Home Metabolic Dietary Therapy: Fasting, Keto and Functional FoodsFasting Extended Fast Results: 167 hours of nothing exciting

Extended Fast Results: 167 hours of nothing exciting

by Maggie Jones

Read the background and my goals for this fast here.

Day 1: Wednesday

Since I’m used to going a full day without eating every week, Day 1 was nothing new.

Blood GlucoseBlood KetonesGKI

This GKI is awful for me and I knew it would be after the weekend in LA, exhaustion from travel, and heavy indulgence the previous night – it was my last time eating for a week, after all.

Consumed: Water, green and herbal tea, meds/ selected supplements (beta glucans, IP-6/ Inositol)
Weight: 61.6kg (that was a couple days ago but I forgot to weigh today)
Activity: 48 minutes walking, 12 of those brisk
Poops: Massive but easy morning poop courtesy of previous night’s feasting. You’re welcome for this update.

Day 2: Thursday

I know from experience that days two and three are the most difficult but this one was pretty easy. I’m still sick and tired from all my travels. Mostly I want sleep.

Blood GlucoseBlood KetonesGKI

Consumed: Water, green and herbal tea, apple cider vinegar, meds/ selected supplements (beta glucans , IP-6/ Inositol)
Weight: Didn’t weigh
Activity: 35 minutes of mindfulness yoga, 110 minutes walking, 66 of that brisk
Poops: Regular, thanks for asking.

Day 3: Friday

Day three of a fast is normally the most difficult day for me but not much notable today. Went to work; didn’t eat anything. Came home; didn’t eat anything. Fasting is so easy.

Blood GlucoseBlood KetonesGKI

Consumed: Water, green and herbal tea, apple cider vinegar, salt, meds/ selected supplements (vitamin D3 , IP-6/ Inositol )
Weight: 63.2kg (+1.6kg) 3 pounds gain, you say? No worries, it’s just water weight from my edema
Activity: 35 minutes of mindfulness yoga, 117 minutes walking, 26 of that brisk
Poops: According to my personal cancer recovery tracking journal, “Very satisfying morning poop considering no food in 60 hours “

Day 4: Saturday

The most notable thing about this day is that I stopped at Starbucks while running errands to treat myself to a decaf Americano. I noticed they had nuts I could eat and almost ordered them – NOT because I was hungry but because I totally forgot I was fasting. How crazy that I can go four days without eating and not have it be top of mind? I sat in the coffee shop savoring my treat and wasn’t the slightest bit tempted by the cakes and frappuccinos at every other table. Total zen mode.

Blood GlucoseBlood KetonesGKI

Consumed: Water, green and herbal tea, decaf coffee, apple cider vinegar, meds/ selected supplements (beta glucans, vitamin D3, IP-6/ Inositol)
Weight: 63.0kg (-0.2)
Activity: 70 minutes of mindfulness yoga, 130 minutes of walking, 39 brisk
Poops: Amazed to have a normal morning poop after 3 full days with no food.

Day 5: Sunday

I was a little lower energy today and spent some time looking at recipes and planning how to break my fast. I realized that wasn’t a great strategy so switched to reading Dr. Fung’s The Complete Guide to Fasting. I feel like my concentration has seriously improved. I was much more focused while reading and during my daily meditation.

I used my totally blank canvas of a body to test my exogenous ketone supplements. After taking the evening blood measures below, I took the pills and measured again 30 minutes later. My blood ketones were up from 5.0 to 6.1 so okay, it’s not BS.

Otherwise, I saw a massive improvement in my edema and stayed up past 9pm for the first time all week.

Blood GlucoseBlood KetonesGKI

Consumed: Water, green and herbal tea, apple cider vinegar, salt, meds/ selected supplements (beta glucans, exogenous ketones, IP-6/ Inositol)
Weight: 59.0kg (-4.0) My edema finally receded which means my kidneys are feeling a bit better. I credit the fasting.
Activity: 30 minutes mindfulness yoga, 71 minutes walking, 21 of those brisk
Poops: Nope. Finally break time for the digestive system.

Day 6: Monday

Back to work. Monday is a standard fast day so no sweat here. For the first time ever, my ketones were too high for the Keto Mojo to measure – sweet! I feel mostly recovered after a weekend of rest (lymph nodes swelling is reduced and edema in check).

In the morning, I noticed a super thick, white coating on my tongue. It took a lot of scraping with the tongue scraper to remove it all. Some googling tells me this is normal during longer fasts; it’s just the accumulation of dead cells that are normally swished away and swallowed in the process of eating.

I was feeling a little low energy in the evening so made some chicken broth from organic, pasture-raised chicken bones, Himalayan pink salt, turmeric, black pepper and distilled water. Ergo, I technically broke my fast at 142 hours. Nevertheless, Dr. Fung allows his fasting patients to drink stock so I’m not counting it, either. I felt energized after drinking it and realize now that, despite my supplementation, I may have needed the electrolytes.

Blood GlucoseBlood KetonesGKI
Morning71> 8.0<0.5

Consumed: Water, green and herbal tea, apple cider vinegar, salt, meds/ selected supplements (beta glucans, IP-6/Inositol)
Weight: 58.3kg (-0.7)
Activity: 55 minutes mindfulness yoga, 103 minutes walking, 25 of those brisk
Poops: Zero. Digestive system is finally on holiday but available over email and slack.

Day 7: Tuesday

Tuesdays I work from our Tai Po office out in the boonies and need to leave before 7:30am to make it there by 9 via bus, train and 35 minute walk. My energy levels were good all day and I took an extra walk in the park at lunch. Still no signs of hunger.

Blood GlucoseBlood KetonesGKI

Consumed: Water, green and herbal tea, apple cider vinegar, salt, meds/ selected supplements (beta glucans, IP-6/Inositol)
Weight: 57.3 kg (-1.0)
Activity: 114 minutes walking, 49 of those brisk
Poops: Zero but I feel one brewing which is interesting.


Given my past experience, this wasn’t really a long enough fast for it to matter, but to prevent a potentially dangerous condition called “refeeding syndrome,” it’s a good idea to follow these protocols:

  • For the first refeed, limit yourself to 10 calories/kg of body weight per day (or 5 calories/kg for fasts longer than 15 days), with a daily increase of 5 calories/kg .
  • Take supplemental electrolytes (sodium, potassium, calcium, phosphate, and magnesium) and B vitamins at least 30 minutes before eating. In my case, I took a multivitamin. In bro-science terms, this is to ensure your nutrient-depleted body has what it needs to digest your first meal without pilfering from more critical systems.

I broke my fast with broth and avocado mashed with flaxseed oil, sauerkraut, and raw garlic (it sounds gross but it’s a go-to that I love) followed by some nut butters once I was comfortable everything was working.

Experience Summary

I felt no hunger or negative effects during the entire week-long fast. Despite being the longest, this was one of my easiest fasts to date. Being home alone and under the weather probably helped minimize any urge to eat. I’m sure practice helps, too.

The biggest benefit I experienced is a slight return of the mental clarity and focus that I lost as a result of either the lorlatinib, brain tumors, or radiosurgery.

Overall I’ve met my goals: I feel healthy again and my immune system was fully refreshed.

Back to feeding and layering on the fat that will power my next fast!

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Laura Chesher January 2, 2021 - 2:26 pm

How did you decide which supplements to continue during your extended fast? I have metastatic breast cancer and did a 48 hour fast for the first time with a new chemo and herceptin this week. I am wondering if certain or all supplements would be helpful during a fast coinciding with treatment. Thank you.

Maggie Jones January 2, 2021 - 6:14 pm

Hi! My general rule it to only take 1) physician prescribed meds and 2) electrolytes on longer fasts. I have all the deets including how to manage electrolytes at https://cancerv.me/2019/08/28/how-to-fast-and-why/ I hope it’s helpful!!

Sam May 5, 2022 - 11:13 am

The meter topping out at 8 for ketones always makes me a little nervous! Is there any evidence suggesting detrimental effects of very high keystones in a glucose lowered state?

Thanks! Sam

Maggie Jones May 6, 2022 - 3:56 pm

Hi Sam! I don’t have any research off-hand but generally it’s considered a very poor idea to have ketones above ~5 mmol/L. After achieving <1.0 GKI, I haven't heard of any benefits of going lower. I personally don't experience any major issues the few times I go 6+ but I don't do it often or intentionally. Good luck!

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