Continuous Glucose Monitoring

If you are diabetic or heard enough about Continuous Glucose Monitoring from the media/friends already, you can skip this post completely. 

Last time I went for a routine medical checkup/blood work, the numbers showed me as one who has just reached pre-diabetic stage. If you are not familiar with this diagnosis, it is nothing too alarming, as millions of people all over the world live in this state for decades. The medical industry's guidance at this stage is to "just watch", meaning no medication or change in lifestyle required. They will keep testing once a year to see if we actually become diabetic, after which medications will be prescribed. To me, this doesn't make sense, since this is the time to dig into the data to see what changes we can make in our diet and exercise routine so that the A1C numbers don't continue to trend up. Though things like reducing weight, exercising more and eating less carbs will all help, since each individual's metabolism is different, getting lot more data about our particular body/food/exercise habits to see what we can easily to tweak to go back to normal state is what made sense to me. 

To gather a lot of data, bought a Freestyle Libre CGM (Continuous Glucose Monitoring) system, that has a sensor that you attach to your body and a reader, using which you can read your blood glucose level in a second, whenever and as many times as you want. Till two weeks back, getting a CGM in the US usually required a doctor's prescription, whereas in other parts of the world, you can purchase one OTC (Over The Counter). The US FDA changed the rule couple of weeks back allowing OTC sales in US as well. Hopefully it will bring the price down. While there are a lot of models, types, version, the one I bought costs roughly $100 for the reader and $30 for the sensor that works for two weeks (exactly, to the minute). I got a second sensor, in case I mess up while putting on the first one. But it was easy to put on and so I have a spare one now, that someone else can use later. 

You can find a lot of details about CGM online, and in YouTube videos. But here are a few photos/video explaining what I did.

https://photos.app.goo.gl/2q2qfHiXDTfPAoLV7 

The Abbott Labs that sells this particular model wants you to create an account, and upload all the data to their cloud, so that they can analyze and give your results/recommendations. Since the EULA wants you to allow them to own/use the data however they want, forever, I felt uncomfortable and went through the painful process of entering all the data into a spreadsheet and doing the analysis myself. If you don't mind giving away your data, you can download apps available online, and use the provided USB cable to easily transfer the data to get the analysis done online. 

This reader also has the interface to take glucose blood test strips to provide you the reading, though I didn't use it myself. There are newer versions of the device, where using the Bluetooth interface, data can be directly transferred to your phone and then on to the cloud, etc. I intentionally used a low-tech version where the reading stays in the handheld reader, that is about the size of pager, with a very easy to use, single button interface.

The sensor actually measures the glucose levels in the Interstitial Fluid rather than in the blood hemoglobin but is considered pretty accurate, since the reader can use a formula to covert (i.e. estimate) it to blood glucose level. 

I took about 20 to 25 readings each day for the past two weeks and so have about 300 readings. The sensor you attach to your body does gather the glucose data continuously and so even if you don't read it so many times, when you do, it will transfer all the data to your reader. You can see it in the graphs the reader plots & shows you (see photos). But since the reader screen size is small, and since I wasn't transferring the data to the cloud, I am depending more on the 300 manual readings I took and recorded on a spreadsheet with notes on foot/activities. (See update 1 below.)

Observations made are applicable mainly to me, since the reason to go through this process is to get a better understanding of our own specific (i.e. one person) metabolism. Still, I am listing a few salient points I gathered, since these insights may be useful for others to follow or may indicate the value & surprise findings you derive by going through this exercise. I defined my "normal range" of glucose reading as 70 to 120 mg/dL.

- Eating a cup of plain white Raman noodles (without adding any vegetables, proteins, flavors, etc.) causes a glucose spike close to 200. I used this as a baseline to test couple of theories.

- Eating the same plain noodles, preceded by a small salad, flattens the spike, limiting it to about 150. 

- Eating the same plain noodles, followed by 20-25 minutes of moderate exercise (like brisk walking), flattens the spike, limiting it to about 150. 

- White rice eaten with Sambar/rasam/butter milk (typical south Indian lunch/dinner) causes a spike close to 200.

- Preceding the identical meal with a small salad keeps it under 150. 

- Alternately replacing white rice with cooked bulgur wheat or brown rice eliminated the spike.

- Eating a small salad or protein, seems to coat/occupy your intestine preventing any subsequent carb/sugar from being quickly absorbed that seems to cause a spike. 

- Eating 1.5 slices of toasted whole wheat bread OR just one cup of south Indian rava uppuma caused a sharp spike. I think white bread would have caused even a bigger spike. 

- I tried all types of food (Mexican, Italian pasta, pizza, black coffee, coffee with milk & sugar, fruit smoothie, pistachio nuts), different type of exercise (walk, jog, weights, stretches/sit-ups) and took readings to see how/what I can optimize to prevent spikes.

There are articles like this one that argues why common public should NOT do CGM, and how spikes after eating different food is quite normal, as long as the glucose level comes down on its own in the following hour. I do understand those points and my levels do come down. Still, being an engineer, I prefer & tend to measure, analyze, debug and fix issues before they become a crisis. I am hoping to use the collected data to modify my diet & exercise routines to see if I can go back to being normal (instead of pre-diabetic) next time I go for a checkup. If I can do that, I'd have gotten my money's worth, and this process will be in line with my goal of living a healthy life as long as I can without resorting to chronic daily medication just to lead a normal life. Will tell you how it goes after 6 months or 1 year. 

If you are already an expert and have pointes for me, drop me a note.  

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Update 1: Weeks after writing this post, I did manage to upload all the data to Abbott without giving my personal details to remain anonymous. It showed about 1700 data points gathered by the reader, instead of the mere 300 I had. It also did a really nice analysis and gave me a 16-page PDF that is much more comprehensive than mine.)

Update 2: It's been 7 months since I started making tweaks to my diet & exercise routines. Dropped few pounds, did more exercise, ate salad (with Apple Cider Vinegar) regularly before most meals, replaced white rice with brown rice, etc. So, wanted to see if all this had the right impact. When I asked my PCP (Primary Care Physician) for an A1C test, I was told that US health insurance will allow only one A1C test per year (as part of annual blood work) since I am not diabetic and so I can have one only in the next calendar year. I didn't want to wait till January 2025 and so bought a home A1C test kit and did the test myself. It showed my new Hemoglobin A1C percentage number is 5.4. This is better than my 2016 number of 5.5! Since then, it has always monotonically increased. Though home test may have accuracy issues, since this number is even better than my 8-year-old reading, I think I can safely conclude that the last 8-months of tweaks are working. I don't need to lose any more weight but will stick to ongoing diet & exercise routines. Hopefully I can confirm the numbers next year when I get the annual blood work done. 

For engineers, there is no better buzz than seeing a specific fix you put in addressing a bug in the system. 

If you are interested in this topic, consider listening to this one podcast episode about Novo Nordisk:

https://www.acquired.fm/episodes/novo-nordisk-ozempic

Book Review: Chip War by Chris Miller

This book titled Chip War - The fight for the world's most critical technology by Chris Miller came out in late 2022 and became a best seller quickly garnering a lot attention. Since I keep yapping about semiconductors all the time, many friends, including my own team members who have read the book kept asking me if I had read it. Since I am slow reader, who still haven't learned to skim through a book perfunctorily, I remained reluctant to pick it up. I thought it may not have a lot of new material for me to learn, as we have been living this history for the past few decades. But the noise about the book was getting deafening, with our own CEO interviewing the author, and various news media outlets incessantly talking about it. So, decided to pick it up from the local library. While I should honestly say there wasn't a ton of new information for the semiconductor industry oldies like myself, I thoroughly enjoyed the read. It felt similar to watching a good movie you liked for the second time! If you are not in the semiconductor industry, I will highly recommend this book as the material is written in an extremely accessible prose covering lucidly not only the old history but the current status and how critical this technology is for the entire world.

Author is not an industry expert but an academic, who teaches international history. Since he has taken the time and put in the effort to grok a lot of material, conducted a ton of firsthand interviews, the story arc has come out very well, bearing his international history background as the overarching signature. Most of the individual chapters are only 4, 5 pages long, while the total book spans a respectable 350 pages. Starting from cold war days, the invention of integrated circuits, book chronicles how this technology originally invented in the US, was taken over by countries like Japan in the 80's forcing companies to reinvent themselves. There are several stories and personalities from Intel since it is a quintessential part of the world's chip industry history. While in the late 80's it looked like US has totally lost the leadership, US companies managed to out invent everyone else, bringing the leadership back to the US for couple of decades. But the subsequent developments, such as the emergence of TSMC that prints chips for most of the world, has reshaped the world and this market. Countries like Russia and China see the importance of being a leader in this domain from both military and civilian national requirements but haven't succeeded in becoming serious players so far, despite a lot of government push, deluge of subsidies and even industrial espionage. While most people in the world think of chips as some commodity similar to potato chips (i.e. fungible, gets produced somewhere and used somewhere, without the locations mattering much), the pandemic that resulted in chip shortage that brought things like automobile production lines to a halt, helped the world realize how smoothly this supply chain has been running in the background.

Though US controls many choke points such as high-end chip design software, currently the manufacturing prowess to produce the most advanced chips sit with TSMC and Samsung. Our company Intel Corp is trying to catch up, working with companies like ASML that manufacture the machines needed to make these cutting-edge chips. Building each generation machines and factories costing literally tens of billions of dollars involving extreme specialization makes this cutthroat competitive world a difficult one to survive. Just take a look at this one short video our company has put out to see how complex the technology is. If you pay attention to the process of generating the UV light that doesn't exist naturally, you will see why the effort we need to go through and the technology that need to work flawlessly to print the next gen microchips is truly mind boggling. If you don't ask. "Are you kidding me? Is this for real?", you weren't paying attention. 

While I am tempted to write a lot more, I am trying to keep this short and will highly encourage those who are not working in the field of semiconductors to reach this book to understand the breadth and importance of this field. Same recommendation for new young engineers in this field as well! 

Time to go back to The Song of the Cell by Siddhartha Mukherjee that I am only halfway through! 

Book Review: Outlive by Peter Attia

This book titled "Outlive - The Science and Art of Longevity" came out just last year (2023) and seems to be making waves. My friend Sanjay Padubidri recommended it and so picked up a copy from our local public library. Since it is a fairly new book, it came on a two week loan, instead of the usual 3 week period. Though at 410 pages, it looked like a big book, it was an easy read and yes, it could have been shorter in length, like this book review. 

Attia is a practicing physician and has written this book with Bill Gifford, though pretty much every line is written in first person singular mode. Classifying and giving names to everything is a common practice in the US these days. In that tradition, he starts off discussing medicine as Version 1.0 (medieval practices like blood letting, etc.), 2.0 (current version that focuses on issues after they show up) and 3.0 (where a lot of treatment is preventative). Then spends a lot of pages talking about the "the four horsemen" of ailments that pain us as we age, viz. metabolic issues like diabetes, heart health issues, cancer and neurological issues like Alzheimer's. Second half of the book dives into measuring everything possible, finetuning our routines (in eating, exercising, sleeping) to prevent or delay these ailments from slowing us down, so that we can "Outlive" them into a happy, healthy old age. 

Books gets into the details of each area (e.g. functions of various genes, enzymes, hormones) and also adds a lot of personal stories about patients he treated, how he was so ignorant and over the decades learned his lessons and so on. While these makes it all very easy to read as there is not a lot of difficult concepts that you need to remember, it also feels like very many pages could have been eliminated, including sections meant for his humble bragging. On the positive side, certainly liked the fact that he is not pushing any one wonder drug or diet or practice that will solve everything but is evangelizing a comprehensive approach of moderation on multiple fronts (diet, sleeping, exercising, taking needed medication). The overall takeaways are presented in an easy to remember fashion and so it is worth a read, though it may not be necessary to buy and keep a copy. Last round of annual check up I had showed me as mildly pre-diabetic. Based on what Sanjay was telling and this book is suggesting, thinking of getting a CGM (Continuous Glucose Monitor) for a month or two to get a lot of data. This should help me tweak whatever I can in diet/exercise to continue my general goal of living a healthy happy life as long as I can, without having to take chronic medication. Will see how it goes. Looks like many such "lifestyle gurus", he is also making an industry out of this with a website where he is posting videos, podcast, book, patient sessions, etc. Though there is nothing wrong with any of that, it reminded me of another writer mildly making fun of an Indian Swamiji pushing spiritualism, who has established an equivalent of a mega church that takes Mastercard and Visa for their services!