How I ran my own diet experiment—and how you can conduct your own

Serdar Tuncali
Jun 26 · 17 min read
Photo by Jenna Hamra viaPexels.

Ever since I lost 47 pounds to get in the best shape of my life, I was obsessed with the idea of flexible dieting. It worked great for me and I was convinced it was the best diet anyone can follow.

I have continued my quest to learn as much about fitness as possible by following the experts, reading scientific studies, and listening to podcasts. What I realized was that the proponents of the ketogenic diet were swearing by the health effects of this very-low-carbohydrate diet.

Even though the ketogenic diet can provide rapid weight loss in the short term, scientific studies have never shown the superiority of cutting carbohydrates for long-term fat loss (References listed below, or click directly to papers here: 1, 2, 3, 4, 5). But actual people on the diet were claiming that it works better than everything else they’d tried.

The ketogenic diet is also getting popular in the cancer research field — especially brain tumor research (6). Last year, I went to New Orleans to attend the annual meeting of the Society of Neuro-Oncology (SNO). The ketogenic diet was one of the hot topics in this meeting. Even though I haven’t seen any conclusive data, there are some promising results.

I didn’t want to knock it without trying it myself, so I decided to put myself on the ketogenic diet for four weeks as an experiment. I wanted to experience first hand how this diet works so well for so many people.

Even though I am a proponent of the flexible dieting, I did my best to be as objective as possible. I have no affiliations or financial interest from promoting either diet. I was ready to get onto the keto bandwagon if it worked for me.

What Is the Ketogenic Diet?
How does the ketogenic diet help with weight loss?
My Experimental Design
What is intermittent fasting?
My Five Week Experiment: Details and Metrics
Week 0 (Run-in Diet)
Week 1
Week 2
Week 3
Week 4
My Results and Experiences
Bloodwork Results
I lost weight
I kept my strength
I got tired quickly
I lost my motivation
I felt full all the time
No improvements on psoriasis
My Thoughts on the Ketogenic DietHow to Find the Best Diet For YouReferences

I tested my ketone levels with the urine test strips. (Photo by the author.)

What Is the Ketogenic Diet?

The ketogenic diet is a very high-fat, low-carbohydrate diet. It was originally used as a medical diet to manage epilepsy seizures in children. This diet forces the body to use fat as the main energy source instead of carbohydrates.

When you eat carbohydrates, they are converted to glucose molecules, which are then used for energy and brain function. However, if no carbohydrates are available, then the liver converts fat molecules into ketone bodies to replace the function of glucose.

Consuming a very little amount of carbohydrates for an extended time elevates the level of ketones in the bloodstream, which is known as the state of ketosis. Epilepsy patients experience fewer seizures when they are in ketosis (7). However, in recent years, the ketogenic diet has been promoted as a solution to weight problems.

How does the ketogenic diet help with weight loss?

Low-carbohydrate diets have been promoted as weight loss diets for a long time. In the last 50 years, low-carbohydrate diets such as the Atkins Diet, the Dukan Diet, the South Beach Diet, the Paleo Diet, and the Ketogenic Diet have been the most popular weight loss diets. People on these diets swear by them and they are not shy about sharing their double-digit or triple-digit weight loss results.

The idea behind these diets is the carbohydrate insulin model of obesity (8). This model points the finger at insulin as the main factor for fat gain, and it claims that as long as we keep insulin release low by reducing carbohydrate intake, the body cannot gain fat. This model has been challenged, proposing that calorie balance is the single most important factor in weight gain and weight loss (9).

If low-carbohydrate diets are not superior, how is that possible that thousands of people claim to have lost the weight they couldn’t lose on a low-fat diet? That is indeed a curious case, and I wanted to experience the ketogenic diet first hand to understand this for myself.

Being a scientist myself, I approached this little n=1 experiment as scientifically as possible. I want to emphasize that the results of my experiment are not scientifically valid for anyone but me. Diets are very individual, and in order to get conclusive results, we need a large sample size. Even then, the results reflect the average of the group and your individual results might be different.


My Experimental Design

My goal was to test whether the number of carbohydrates makes a difference in terms of body weight. In order to test this with only one subject (me), I need a control group. Since I don’t have an identical twin who could do this experiment with me, I have decided to have a week of run-in diet.

This serves two purposes. First of all, it will give me a week to measure my baseline values. The second purpose is to remove the initial weight loss that happens once you switch to a low-calorie diet that consists of mostly whole foods.

My rules for the run-in week were:

  • Eat as much food as needed to feel full.
  • Avoid highly processed foods.
  • Aim for 30% protein, 30% fat, 40% carbohydrates.
  • 12pm-8pm feeding window.
  • Track calories, weight, strength, sleep, overall feeling.
  • Follow a 3-days-a-week, full-body, weight lifting workout.

After 7 days of this, my 4-week ketogenic diet started.

My rules for the ketogenic diet were:

  • Eat as much food as needed to feel full.
  • Avoid highly processed foods.
  • Aim for 30% protein, 60% fat, 10% carbohydrates.
  • Maximum 50g net carbs (total carbs minus fiber) per day.
  • 12pm-8pm feeding window.
  • Track calories, weight, strength, sleep, overall feeling.
  • Follow a 3-days-a-week, full-body, weight lifting workout.

For the full 5 weeks, I took the following measurements:

  • Weight.
  • Body fat percentage.
  • Waist circumference.
  • Strength on the big lifts (squat, deadlift, bench press).
  • Hunger (calories consumed).
  • Sleep quality and quantity (measured by smartwatch).
  • Mood.
  • Difficulty staying on the diet.
  • Overall feeling.

Even though weight loss was not my primary goal, I wanted to lose some weight during this process. In order to control my calories, I have decided to incorporate intermittent fasting into my experiment.

What is intermittent fasting?

Intermittent fasting is an eating schedule where you fast for a certain amount of time and feed for a certain amount of time.

Whether you know it or not, you are technically doing intermittent fasting every day already. The time spent between your last meal at night and your breakfast is your fasting window. Hence the name breakfast — it’s the meal where you are breaking your fast.

The shorter your feeding window, the less opportunity you have to consume calories. Therefore, you end up feeling satisfied with fewer calories.

My fasting window during these 5 weeks was 16 hours. This means I only had 8 hours to eat. I chose to eat between noon and 8 pm. I broke my fast with a medium size lunch, allowed myself to eat an afternoon snack, and finished with a large dinner.


My Five Week Experiment: Details and Metrics

Week 0 (Run-in Diet)

Weight: 210 lbs
Body Fat: 18%
Waist: 36.5”

During the first week, my meals were mostly lean meat or chicken, vegetables, and carbs (potatoes, rice, or pasta). I also had a snack in the form of nuts or protein bars.

I consumed around 2,200 calories a day on average in the run-in week.
I followed a full-body weightlifting program on Monday, Wednesday, and Friday. Each workout started with a heavy compound lift.

Mondays started with deadlifts, Wednesdays with squats, and Fridays with the bench press. I picked a weight that I thought I could perform 4 to 6 reps for 3 sets, recorded my reps and sets, and stuck with the same weight over the course of the experiment. I wanted to see whether there would be any drop in my strength. My initial lifts:

Deadlift: 325 lbs — 3 sets x 4 reps
Squat: 225 lbs — 3 sets x 6 reps
Bench Press: 185 lbs — 3 sets x 6 reps

I slept 8 hours per night on average, and according to my smartwatch, my sleep efficiency was 90%.


Week 1

Weight: 208.6 lbs
Body Fat: 17.5%
Waist: 36.3”

In the first week of the ketogenic diet, I wanted to keep my diet as simple as possible. For lunch and dinner, I ate fatty meat, chicken, or fish. I had a salad on the side with olive oil and avocado. For a snack, I had nuts or peanut butter. I drank whey protein shakes after my workouts.

I ended up consuming 2,100 calories on average. I didn’t get hungry during my fasting window and my meals were satisfying. Craving was not an issue and I felt like I could do this forever.

On my first day of keto, I immediately lost 3.6 lbs. It was, of course, losing water due to loss of glycogen stores in my muscles.

My workouts were fine and I didn’t experience any loss of strength. I was motivated to workout and able to finish it without any issues.

I slept 8 hours and 4 minutes on average with 91% efficiency.

The only problem was my hike on Sunday. I normally reach the top in 40 minutes or less. This time I couldn’t make it to the top and I had to turn back after 1 hour. I felt so tired the whole time. For the rest of the day, I felt miserable. It felt like I had a bad hangover. I am assuming my body was dehydrated and low on electrolytes. I should have increased my water intake and possibly added electrolytes to my water. Lesson learned!


Week 2

Weight: 202.2 lbs
Body Fat: 16.5%
Waist: 35”

It was shocking to have lost over 6 pounds in a week. At this point, I understand why so many people are raving about the ketogenic diet.

However, I am also starting to understand why so many people fail to stick with the diet long term.

I was craving the foods I was restricted to eat. The cravings were not so bad, but I had a few “keto approved” desserts over the course of a week. I consumed 2,300 calories on average.

My strength was the same during the week, but I was having trouble finishing my workouts. I was feeling drained halfway through my workouts and ended up cutting them short. I also started playing soccer, but I got tired so quickly.

I slept 8 hours and 22 minutes on average with 92% efficiency.


Week 3

Weight: 200.8 lbs
Body Fat: 16.3%
Waist: 34.5”

The rate of my weight loss reached a normal level. At this point, I was no longer losing water weight due to the loss of glycogen. This rate of fat loss is what I normally experience when I get on a diet around 2,200–2,400 calories.

My eating habits didn’t change much, but my cravings got worse. At this point, I would much rather eat a keto dessert than a full meal. I had no interest in the foods I was eating but I was still not feeling hungry. During this week, I consumed 2,100 calories on average.

I wish I could tell you how my strength was being affected. Unfortunately, I had no motivation to workout during this week. I only did my Monday workout, and my deadlift strength was the same.

I could barely get out of the couch or my chair. I was averaging around 4,500 steps per day. Normally I average around 6,000 steps.

This week there were a couple of days I had to wake up very early. Therefore, my sleep measurements got disrupted. However, I didn’t feel any changes in my sleep quality.


Week 4

Weight: 200.4 lbs
Body Fat: 16.7%
Waist: 34.7”

Not losing any weight, combined with the cravings, made it hard to stay on this diet. Hunger was still not an issue because I was allowed to eat as much as I wanted. The actual problem is, in order to satisfy my cravings, I reach for “keto approved” snack foods instead of nutritious meals.

I feel like I am cheating the system in order to stay on the diet. But what is the point? If I am not going to lose fat by eating nutritious, satisfying meals, why am I still following the diet?

During this week, I consumed 2,200 calories on average. I didn’t do my strength training workout. I played soccer one day and that was pretty much it for exercise.

I was gladly ending my experiment, knowing this is not a sustainable way of living for me in the long term.

End measurements:
Weight: 200 lbs
Body Fat: 17%
Waist: 34.6”


My Results and Experiences

Photos by author.

Bloodwork Results

At the end of my experiment, it was time to get my bloodwork done to make sure I was still healthy. I get my bloodwork done every year, so I compared the results to last year.

My bloodwork results show a slight improvement in my fasting glucose levels. However, my blood lipids have been negatively affected by this little experiment.

Illustration by author.

My total cholesterol and LDL numbers had increased significantly, although they were still in a healthy range. My HDL number had dropped, which was the biggest shock to me.

I was expecting my cholesterol to increase, but I was also expecting my HDL to increase. Consuming healthy fats such as avocado, olive oil, nuts, seeds, and fish oil did not increase my HDL levels. However, eating saturated fats such as red meat, processed meats, MCT oil, and butter predictably increased my LDL and total cholesterol levels. My triglycerides are still at a very low level, so I am not expecting to have a heart disease anytime soon.

I am going to get another bloodwork done in 6 months to see if these numbers improve with a diet low in saturated fats. I will update this article once I get those numbers.

I lost weight

I lost over 8 pounds in 4 weeks. Considering the majority of the weight was gone in the first week, not all 8 pounds lost was fat. Following a low- carbohydrate diet causes the glycogen stores to be depleted. Every gram of glycogen holds about 3 grams of water. Therefore, when you lose glycogen, you lose water weight with it.

I kept my strength

This was my biggest concern. Was I going to lose my strength on this diet? Fortunately, I was able to keep my strength on major lifts.

I got tired quickly

Even though I was able to keep my strength, I wasn't able to finish my workouts. I would get tired so quickly, I wouldn't have enough energy to get through my workouts.

I lost my motivation

Towards the end of the experiment, I just wanted to sit in my chair all day. I had no motivation to workout or do anything else. Since my activity level was so low, my weight loss stopped.

I felt full all the time

Hunger was never an issue. It is very hard to overeat on this diet. As long as you stick to whole foods and avoid highly processed “keto snacks”, you will most likely lose weight. However, you need to pay attention to calories burnt.

No improvements on psoriasis

I have a mild form of psoriasis, and I have read about and heard from several people that the ketogenic diet helped their psoriasis. I had no improvements in the 4 weeks I followed the ketogenic diet.


My Thoughts on the Ketogenic Diet

This experiment has taught me that diets are very individual. Success or failure of the diet does not only depend on your genetics but also your personal preference and lifestyle. Even the best diet may not work for you.

My wife decided to give it a shot also when I started the keto diet. She was absolutely miserable for 10 days and didn’t lose any weight. She had to quit after realizing that it was affecting her schoolwork.

Even though I am no longer on the ketogenic diet, I believe it can be very beneficial for someone who wants to lose weight in the short term. If hunger is an issue and you don’t follow a high-intensity workout program, the ketogenic diet might work for you.

I still look at this experiment as a win and I am glad I did it. I now have another tool in my toolkit that I can use at a later time. I know I can get on the keto diet for two weeks and lose over 5 pounds quickly.


How to Find the Best Diet For You

You are probably wondering why there are so many diets out there — it’s because they all work. They may not work for everyone, but they all work for someone.

Instead of trying to find the best diet by reading about other people’s experiences with various diets, you can find the best diet for yourself.

We all have different preferences and personalities. Furthermore, our genetic differences and backgrounds may make a difference as well. Some people can’t handle overly restrictive diets while others need strict rules to be successful.

No matter what science says, the best diet for you will be the one you can stick to in the long term. Significant weight loss results happen anywhere between 3 months to a year. However, you will gain the weight back once you go back to your old habits. Therefore, the diet you pick to lose weight needs to be effortless and sustainable.

Here is a guide for you to conduct your own diet experiment to find the best diet for yourself:

  1. Know your starting point: Give yourself a week to assess your body, your diet, and your activity. Consider this a self-audit. Weigh yourself every morning for a week to notice how your weight fluctuates. Track the foods you eat when you are not on a diet. Use an activity tracker to measure how many steps you take on average. This will give you a baseline to compare.
  2. Set appropriate expectations: If a diet promises you will lose 30 pounds in 30 days, stay away! The ideal rate of weight loss is between 0.5–1% of your weight per week. Anything more than that, and you’re losing precious muscle and lean tissue along with fat. Unless you are an athlete trying to make weight for a competition, your goal should be fat loss, not weight loss. The maximum amount of fat loss without muscle loss is between 0.5–1% of your weight (10). If you have a lot of weight to lose, aim for the higher end, if you are relatively lean, aim for the lower end.
  3. Pick a diet (any diet): The bad news is, there is no single best diet for everyone. You can stop your search for that now. The good news is, whatever diet you follow for a year, you will get results. Instead of white-knuckling through a diet that you hate, pick a diet that you think you would enjoy. During the diet, on a scale of 1 to 10 (1-starving, 10-stuffed), you should feel between 6 to 8. Keep yourself hydrated and snack on low-calorie fruits and vegetables to keep your hunger in check. The occasional feeling of hunger is acceptable on a fat loss diet, but you shouldn’t feel ravenous.
  4. Keep tracking: As you follow your new diet, keep tracking your weight, your food, and your activity level. Even if the diet you picked doesn’t require you to track your calories, do it for a while (at least a week). See if the diet is helping you effortlessly consume fewer calories than before. Are you consistently losing weight? Do you move more or less? Pay attention to how your weight change correlates with your calorie consumption and movement. Remember, the rapid weight loss in the first week is not a good indicator of fat loss.
  5. Don’t blame yourself if it doesn’t work: It is very common to blame yourself when you fail to lose weight on a popular diet. “How come all these people lose weight on this diet, but I fail? It must be my fault!” First of all, the success stories you hear about a diet is a self-selecting group. They talk about their success because they like the diet. The ones who fail rarely talk about their failures. If you can’t lose weight on a particular diet, that diet is probably not the ideal diet for you. You can start again next Monday, but chances are you will fail again down the road.
  6. Assess your feelings: Starting a new diet can be exciting. You start highly motivated, arrange your life to get ready for the diet, go grocery shopping for the foods you are going to eat. However, life doesn’t always work that way. You won’t always be as motivated. There will be stressful times. Some days you will come home too tired to cook. You will be invited to an event with food and drinks. Furthermore, as you lose weight, your body will fight back through a process called adaptive thermogenesis. Are you able to stick to your diet through all these? Do you feel like you can stay on this diet as long as you need?
  7. Maintain: Once you determine the best diet for you and get the results you want, now it’s time to maintain your new weight so you don’t go through all these steps again. Don’t think that your diet is over once you reach your goal weight. If you have been restricting your calories to lose weight, once you achieve your goal, you can slowly increase your calories to a point where your weight is stable and you feel comfortable. If the diet you picked did not restrict your calories, yet you lost weight, stick to the rules of the diet and listen to your body’s hunger signals.

Conducting your own diet experiment does take some time and effort. But what I learned by trying a ketogenic diet for myself was far more valuable than anything I could have read about it.


References

  1. Volek, J. S., Sharman, M. J., Gómez, A. L., Judelson, D. A., Rubin, M. R., Watson, G., … & Kraemer, W. J. (2004). Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women. Nutrition & metabolism, 1(1), 13.
  2. Samaha, F. F., Iqbal, N., Seshadri, P., Chicano, K. L., Daily, D. A., McGrory, J., … & Stern, L. (2003). A low-carbohydrate as compared with a low-fat diet in severe obesity. New England Journal of Medicine, 348(21), 2074–2081.
  3. Sacks, F. M., Bray, G. A., Carey, V. J., Smith, S. R., Ryan, D. H., Anton, S. D., … & Leboff, M. S. (2009). Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates. New England Journal of Medicine, 360(9), 859–873.
  4. Johnston, C. S., Tjonn, S. L., Swan, P. D., White, A., Hutchins, H., & Sears, B. (2006). Ketogenic low-carbohydrate diets have no metabolic advantage over nonketogenic low-carbohydrate diets. The American journal of clinical nutrition, 83(5), 1055–1061.
  5. Naude, C. E., Schoonees, A., Senekal, M., Young, T., Garner, P., & Volmink, J. (2014). Low carbohydrate versus isoenergetic balanced diets for reducing weight and cardiovascular risk: a systematic review and meta-analysis. PloS one, 9(7), e100652.
  6. Seyfried, T. N., Shelton, L., Arismendi-Morillo, G., Kalamian, M., Elsakka, A., Maroon, J., & Mukherjee, P. (2019). Provocative Question: Should Ketogenic Metabolic Therapy Become the Standard of Care for Glioblastoma?. Neurochemical research, 1–13.
  7. Barañano, K. W., & Hartman, A. L. (2008). The ketogenic diet: uses in epilepsy and other neurologic illnesses. Current treatment options in neurology, 10(6), 410.
  8. Ludwig, D. S., & Ebbeling, C. B. (2018). The carbohydrate-insulin model of obesity: beyond “calories in, calories out”. JAMA internal medicine, 178(8), 1098–1103.
  9. Hall, K. D., Guyenet, S. J., & Leibel, R. L. (2018). The carbohydrate-insulin model of obesity is difficult to reconcile with current evidence. JAMA internal medicine, 178(8), 1103–1105.
  10. Helms, E. R., Aragon, A. A., & Fitschen, P. J. (2014). Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the international society of sports nutrition, 11(1), 20.

Better Humans

Better Humans is a collection of the world's most trustworthy writing on human potential and self improvement by coaches, academics, and aggressive self-experimenters. Articles are based on deep personal experience, science, and research. No fluff, book reports, or listicles.

Serdar Tuncali

Written by

Scientific approach to fat loss and body transformation. Self-experimenting and researching various methods and reporting on https://nerdgettingfit.com

Better Humans

Better Humans is a collection of the world's most trustworthy writing on human potential and self improvement by coaches, academics, and aggressive self-experimenters. Articles are based on deep personal experience, science, and research. No fluff, book reports, or listicles.

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