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I Tracked My Diet And Weight For 6 Months And Lost 15 Pounds

Jerry Zhang
Jerry Zhang

9 min read

The data in this article reflects the year of 2020 between the months of January and June.

I’ve never considered myself to be physically fit. As a child, I was fairly chubby. As a college student, I was overweight. Even after college, I remained overweight.

For some reason, I just assumed that my body would take care of itself.

But that’s not true. While your body will do its best, it can only play with the cards that it has been dealt with. And if you keep feeding it endless amounts of sugar without getting any exercise, your body stands no chance.

This article is meant as a practical guide to tracking your own health data so you can keep yourself accountable and draw insights on your own behaviors. I will include samples of my own data and charts and explain each step along the way.

At the end of this article, I'll provide a link to a sample spreadsheet that you can use to get started.

A Wake-Up Call

According to the National Institute of Health, 70% of adults in the US are either overweight or obese. And here’s a non-exhaustive list of the risks associated with being overweight or obese:

  • Type 2 diabetes
  • High blood pressure
  • Heart disease
  • Stroke
  • Cancer
  • Kidney disease

Wow. That’s jarring. And that’s not even all the risks.

Since I was overweight, I was subjecting my body to those risks. Through my own choices and actions, this is a fate I’ve subjected my own body to.

And the worst part — it’s all something I can control.

How could I have ignored my health for the past 20+ years in my life? My body should be filing thousands of lawsuits against me for my gross negligence.

My Personal Health Experiment

As an engineer, I learned to trust data. If the National Institute of Health can gather data to measure the entire American population, surely I can gather data on just one person — myself.

So I started this personal experiment for myself. Note that I’m not a fitness expert offering health advice — I am simply a regular guy who wants to become more healthy.

As you read in the title, I’ve lost 15 pounds in 6 months so far. And I don’t plan on stopping my experiment any time soon. Here’s what I did.

I Kept A Food Journal

I started by writing down everything I ate into a spreadsheet (I use Google Sheets, but Excel will work as well). I would date and categorize each food based on the type of meal (breakfast, lunch, dinner, snack, drink).

Some days I’ll eat pretty healthy:

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And other days I’ll have had too much:

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This is extremely helpful because it caused me to become aware of what I was eating each day. And I can easily look back and see what I’ve been eating.

I Counted Calories

To enhance my food journal, I counted calories for each entry as well. Here’s the same example above with calorie counts:

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Some entries that provide exact nutritional values are easier to estimate. For example, food and drink merchants like In-N-Out and Pressed provide the exact numbers.

Other entries are more difficult to count in the absence of those exact values. For example, quantifying entries like chips in which I only eat parts of the whole bag. In this case, the number exists for the whole bag and it tells me how many total servings are in the entire bag and the count for each serving.

In general, many entries require me to estimate since there are no exact nutritional metrics. This meant googling “how many calories in …” over and over again on absolutely everything I eat.

Confession: I’ll just eyeball it. Yes, it’s not super precise. But I would rather have some data than no data at all. And my rule is that I must provide at least an overestimate. I would prefer to under-eat than overeat. That way, I guarantee I won’t “accidentally” gain weight because of undercounting.

I’m still not perfect at estimating calories yet, but I am getting better with practice.

Note: I’m not as intense as using food scales to weigh my food down to the gram. That’s too much work and I don’t plan on doing that any time soon. But having a conservative over-estimate is better than having no data at all.

I Tracked Exercise

Much later into the experiment, I also started tracking my exercise as well as my daily base metabolic rate (BMR). Here’s an example:

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Base metabolic rate is the amount of energy we burn by doing absolutely nothing. Our body needs some energy just to stay alive. I just googled this number for myself, which is based on weight and sex.

Then, I’ll count any cardio-related exercise, such as running.

Notice how the values for BMR and Exercise are reported as negative. This reflects the calories burned.

I’ve been consistently exercising for 2–3 months now. I am still figuring out the best way to measure exercise and will report back if I have any updates.

I Created A Pivot Table

And now, it’s time to sum my health tracking data all into a daily report. Spreadsheets have a cool feature called a pivot table that allows me to do this quite easily. (Teaching pivot tables is beyond the scope of this article. There are plenty of good guides online.)

Here’s how I constructed my pivot table:

  • Rows: Category, Sub-Category
  • Columns: Date
  • Values: SUM of Calories

Here’s an example of my recent daily calorie count and its breakdown:

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As you can see, this allows me to easily see my daily calorie count by BMR, Exercise, and Food. I can further see a breakdown of Exercise (only running for now) and Food (by meal type).

And at the bottom, I can see whether I am positive, neutral, or negative each day. My daily goal is to be neutral or negative.

I Weighed Myself Daily

As part of my morning ritual, I weigh myself right after I get up. I use a digital scale that connects to my phone via Bluetooth. It’s actually really cool since it shows me other metrics, such as muscle mass (and a bunch of other metrics that I have not figured out yet). See for yourself below:

Here’s a plot of my weight over the last 6 months:

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When I first started weighing myself, I couldn’t see any progress. It takes at least 2 weeks before you start seeing some trend.

Looking back over the last 6 months, I can see a clear trend of my efforts.

My Spreadsheet

Here's a link to my spreadsheet. It's read-only, so if you want to edit, you'll need to copy it to your own account.

I truncated the data to include just my June's food journal. With this spreadsheet, you should be able to create your own charts like the ones I've showed you in this article.

If you decide to also take this data-driven approach to measuring your health, I look forward to hearing about your results! I'll leave you with a few tips for you to get started.

Some Basic Advice

I recognize that there are several things about health and fitness that I still do not know. I wanted to write about my personal health experiment so far just to show you that this is possible for anyone, even if you’re not a fitness expert.

Finally, I wanted to leave you with some advice that helped get me where I currently am.

1. Acknowledge That Change Is Necessary

For me, it was the wake-up call that physical fitness is important to life longevity and overall healthiness. I was causing my own body harm, and that needed to stop.

If God permits me to live long enough, I want to be around to see grandchildren and maybe even great-grandchildren.

2. Keep it Simple

I’m not a health nut, and I did this. It doesn’t have to be some crazy restrictive diet or insanely difficult workout. It can be simple.

I didn’t have to drastically change my life. I still allowed myself to eat whatever I wanted, as long as I recorded it down and tracked its calorie count, and as long as I was willing to face the scale the next morning.

I don’t believe in any dieting fads or some insane workout regiments. Honestly, those are either too good to be true or require so much work that you’ll quit before you reach the promised goal. And if you start one of those and don’t end up finishing, you’re likely to lose further motivation.

3. Record Your Data Immediately

To prevent yourself from forgetting, I highly recommend recording your data immediately. For example, if you just had your meal, write down what you ate and the calorie count right away.

If you don't have access to your spreadsheet, make a note on your phone so you can record it later. If you don't know how many calories your meal consisted of, at least write down what you ate so you can look it up later.

Recording your data immediately also has the second helpful benefit of tracking your progress along with your day to see how much budget you have left for the rest of the day. If you're going to a family Thanksgiving dinner and planning to splurge, you might want to save up throughout the day or even get some exercise in to give yourself more leeway later.

4. Be Consistent

Now that you know what you need to do, continue to do it without ceasing.

This is where habit and routine come into the picture. Unless you can perform boring repetition over and over again, you won’t get anywhere in the long run. That’s why it’s important to keep it simple and as mindless as possible.

I am a big fan of evening and morning rituals. I’ve written about both of mine below:

This Morning Ritual Guarantees A Great Start To Any Day
We live in a fast-paced world where it may feel difficult to distinguish this day from the next. A morning ritual helps ground you to face any day!
This Evening Ritual Ends My Day With Full Closure
We live in a fast-paced world where it may feel difficult to distinguish this day from the next. An evening ritual helps you slow down and regain control.

The goal is the longer you do this, the less thinking you need to do and it will just become automatic. Turning it into an instinct in which you don't need to reason with yourself on why is the ultimate goal.

5. Be Forgiving But Balanced

Inevitably, we slip up. That's just a part of being human.

Instead of demanding perfection, expect to have some bumps along the road. The important thing is to observe the right trend in the long-run instead of obsessing over every little mistake.

That being said, it's also not okay to just give yourself exceptions everyday. If you do that, you're just not making any meaningful change at all.


The most important lesson I learned from running this personal health experiment is awareness. I have become aware of my body’s behavior and functions. I know how much I tend to eat and how often I exercise.

And that’s huge. Because otherwise, I would be flying blind.

But now that I know my current state, I can make plans to achieve my desired future state. Data from the past informs how I should behave in the present to reach a future goal.

Of course, I still have long ways to go because I recognize that it’s about the journey, not the destination. I hope that even after I’ve achieved my fitness goal that I continue to be healthy. If I fell back to old habits, all my time and effort would simply be wasted.

The new me is conscious of how my choices affect my body.

Now, whenever I want to eat something, it causes me to ask myself, do I really want that entry in my food journal? Accountability.

Now, whenever I feel like skipping a day's exercise, I remind myself that I cannot record the negative counts into my sheet. Gamification.


Jerry Zhang

Programmer, YouTuber, and amateur musician. I like to write too!