Richard Sprague

My personal website

Keto Experiment

Created: 2020-07-18 ; Updated: 2020-07-20

[This is a sloppy post that I’m putting out here just to get my notes together before I write it up for real]

I’ve done several experiments where I measure my ketone levels: Prolon 5-day fasting mimicking diet, my SIBO issue, and during a few short fasting periods.

During July 2020, I tried a bona fide ketogenic diet for about 10 days, followed by a blood test.

Conclusion: Giving up carbohydrates is harder than you’d think — even something as simple as a banana can throw you off — but it’s not that hard once you get the hang of it. I slipped into ketosis relatively quickly — ketones start to show up in less than two days. A full blood panel at the end of 10 days showed a huge plunge in my triglycerides: my lowest ever, less than half the levels of a year ago, and lower even than during the years when I used to take cholesterol-lowering simvastatin.

The side effects of fatigue and then bad breath started a day or two later; next time I’ll drink more liquids and perhaps take salt or B12 supplements.



The basics

A ketogenic diet assumes you eat per kilogram of body weight:

For me (75 kilos) this translates to

Which seems like a lot of fat calories, but if I can’t increase carbs, then to maintain a sufficient number of calories for the day, you’ll need to increase either fat or protein and fat is much easier.

I hear conflicting advice about the carb portion. Should I shoot for an absolute number of carbs (many people say under 40 or even 20g per day), or should I look at a percentage of my daily calories? For example, if I eat 2200 calories / day, then I should shoot for

which is considerably higher than a fixed amount that people have suggested per day.


After a few weeks of ketosis, most people see a drop in their blood ketone body levels (BHB).

Keto adaptation is a different, deeper phase of ketosis that happens after about a month when the body learns to run effectively on fats. Supposedly it takes about 2-4 weeks to adapt, during which you may feel some “keto flu” and “metallic breath” but after about a month you’ll notice better endurance, energy, and clearer thinking.

Upon adaptation, some people notice low glucose levels (under 75, perhaps as low as 50) yet with no fatigue or hunger.


Basal Metabolic Rate

How many calories I need depends on my BMR, which you can calculate here:

Basal Metabolic Rate (BMR) and Daily Calorie Needs - Calculator Online (Harris-Benedict equation)

My BMR is between 1300 and 1600, and my calorie needs are between 2200 - 2700 depending on how much exercise I do. Although I don’t have a job that requires me to be physically active, I do tend to walk around a lot and generally spend at least 20 minutes per day at double my resting heart rate.


Day by day

Day 1 (Monday July 13)

No breakfast

Later I had a ripe banana with several tablespoons of nut butter.

Mid-day I had a spinach salad and about a cup of quinoa.

For dinner I had a large amount of chicken and some mixed vegetables.

Day 2 (Tuesday)

This is the first day I checked my GKI. My last “serious” carb meal was two nights ago, when I had some pasta.

I ate one more banana

Dinner was a ribeye steak and a healthy amount of tomato bruschetta

Day 3 (Wednesday)

Instead of testing myself immediately after waking, I about two hours after my morning (almond milk) latte and brisk 30-minute walk. The resulting readings show I’ve slipped comfortably into ketosis.

I ate a big breakfast: 2 eggs, a ton of spinach, plus some kimchi.

But man am I sleepy today! I could barely keep from napping in the afternoon, and I was Fatigue is apparently an early sign of the body’s transition. Apparently fatigue is a common side effect during the transition from carbs to keto.

Dinner was pulled pork and a big green salad.

Day 4 (Thursday)

GKI is a bit higher, though I’m measuring it first thing in the morning today.

A big breakfast: gobs of spinach, plus three eggs and topped with half a cup of chopped walnuts.

I think I have noticeably bad breath. The fatigue I suffered on 07-14 was entirely gone yesterday but may have returned this morning. (my GKI is 5.9 an hour after coffee, no exercise)

Day 5 (Friday)

Another big breakfast: chopped squash with onions, more walnuts, and two eggs.

Mid-day I had another large salad with sardines, some cheese, and plenty of nuts.

Sashimi for dinner

Then I had a 16oz Pint of draft high quality beer. Although it didn’t affect my carbs much, the 3.9% alcohol is a bad idea for a keto diet.


Day 6 (Saturday July 18)

Last night’s beer gave me a bit of a headache this morning, but I solved it by drinking lots of water in the morning.

Somehow in the afternoon I found myself drinking a Starbucks Chai Tea, and although it was supposedly low sugar, the Tall size contains 30g of carbohydrates. I drank maybe 3/4ths of the thing.

Day 7

Day 8

Day 10 Tuesday July 21

Day 11

Day 12 Thursday July 23

July 24: Blood test


What I learned

One solution to the fatigue is electrolyte supplements, including salt. Bone broth is good too.

https://theconversation.com/keto-diet-heres-why-some-people-experience-fatigue-nausea-headaches-after-starting-it-135911

But reducing insulin causes an increase in circulating fats that displace an amino acid, called tryptophan, from its carrier. This circulating tryptophan causes an increase in serotonin in the brain and the increase in serotonin results in fatigue, even when you aren’t exerting yourself much.

Restricting carbohydrates acts as a body stressor by stimulating the release of cortisol. Because that much cortisol released can result in “cortisol fatigue”, your body becomes more susceptible to infections like the common cold.

Or maybe take some Vitamin B5: https://www.drberg.com/blog/what-to-do-when-you-get-fatigued-on-the-ketosis-diet