If you remember how this dietary experimentation began a few months back, I was searching for better athletic performance without sacrificing blood sugar control. I had been following a low carb diet and it wasn’t really getting the job done for me. I decided to try a low-fat, plant-based approach to see if I had been missing something. It definitely had some benefits and it also had some limitations, further reinforcing the idea that there is no “quick fix” in terms of diet–nevertheless I’d like to re-approach the Ketogenic vs Vegan debate through 7 specific points of comparison and close with a comparison of CGM data.

I wrote an eBook compiling my experiments with the ketogenic diet and type 1 diabetes which you can check out here:


A little over a month ago, I made the decision to go away from the low-fat, plant-based approach and go in the opposite direction by revisiting the Ketogenic (low carb, high fat) diet again.I know people who thrive on a plant-based, low fat approach. I know people who thrive on a low carb, high fat ketogenic diet. I am still learning about where I belong. In upcoming posts I am going to go into greater detail about what I eat specifically, mistakes that I made trying to adopt a ketogenic diet as well as some important strategies to be aware of if you’re thinking about testing the Ketogenic approach with your diabetes. Technically I am writing this in reverse because I’m leading with the summary–I want to start by comparing a few of the following factors between a low-fat, plant-based diet and a Ketogenic diet–as I experienced it.

  1. blood sugar control
  2. insulin dosing requirements
  3. insulin sensitivity
  4. exercise and recovery
  5. portion volume
  6. relative cost of food
  7. body composition

I want to preface this comparison by making clear that I am not trying to get anyone to adopt my methods. Optimization of diet is not right for everyone with diabetes at every stage in the game. Parents particularly have to walk a tough line between the desire to optimize for their child and the reality that survival is often the larger priority.

I do strongly advocate for mindful experimentation and not simply accepting the idea that the war for generally stable blood sugar is one you have to lose just because you have had losses in the past. I absolutely believe that losing those battles is part of the process that we can’t avoid–and shouldn’t avoid. Living in fear of diabetes is the war and that’s the one that we can’t afford to lose. My purpose in writing this is to encourage others through my own trial and error.

Conventional wisdom about diet and diabetes is a starting point. It’s a life-raft, not the rescue. Researching, experimenting and challenging what you’ve been handed is where optimization starts to occur. I believe that time and patience are the only ways we can find out what is right for us–and our own experience is the best teacher. That’s why diet is such a fascinating topic for me–it’s research I can do on my own!

  1. Blood sugar control: I feel as though my control was good on both diets with average BG readings around 120-130. The big difference that I noticed was the amount of attention or mental focus demanded by the low-fat, plant-based approach in order to keep a stable line on my CGM. I had to be aware of what direction my blood sugar was trending and the fact that it would rise and fall much more dramatically. Since adopting the Ketogenic diet I have not seen a single up or down arrow on my CGM. No exaggeration. Not one. Rises are slower and less significant (20-30 points)–and so are drops. In terms of my peace of mind, not seeing arrows up or down (which was a daily occurrence on the low-fat, plant-based diet) cuts out a lot of stress and simplifies my life.
  2. Insulin requirements: My insulin sensitivity increased when I was on the low fat diet. I knocked about 10 units off my total daily dose which was a really significant benefit. Prior to starting up these experiments in the spring I was taking just over 30 units total. Once I went low-fat, plant-based I dropped that to about 22 units. This was one marker I was watching carefully as I then switched to the Ketogenic diet–because I wanted to see if I would go back up to previous insulin levels. My current insulin total daily dose is still 22 units. I do split up my doses a bit more, so it means smaller injections taken with a little more frequency but the total amount of insulin is the same–and still a significant reduction from what I was using before I was adhering to either of these diets.
  3. Insulin sensitivity: How fast and how “hard” insulin works after you inject is as important as how much you need to take to get the desired effect. I felt like the low-fat, plant-based approach saw faster response times following injections. There really isn’t much debate for me on that one. The important consideration however, is that insulin which is working super fast (in the absence of fat) can also be more work in order to avoid lows. I currently am not missing the rapid insulin response because a “high” blood sugar for me currently is about 140-160 and if it takes an hour for that correction dose to really kick in, that’s ok because I am not feeling anxious about the damage being done to my body at those levels. The previous low-fat, plant-based approach would see spikes into the mid 200’s with consistency, even with a pre-bolus on board (especially in the AM) and so the rapid insulin action seemed much more desirable if not necessary at those levels.
  4. Exercise and recovery: This is another category where the low-fat, plant-based approach seemed to have a slight edge. If you are eating fruits and vegetables in high volume, you will be getting a lot of micronutrients that go a long way to aiding performance and recovery. While I still get several servings of low-carb leafy greens each day, I have had to work harder to balance my electrolytes on the Ketogenic diet. I have been dialing that process in and have achieved similar performance and recovery but it does not just come without effort. On the flip side, while I felt like I had an easier time recovering eating only fruits, roots and leaves (low fat, plant-based) I was dramatically hindered by the drastic increase in insulin action and sensitivity–I would have to start workouts at 180 mg/dl in order to “pad the landing” of my inevitable drop. Now I feel fine going for a run with a BG measurement of 120 or 110. I know I’ll probably creep up 10-20 points but that will subside afterwards and I don’t have to stuff my pockets (or my stomach) beforehand.
  5. Portion volume: I fill up a lot faster eating predominately fat for calories. The plant based approach requires frequent feeding–and with each feeding, insulin. I was making a trip to the grocery store literally every other day just trying to keep fruits and salads in stock–now I am able to be a lot more selective about when I eat and not feel hungry in between meals and the big benefit as far as I am concerned, is not having to feel obligated to eat–and take insulin as frequently–and then be on guard against dropping.
  6. Relative cost of foods: This one is highly variable. Greens and fruits are not cheap–especially when you are refilling your supply every other day. On the other hand, high quality nuts, seeds, oils, meats and eggs aren’t cheap either. The difference is that on a high fat Ketogenic diet I am able eat smaller portions of food and make those food items last longer because the volume of food required to feel full and have energy is lower. Ultimately who “wins” this category is about whether you’d rather buy a LOT of medium priced products frequently or some higher priced foods infrequently. I am a frugal person but my diet is not one area where my primary motivation is cost cutting–I have many other areas of my life where I can do that.
  7. Body composition: I lost about 10 lbs. on the low-fat, plant based diet. When I switched onto the high fat, Ketogenic diet I lost an additional 5 lbs. and then leveled out at my target weight (175 lbs.). I feel like this category was a draw for me. Either diet eliminates refined foods–flours, sugars and breads. I suspect that this similarity is one of the biggest health benefits to adopting one of these diets.

Lastly I want to compare a month of CGM data from my plant-based, low fat time against my most recent download having been on the Ketogenic diet for the last month:

Low fat

dexcom CGM for type1 diabetes

High fat

CGM data


To summarize, the Ketogenic diet dropped my BG average by 7 points without having significant lows and although it’s not reported on this readout, I had exactly ZERO “down arrow” drops in BG trends which speaks to peace of mind and ease of management for me. There is also significantly more “headroom” during daytime hours–it’s pretty clear that my BGs stayed more consistently steady during the day given the green that you can see in the middle of the readout on the second image–including days that I would work out. The point of sharing this is to explain that accurate response which mitigates significant and disruptive highs and lows becomes much more commonplace when my diet is working with me instead of against me.

This is a complex topic–and I mean to write a few more posts in the coming weeks about the optimization process and really get into some of the details that I alluded to in this post. In the meantime, I’d love to hear from you steve@livingvertical.org–what did I miss and what would you like to know more about? I’m deliberately not asking you to tell me if you’d rather I shut up and go away–because this isn’t a “diet blog” and there is a lot more in the works that is “more fun” than rehashing diets. I want to give you benefit of my experience such as it is–if that means hanging from a wall in Zion or agonizing over carbs–it’s all LIFE with diabetes in pursuit of adventure.

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