Fasting is raising blood sugar and kicking me out of ketosis! Is fasting even worth the trouble?


(Mike D) #1

I see all the benefits of intermittent fasting being claimed as a panacea, but my experience has been counterproductive and I am wondering if it is even worth it to continue.

For the past 9 months on my keto journey I have taken the same approach every day without deviation. I drink a 25g protein shake with 1 gram of carbs. I do not eat again until dinner and I eat all remaining calories at that time. The morning shake is 150 calories and my dinner is 950 calories, for a total daily intake of 1,100 calories. My daily total carb intake is between 10-15grams. I am not sure if this is considered OMAD everyday, but I guess that’s irrelevant.
As long as I follow this same protocol everyday my numbers stay about the same, fasting glucose 12hrs after protein shake is 80-90, blood ketones 2.0 and in the morning after waking urin strips show 5.0 ketones. Weight loss is pretty steady and follows projected math pretty closely.

Here is the problem. I weigh, caliper and take pictures of myself every Saturday, this is my day of accountability. If I did not lose much that week I do a single 24 hour fast on that day to hold myself accountable. I simply withhold the usual 150cal morning shake and proceed to only eat my 950 calorie dinner with no changes. But every time I do this it backfires and does the opposite of its intended purpose.

First thing that happens is that I feel light headed all day, but this makes no sense because the fasting makes my blood sugar shoot up way past normal. When I take my 23hr fasting blood sugar it is around 110. Then it knocks me out of ketosis from my normal 2.0 to about 0.5. I can’t sleep at all that night, feels like I am on methamphetamines, which gives me the hypothesis that fasting jacks my cortisone high and that is causing a domino effect of problems. I finally wake up in the morning day after and am only showing trace ketones on the strip upon waking.

So basically I do pretty good and have consistent numbers UNTIL I fast, which screws up everything, knocks me out of ketosis and makes me look prediabetic.

I wonder to some degree if my extremely strict calorie restriction is part of the problem? I am disabled and do not do even light daily activity, I sit around all day. So my TDEE is estimated to only be about 1,800cal a day. I know my daily intake of 1,100 calories is low enough to make most people shudder, especially maintained over 7 months straight. But my activity level is so darn low, I think this is a deviation from the norm. But I wonder sometimes, because I seem to get these huge cortisol spikes on my Saturday fasting day. Is it possible on that day I am reaching into the level of borderline starvation? And possibly creating a adrenal response that is shifting me into a catabolic hyperglycemic state through aggressive liver gluconeogenisis?

I have lost 65lbs so far on keto, and am now at 16%bf. My goal is to be 8%bf by Oct 15th. I see the finish line and am committed, but it seems the more I fast, the worse my numbers are and my sleep quality is really bad that night.

After I hit my goal, I am obviously going to be adding back in qbout 600calories a day. I thought maybe I should just continue as normal and scrap the Saturday 23hr fast until then. Then maybe once I am in maintenance phase after hitting goal, possibly adding the Sat23hr fast back in…?

Any thoughts everyone? Should I just avoid the fast until after I reach maintenance phase?

(Joey) #2

I didn’t absorb every detail but one thing seems clear enough:

You are starving your metabolism. Losing weight through starvation is counterproductive and ultimately unhealthy. That’s what prison camps are for.

Please reconsider your approach. :vulcan_salute:

(Mike D) #3

Ok thanks, Ill add back in some proteins and fats and will try to lower my carbs under 10g. I should probably just scrap the fasting for now too.

(Polly) #4

Firstly, congratulations on losing 65lb.

I am sure that you are aware of the principles of keto and that satiety through fat burning rather than caloric deficit is the main driver of weight / fat loss.

I agree with SomeGuy Joey that a starvation diet is not a healthy option and you are likely to find it bites back at you.

Had you considered replacing your early morning protein shake with a good breakfast such as a very low carb source of meat or fish and fat - may be scrambled eggs with bacon or smoked fish?

If you wish to continue with restricted time eating (aka intermittent fasting) I have found that having the second meal within 6 to 8 hours of the first meal to be a fairly sweet arrangement. However, I do not monitor my glucose levels or my ketones, I only rely on my trusty bathroom scales and more importantly, perhaps, the fit of my clothing.

FWIW I also eat only real food and avoid most industrially processed products.

Good luck with your future progress however you decide to proceed.

(Mike D) #5

If my Total Daily Expenditure is only 1,900 calories at what level of restriction would you consider to be starvation? Would eating 1,400 (a deficit of 500 calories) still be considered starvation level?


1600 kcal isn’t maintenance for most of us, it’s still too low. 1000 kcal is clearly starvation, with or without much extra fat but with 16%bf it’s not even realistic for you to get plenty of energy from your fat reserves…

As about fasting… It’s not for everyone or at any part of their journey. If you ask me, only do it if you feel fine during it. And if you manage to eat enough.

1100 kcal is too low even for a super short petite girl with zero activity… Unless maybe if people with extremely low natural energy need exist… But for a normal petite girl, 1100 is tragically low. It’s a dangerous amount of food and if you lose fat quickly, eat more and keep losing fat at a less quick pace, it’s fine.
Oh and I get it, you see that your deficit isn’t really huge but it doesn’t work that way. My TDEE is about 1800 kcal too without exercise as far as I could figure it out (these things easily change and actually change day to day, human bodies are like that. mine is pretty predictable though, it’s helpful). It doesn’t mean I could eat 1000 kcal without very bad consequences. People like us should have only a tiny deficit. And I always have higher-cal days too, they may help with metabolism but they surely help with me feeling fine.

About fasting benefits… Even if you don’t starve yourself, there is no guarantee you get the benefits you go for. I never experienced any beyond convenience and lowered energy and protein intake (I badly need both). I do tentatively believe EF would help with autophagy but I eat every day and it feels just normal, I don’t have expectations. it’s like keto: you don’t necessarily get noticeable benefits. And even if the thing is good for you, there are many other factors and maybe you mess up something so you don’t feel as good as normally would. IF still requires you to eat properly.

I don’t measure things so I can’t say anything about that.

And I have no idea what starvation is for you, I doubt it’s so clear, there are many factors… But 1400 kcal surely sounds better. What if you raises it and see if you still lose fat and keep your fat-loss slowish? It’s not that simple for everyone, people with slowed down metabolism may accept gain first… I imagine everyone has a slowed down metabolism after starving for so long. But if you lose fat just fine, your TDEE still can’t be too bad…?

(Polly) #7

This is a good place to start researching starvation and the medium term effects on your body.

(KM) #8

You have a lot of variables here. I don’t know if you’re comfortable sharing info about your disability; both your diet and body fat goals seem extreme but maybe I’m missing an important part of the puzzle? I have a friend with Freidreichs Ataxia, her numbers are also startling but right for her.

As far as your other questions, there is no requirement for carbohydrate in the body,
it will make what it needs, there are many “carnivore” people here who aim for zero carbs. Three carbs isn’t a problem.

I agree that it sounds like OMAD isn’t working for you - and almost like you’re doing it as a punishment. Please don’t! You Can get to your goals and love your body, imperfect or not, along the way.

Looking forward to hearing your story, Mike. Welcome to the forum!

(Peter - Don't Fear the Fat ) #9

Really? … So this may not be directly connected to your question. But surely this is about half what you should be eating?

(Mike D) #10

I have two auto immune diseases, prefer not to get into the details. Long story short, before my long time Rheumatologist retired she said something that she felt would get her fired because it sounded extreme, but bceause she was leaving, she believed it was correct. She said "occasionally someone can send their auto-immune disease into remission by maintaining VERY low body fat levels, levels close to essential fat 6-7% for a man. She said that adipose tissue is actually an endocrine organ that is responsible for creating and mediating most of our body’s inflammatory cytokines. She said you he more body fat someone carries, the more chronic inflammation is present in their bodies and this is why overweight people die early of so many various diseases. She said also that loosing weight in a deep ketosis would further act as an inflammatory mediator. She said it is a role of the dice and not everyone responds, but those that do significantly regain quality of life.

Shortly after she retired I was transferred to her younger colleague. I asked my new Rheumatologist about what she said and she 100% agreed, but it was not PC enough to be talked about openly, so they stay tight lipped on the matter.

I also have fatty liver disease and sleep apnea. Hepatologist also said yes, do what she said. Sleep Doctor also agreed. Primary care doctor also agreed.

All of the above doctors see no problem with a BF as low as 7%. However, the way I have achieved weight loss has been entirely on me. 7-8% is not extreme for a man my age. Low, but not extreme, extreme is below 6% and this is well established across the globe.

I do however think that my level of calorie restriction might be extreme. I only have about 4 weeks left to go, so I will take everyone’s advice and start upping my calories over the next few weeks.

I am not doing it for looks, I do not care what I look like, it is a mission about getting my life back. Does sound like punishment, because I am a Veteran with a militant mentality. Go hard or go home, do it all the way or not at all. Only another soldier would understand this mentality, but we are aware it just looks crazy to outsiders. However, I am not stubborn and open to reason, so if my level of calorie restriction is counterproductive then I will move it up a bit.

One caveat being, I do not think most people truly understand what it is like to be significantly disabled. People go shopping, walk around, clean their house, cart kids around and consider themselves low activity and yet they do absolutely burn north of 2,000 calories a day. But for someone who sits in a chair all day long staring at a tv, or sits in a wheelchair, we do not have the same calorie requirements that “normal” people have. I know it is really difficult to wrap the mind around, because paradigm shifting is difficult for the majority of people. But I can say one thing with absolute confidence… If I go above 1,600 calories my weight loss will stop and at 1,900 the fat starts packing back on.

Yes, severe restriction lowers metabolic rate, but so does sitting in a chair staring at the same wall every day for the past decade. Do I want a slow metabolism, or auto-immune destruction of my quality of life. It is a difficult balance and no matter what I choose I will come out damaged, so just trying to figure it out as I go.


Calories don’t matter on Keto. I ate a ton of calories, mostly in protein and fat, and lost 130 pounds, without exercise. Calories in/calories out is totally irrelevant on Keto. All you will do is screw up your metabolism because your body will go into starvation mode.

I did some OMAD too, but only because on those days I wasn’t hungry. If you eat enough fat, you are sated and only eat when needed. I did on occasion eat more on purpose to jumpstart a stall.

Be kind to yourself.


Your last comment made things more clear, thank you. I didn’t know so very low body fat may be good for auto-immune disease… Yes, it’s a fine bf for a man, it’s just unusually low as it’s not so easy to maintain. Good luck for it!!! You definitely have motivation to do it…

I didn’t know it’s wheelchair level of activity (well some people lift even in a wheelchair as it may affect only their legs but that’s not the point now), I thought of a normal no exercise one. I don’t know how much a tiny bit of walking around the house and similar things burn.
But there is a big individual factor anyway so if you vaguely know your energy need, you can use that number. But if it’s low, I still think you shouldn’t go WAY below, be content with a slow fat-loss. You don’t need to lose so much, it won’t take super long even at a slower pace if you can ensure it will be a slow fat-loss and not zero.

Of course they do. The matter everywhere. I never lose fat on keto because I eat at maintenance. But zillion way longer term ketoers experienced it anyway.
I don’t even understand how a human body would just throw out fat without a reason… Mine surely don’t do that, I need a deficit. As everyone, of course but we with a smallish energy need truly need to eat little for fat-loss. And it’s still fine if we feel right with little food. I am used to huge amounts of food so I just miss fat while overeating fat.
We all have our problems I suppose :smiley:

(Robin) #13

Hi, sorry you are having trouble. The question that stands out to me is why you are only doing this for 4 more weeks. Did I understand that correctly?

Keto is NOT a quick fix, then back to your old ways… keto only works if you are working it. If you go back to your ways after 4 weeks, you’ll likely lose any progress you’ve made and quickly.

Lastly, I agree about needing to eat more. Forget calories and deficits. Concentrate on the carbs and the rest should follow.

Good luck!

(Joey) #14

I didn’t have time to read all of the recent posts in their entirety, but if you want to reduce body fat %, caloric restriction will not succeed. Starvation = loss of muscle (lean tissue) while shutting down metabolic processes to survive. Not good at accomplishing anything.

Eat a diet with mostly healthy animal fat plus sufficient protein (not excess). Yeah, carnivore works nicely for this.

Your body will convert to burning fat - thereby reducing your body fat. You can build muscle through exercise, but burning fat is only achieved by eating TO SATIETY. If you are perennially hungry and undernourished, your body will preserve fat and consume muscle tissue as a survival response.

Best wishes! :vulcan_salute:

(Bacon enough and time) #15

Apparently not, in your case. Go with what works best for you.

(Bacon enough and time) #16

At whatever level your body starts to adapt its expenditure to the amount of food eaten. You can do permanent damage to your metabolism that way, as a follow-up study of “Biggest Loser” contestants has shown. Even on a low-carb diet, the body will hang on to its fat reserves as long as possible, in conditions of famine. So we tend to lose both lean mass and fat mass, when the goal is to preserve lean mass and shed only fat.

The way to achieve the latter is to eat abundantly, and to let the body chose what to do with its reserves. There are plenty of things the body can spend energy on, when there is energy to spend, such as the sex drive, hair and nail growth, and increasing the metabolism of fatty acids. All of these have been demonstrated in scientific studies. Not only that, but that is also the anecdotal experience of many forum members, who report that their fat loss began only when they started eating more, not less.

(Jane) #17

I don’t think you should try to fast at this point in your journey. It shouldn’t be hard or a punishment or make you feel bad.

I don’t agree with your thoughts that 0.5 means you aren’t in ketosis or 110 glucose is pre-diabetic, but it doesn’t matter if you stop fasting.

I agree with the poster that suggested you eat real food (1.e. bacon and eggs) instead of the protein drink and eat your first meal at midday and dinner at your normal time. This will reduce your eating window without the side-effects you experience from a 24-hr fast.

What happens if you do not meet your goal by the arbitrary date you set for yourself? Fat loss is not usually linear for most people and stalls are common.

eta: congratulations on the 65-lb weight loss!


There is simply no point to doing Keto for a period of time and then quitting. You need to switch your body to utilizing fat instead of carbs and keep it that way. There will be a sweet spot for maintenance, that spot tends to be different for all. But, to go back to your old way of eating will undo all you have accomplished. That is not what Keto is, it’s not a fad diet. It’s a change in how your body obtains nutrition.


As I understand the posts, OP has two auto immune diseases that restrict his movements. Did you ever read about Dr. Terry Wahls who claims to have put her MS in remission with diet? I don’t know much more than that.

(Bacon enough and time) #20

Much motor-neuron disease seems to be the result of faulty metabolism in nerve cells, and a ketogenic diet can help by providing ketones and fatty acids as alternatives to glucose.

Not to mention that having sufficient cholesterol available tends to calm down and balance out the immune system.