Nutritional Ketosis and Intermittent Fasting

Over the last week I’ve documented my progress into nutritional ketosis through a ketogenic diet. Yesterday, I added intermittent fasting to that process. Here are the results.

As most of you know, I have advocated for low carb high fat nutrition to reverse metabolic disease since I began practicing it myself in 1999. My understanding of this powerful tool has grown both with my personal experience of it and with the growing body of literature helping to explain the nuances we should all understand. Over the last three years intermittent fasting (IF) has come into it’s own in large part due to the influence of Jason Fung, MD author of The Obesity Code and The Diabetes Code, both books I highly recommend to my patients. I have adopted IF as a personal routine over the last year and have found it extraordinarily powerful at improving my health and well-being.

There are many different ways to undertake fasting ranging from time restricted eating (TRE) to prolonged fasts. TRE is simply not eating for about 12 hours in every 24 hour cycle such as not eating after dinner until breakfast the next day roughly 12 hours apart (8pm to 8am). Most studies don’t consider this true fasting as many of the genes and benefits of fasting are not measurable until one reaches 14-16 hours of fasting.

Intermittent fasting therefore is usually anything lasting 16 hours or longer with the remaining hours used as an opportunity to feed. A 16:8 protocol is nothing after dinner at 8pm until noon the next day. A 20:4 protocol is nothing between 8pm and 4pm the next day. I recommend many of my patients undertake a 24 hour fast weekly or every fourth day depending on the goal. Again, I stress, please don’t undertake this without talking to me first as many times patients need their medications reduced or altered to avoid being over treated during the fasted state.

Yesterday I undertook a 24 hour fast which ended up lasting 27 hours due to the timing of my dinner meals on Monday and Tuesday. Monday night I ate a quick meal of roasted chicken, blueberries, and macadamia nuts then went to exercise around 5:30pm. I didn’t eat again until Tuesday night at 8:30pm. Tuesday’s dinner of 1/2 of chicken, an avocado, and cheese was 5 net carbs.

Throughout the day I followed my glucose levels on my Libre and my blood ketone levels on my KetoMojo meter. As you can see from the Libre readings below, my glucose levels were exceedingly stable and slowly declined throughout the day to a nadir of about 69 mg/dL right before dinner. My meal didn’t budge that number at all.

The ketone readings steadily climbed to some very nice levels throughout the day and have stayed higher than last week even after I’ve eaten several times today. Starting out the day at 1.0 mmol/L they climbed to 1.7 mmol/L by lunch time, 2.7 mmol/L by the end of work, and 3.1 mmol/L by the time I broke the fast at dinner.

Beneficial ketone zones after an overnight fast should be around 0.5 mmol/L or higher. They are are optimal around 1.5-2 mmol/L while eating a long term ketogenic diet. After a prolonged fast they can be around 3-5 mmol/L.

When I fast I tend to feel better and better as the day progresses. The initial hours can be challenging but as the ketones develop the desire for food all but fades to zero and hunger is non-existent. I really enjoy that freedom. The clarity of thought and presence of mind that comes in this state is one of the main benefits I desire from fasting. It brings me back to it again and again and I find myself looking forward to the next day of fasting.

If you’re interested in learning how to use nutritional ketosis, intermittent fasting, or a continuous glucose monitor for its health benefits give me a call. We’ll walk through the process together to ensure your success and safety.

Nutritional Ketosis, Days 5 & 6

I didn’t get a chance to update the daily posts yesterday as the start of school, high school sports practice, and school supply shopping made for a long day. Regardless, the data hasn’t changed much. I had about 29 net carbs Sunday and 22 net carbs Monday.

This produced very stable blood sugar results as shown below.

The spike on August 4th around noon was due to some heavy outdoor work I was cutting down another storm blown tree. The following trend down into the red zone (again not dangerous) was a recovery period. To a degree this is repeated on August 5th at 6pm where I worked out hiking the Hardin Valley hill. During exercise my glucose climbed and then right afterwards it dipped again. That’s an interesting phenomenon that I’m going to have to study more. It happens more often with outdoor exercise than indoor exercise. Maybe the body heat, sweat, and evaporation have something to do with it. This is a good reminder that not all causes of glucose elevation are to be avoided or are harmful. As the body works it wants to fuel the cells and will send glucose out to do that.

My last meal of the day was at 5:30pm yesterday which was some roasted chicken, blueberries, and macadamia nuts. Then I started my 24 hour fast. I’ve tried to incorporate a 24 hour fast into my weekly routine starting Monday after dinner until Tuesday dinner. For various reasons this is the day I’m least likely to eat with my family so giving up a meal doesn’t usually impact our time together. As I write this I just finished up today’s only meal so the fast ended up lasting about 27 hours. I have to say I feel focused and calm more than normal and I have the ketones to prove it. I’ll tell you more about that tomorrow.

So after one week of ketogenic nutrition with daily net carb intake averaging 19.6 gms per day this morning’s ketone level was a solid 1.0 mmol/L. I hope that one week journey into nutritional ketosis show just how straightforward it can be and how it can be implemented in a very busy life.

Tomorrow I’ll share with you my ketone levels throughout a day of fasting. Stay tuned.

Fasting, Irradiation, and Cancer

I wanted to share this week’s email from Peter Attia, MD. It’s a fascinating read about the protective benefits of extreme fasting in mice when they were subjected to a lethal dose of radiation. As he notes in his writing, what happens in mice cannot be directly translated to humans. We’re different species but it helps us develop theories and experiments (that don’t involve lethal radiation) that might prove benefit in humans.

Greetings –

I recently came across an interesting study pertaining to fasting (in mice). The rodents were randomized to ad libitum (i.e., without restriction) feeding or ad libitum feeding followed by 24 hours of fasting prior to the, ahem, “intervention.” Said mice collectively had the privilege of getting blasted with total abdominal radiation at a mega-dose of 11.5 Gy (a unit of ionizing radiation dose) in a single fraction. To get some sense of context here, a CT scan of the abdomen and the pelvis exposes an individual to a relatively high radiation dose, clocking in at approximately 20 milligrays, or mGy (0.020 Gy). This means that for the mice in this study, the absorbed dose of radiation was about the equivalent of 575 abdominal CT scans in one shot.

The average American living at sea level absorbs about 3-5 mGy of radiation annually. So the dose used in the study is almost 3000 times the radiation a person is typically exposed to (and absorbs) over the course of a year.

It therefore might not come as a shock that the non-fasting mice all died within a week from radiation-induced toxicity, akin to humans who have been exposed to staggering doses of radiation (e.g., Hiroshima, Nagasaki, Chernobyl). However, all of the mice that fasted for 24 hours prior to the radiation insult were alive after one month. And while all of the mice, in both groups, showed signs of radiation toxicity, the fasted mice were back to their baseline activity levels 8 days later. The fasting also appeared to protect intestinal stem cells: intestinal epithelial cells in the fasting mice were regenerating by day 10 post-radiation.

The purpose of the study was to find out if fasting could protect the intestines from high-dose radiation, which could allow for higher doses of radiation treatment in killing pancreatic tumor cells. (When patients undergo abdominal radiation the intestines are, due to their rapid turnover of cells that make up the lining, very sensitive to the dose of radiation, and patients are often debilitated by colitis-like symptoms.) Not only did the investigators demonstrate that fasting improved survival and intestinal cell regeneration, they also found that fasting improved the survival of mice with pancreatic tumors also subjected to lethal doses of abdominal radiation. The investigators also noted that the protection conferred by fasting applied only to the normal tissues, whereas the pancreatic tumors were not radioprotected, and actually may have been more vulnerable as a result of the 24-hour fast.

This is not the first time that fasting and/or dietary restriction has been shown to improve the tolerability of toxic cancer therapies (e.g., chemotherapy, radiation therapy). A 2019 review points to several studies in which forms of fasting protects normal cells in mice from the damage induced by chemotherapy and other toxic drugs while differentially making cancer cells more vulnerable.

Of course, what’s true in mice living in laboratory conditions may not be true in men and women living in the real world. I’m doubtful that the study above swung the door wide open for an IRB to approve a clinical trial in humans that includes a lethal dose of radiation. However, fasting is an entirely different story. There already have been a number of feasibility studies in cancer patients showing it is well-tolerated and efficacious.

It’s also worth reiterating (as I try to do every time I make a comment about fasting rodents) that the 24-hour fast in the study above resulted in a 20% loss of body weight. Not a typo. This is about the equivalent of an individual starting a fast this evening weighing 180 lb and dropping 36 lb by the next night. For context, each quarter when I fast for about 7 days, my weight typical goes from about 178 lb to 172 lb or so. (I covered this issue in a little more detail in a previous email.) A 7-day fast is almost universally fatal in mice. In other words, fasting is riskier in mice and generally better tolerated in humans. On the other side of the coin, there is still the question of whether the dose makes the antidote. If a mouse fasts for 24 hours and loses 20% of its body weight, it’s probably not an unreasonable assumption that an equivalent fast for a human is closer to 3 or 4 weeks. (Although, given such dramatic differences, it’s really difficult to say with any confidence if there is a truly equivalent dose of fasting between mice and humans.) Given that the mice in the study received a lethal dose of radiation and survived beyond expectations, could less fasting have sufficed if a more clinically appropriate radiation was given?

That said, given the mounting evidence that fasting appears to be safe and may be beneficial, I would love to see more clinical trials in cancer patients looking at its potential effects, especially given that humans might not need a fraction of the protection the mice needed to survive this study, even under all but the most extreme circumstances.

– Peter

Nutritional Ketosis, CGM Day 2

Wednesday was day two of documenting my journey into a nutritionally ketotic state of metabolism. As I mentioned yesterday, the body stores glucose which must be utilized prior to becoming fat adapted. Certain cellular machinery must be upregulated to mobilize fat from storage and allow it to enter the energy generating chemical pathways more efficiently. This process often takes about 72 hours on a low carb or ketogenic diet and can be accelerated by adding more glucose utilizing exercise along the way or starting from a low carb state of health. Full fat adaption takes nearly 6 to 12 weeks in my experience with patients when they first attempt to transition to a low carb lifestyle. Interestingly, I’ve never had a patient tell me they didn’t feel better having done so. Sure, some revert back to high carb diets for reasons similar to why it so hard to quit tobacco, alcohol, and recreational drugs; they’re addicting. No one goes back to a high carb diet once they truly experience a low carb diet because they felt better in their old way of life and enjoyed being 20 lbs heavier.

My dietary log for Wednesday started with the Kisner Omelette at Nick and J’s Cafe along with black coffee. That’s a hidden menu item created by one of my friends but unfortunately not named for him. It is a three egg omelette with onions, mushrooms, green peppers, tomatoes, cheese, diced ham, and sausage. It is amazingly good. I tend to have mine without the cheese and the carb content is about 11 gms net mostly due to the onions and mushrooms.

Lunch was a simple plate of pulled chicken breast from Archers with a little of their Moonshine Vinegar BBQ sauce and unsweetened tea. BBQ sauces are common culprits for added sugars especially in this area where tomato based sauces are preferred. The mustard based sauces are probably lower in carb content but the vinegar based sauces of North Carolina are likely the lowest. Each sauce can be pretty individualized so check out the labels if you get a chance or ask the cook for their opinion. Lunch was 0 gms of carbs.

When dinner time rolled around I was pretty excited to dig into my dry rub BBQ beef brisket that I was making at home. Over the last year, I have developed a recipe cooking brisket Sous Vide style for 36 hours that allows me to cook a large whole brisket separated into smaller 5-7 lb bags. Once cooked, I freeze what I’m not going to use right away. These can be thawed in the fridge for a day or two then finished in a 225 F convection oven for two hours. It has become one of my favorite meals and at $3.79/lb I can’t beat that price. It doesn’t hurt that my son loves this recipe and asks for it. It can be hard to feed a picky teenager and every little bit helps.

Prior to getting to eat my brisket I felt hungry, or rather, unsatisfied. I took that to indicate that I needed more fat intake. I think this relates to the Rabbit Starvation I mentioned yesterday. With 30-45 minutes left for my brisket to finish in the oven, I ate a cup of Fage whole fat (5%) Greek yogurt. This was 7 gms of carbs but 11 gms of fat and very satisfying. The 10 oz of brisket I ate later was 0 gms of carbs. It’s a moderately fatty portion of the brisket too.

For the day I had about 17 gms of net carbs with the majority of that being from the yogurt and the onions in the omelette. I’ve told my patients for years that once you get to about 20 gms of carbs or less per day that’s about as low as one can go. Even an egg as 0.7 gms of carbs and although many nutritional counters log meats like chicken and brisket at 0 gms of carbs per ounce that’s probably not true. When one eats 16-20 ounces of meat per day there is going to be some accumulation from these small amounts. However, the point isn’t to keep the carbs as low as possible or document every single quarter gram of carbs. The point is to keep the carbs low enough to keep my blood glucose stable and in the normal range.

The net effect of this day of Keto food was a pretty stable glucose reading. I call this a win. The lows, in this scenario, are inconsequential. I’ll talk more about them in another post.

So what was the result the following morning after a night of fasting? My serum ketone level, beta-hydroxybutarate to be precise, was 0.5 millimolar/L. That’s a 0.2 mmol/L increase from the prior morning. Remember that 0.5 mmol/L is the lowest end of the ketosis scale. My goal will be too get in the 1.5-2 mmol/L range.

CGM Experiment: What I learned as a non-diabetic from wearing a continuous glucose monitor – Lily Nichols RDN

Here is a great blog post from Lily Nichols, RDN author of Real Food for Pregnancy and Real Food for Gestational Diabetes and presenter at this years Low Carb Denver. Her presentation on low carb nutrition during pregnancy was a solidly scientific and engaging talk.

This post chronicles her time wearing the Freestyle Libre continuous glucose monitor and a good discussion on what ‘normal’ blood sugars should be for the non-diabetic.

I think there is a lot of good information here to consider for those of us who don’t have diabetes but want to understand the stress our body undergoes when we eat certain food.

I’ll be placing a new sensor on next week and blogging about my journey into nutritional ketosis and possibly the effects of fasting on my blood sugars. Stay tuned for that series although, sadly, there will be less cake involved compared to the first series.

Special thanks to my patient who found this article and shared it with me. One of the reasons I love my DPC job is I get to work with incredible people like you all. Patients who are engaged in their own health journey and challenge me too grow, learn, and apply are simply amazing.

Many non diabetics are wearing CGMs to better understand their blood sugar patterns. Here’s what I learned from wearing a continuous glucose monitor.
— Read on lilynicholsrdn.com/cgm-experiment-non-diabetic-continuous-glucose-monitor/

IDM: Women and Fasting: Top Tips for Women Going Through Menopause Part 2

I’ve seen this same observation time and time again. Since using a CGM with most of my patients I’ve begun noticing how often artificial sweeteners cause a reactionary drop in glucose. Presumably this is from the body producing insulin assuming that the sweet taste represents a usable sugar. Since there is no increase in blood stream sugars the net effect is a lowering. So where do sugars go when they leave the blood stream in that manner? They aren’t leaving the body. They aren’t being used as fuel during exercise. They get stored in a cell. It’s hard to lose weight when the body keeps storing glucose in the cells.

Women and Fasting: Top Tips for Women Going Through Menopause Part 2 – Intensive Dietary Management (IDM)
— Read on idmprogram.com/women-and-fasting-top-tips-for-women-going-through-menopause-part-2/

The Truth Behind What Intermittent Fasting Does to Your Body | Inverse

Studies show intermittent fasting can lead to weight loss, stabilized blood sugar, reduced inflammation, improvements in memory and stress resistance, slowed aging, longer lifespan, and blood sugar stabilization — all promising health benefits in return for considerable lifestyle changes.
— Read on www.inverse.com/article/57625-what-intermittent-fasting-actually-does-to-your-body

Decent article on fasting if you ignore the unsupported semi-vegan dietary recommendation. It’s amazing how one can write an entire article on lowering insulin production through fasting and then ignore that very concept when choosing food to eat. Plants are part of a good dietary plan but most plants are mostly carbohydrates. To lower insulin levels all the time, not just when not eating, you have to lower the carb intake. You can’t build your diet on a non-essential macronutrient and expect to stay healthy.

CGM Day 9 & 10: Minor detour for ice cream

Did great yesterday until the end of the day when I succumbed to the siren call of ice cream after a very long day. The breakfast spike was due to my infatuation with blueberries.

Today was a new day though. I had my typical Wednesday breakfast at Nick and J’s Cafe of three eggs over well with bacon and black coffee. Then I met a friend for lunch at Dickies for 1/2lb of brisket. We celebrated his amazing success on his low carb/fasting journey which I hope he’ll share on this blog sometime soon.

This afternoon there was a handful of green grapes running out the door to go do yard work at the office.

Glory be to God, tomorrow is always a new day.

Day 2 of CGM

Here’s the majority of today’s readings.

You can see small impact of breakfast which was the same 3 eggs and 1/2 cup blueberries as yesterday but no toast or jam. What a difference that made. Note too the dip in my glucose right before awakening and the rise as I got up. The normal stress of standing upright and waking in the morning will raise your glucose some. Notice the good glucose control overnight when the body isn’t trying to metabolize a Star Crunch but is essentially fasted? Powerful.

Lunch was a 1/2 pound of delicious beef brisket. There was no impact or elevation on my glucose. Dry rub BBQ is one of the best options to limit sugar intake as almost all BBQ sauces have added sugar.

The blue arrow indicates an elevated glucose associated with a stressful situation. We should be cognizant that our body responds to stress with elevated glucose. This is why the fourth pillar of good health is peace, or stress management.

Tonight’s dinner is going to be one of my all time favorite meals, Little Joe’s pizza and breadsticks. There’s no doubt what’s going to happen but it will be interesting to see the impact it has. Stay tuned for a full report later on.

Star Crunch and skyrocketing insulin

My CGM experiment started last night when I placed the Free Style Libre CGM at about 7pm. It takes an hour to ‘warm up’ before showing any readings.

As I previously wrote, I’ll be eating foods that I call ‘celebration’ foods during the first week. Generally these are foods I reserve for treats and times of celebration. They are foods that have a clearly powerful impact on hyperinsulinemia (think jet fuel on a bonfire). Being mostly simple sugar and nearly nothing else they drive the blood sugar up extremely fast which drives the insulin up. As insulin goes up all the things you don’t want to happen do.

Star Crunch, Little Debbie’s best treat

So for the prequel to my one week celebration food experiment I decided to document the effect of one of my all time favorite packaged treats, Little Debbie’s Star Crunch. Perhaps, it’s more of an emotional attachment for me as I used to have this food as my 2am reward when I was on call at LeBonheur Children’s Hospital in Memphis. When you’re 20 hours into a 36 hour shift and it’s a struggle to fight off fatigue to answer your pager one more time, sometimes you need little rewards to encourage you through. Ironically for me, but great for the kids, LeBonheur decided they needed to offer healthier food in their cafeteria for the kids and removed all the Little Debbie snacks about halfway through my last rotation there.

Back to my prequel experiment…I had spent the weekend camping with my family and some friends and, perhaps, had started my ‘celebration’ food experiment a few days early without my CGM. However, after returning home Sunday afternoon, I spent a considerable time working outside in the yard including chainsawing some trees that were toppled in Friday’s isolated freak windstorm. I had worked hard. It was time for my reward.

I decided to eat the Star Crunch about 30 minutes prior to going to bed. Studies show that most American’s eat about 15 hours a day consuming something within the hour prior to getting into bed. I thought it would be interesting to see just how bad this habit would be for me.

Here’s the nutritional information for a Star Crunch.

Star Crunch Nutritional Data

The carb calculation for a Star Crunch is 42gms of net carbs. Forty-three grams of total carbs minus 1 gram of fiber. So what was the effect on my blood sugar?

This is disturbing.

As you can see, the Star Crunch eaten before bed caused my body to be hyperglycemic all night. My morning glucose was 103 mg/dL. Incidentally, I didn’t feel well either when I got up. I felt like I hadn’t rested well.

So what’s the take away? Did I learn that a Star Crunch is not healthy? Was I surprised that it made my blood glucose go up? Not at all, I already knew those things. What I learned was to associate the feeling of being unwell with the knowledge of why I felt unwell. Honestly, it made it hard to eat breakfast. I’ve come to enjoy fasting as a corrective measure so much that I naturally wanted to skip breakfast to correct this issue. Yet, I soldiered on and ate anyway. I’ll document that in a post later today. Stay tuned.