow" stepwise combustion in our cell's cytosols and mitochondria, which "charges" some (ATP) molecular springs, which provide the "umph" that fires the neurons and moves the fingers. Also, any excess energy is stockpiled by the body as fat, so we need to intake less of it or "waste" some of it away on movement to discharge our primary battery and breathe out our weight. It's been super fun to self-study these topics (which I skipped in high school), and I hope this post was an interesting intro to some of it. Okay great. I'll now go eat some cookies, because yolo.