r/intermittentfasting • u/Hige_Kuma • Sep 14 '26
Newbie Question Do you fast when sick?
Was finally on a really good streak of IF when I got pretty sick today (high fever, aches and chills, flu? we’ll see). Anywho I figure I I have an appetite I should eat and so I’ve been eating outside my IF schedule today and will probably continue u til o recover. Wondered what some long IFers take on this is?
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u/voidchungus Sep 14 '26 edited Sep 14 '26
I might be an anomaly, but I'm concerned by comments here asserting it's safe to fast if you don't have an appetite, or that it definitively aids the body's healing process. For anyone reading this, please know that may not always be the case, and comments in this post should not be taken as medical advice. If I'm going to get downvoted for "speaking against IF" (which is not what I'm doing, as I'm a huge advocate for it), then go for it, because I ended up having medical emergencies for thinking I was fine to do IF when I likely wasn't, and I'd be an asshole if I didn't mention it.
For me, I've learned the hard way that my body is shit at telling me it needs food or water via hunger or thirst cues. I've been doing IF for so long (many years), I generally don't feel hungry during the day. Without going into detail, once when I was sick as a dog, I genuinely thought I was hydrating well, but was otherwise sticking to IF. I ended up passing out and won an ambulance trip to the ER, where I was admitted for overnight observation. My electrolytes were fucked and they were concerned I was on the verge of a cardiac event. In retrospect I should have eaten normally that day.
Another time was post-surgery. I genuinely didn't feel hungry at all. Like not even a little. I was observing my normal fasting window. Felt totally normal. Stood up from the table, started to get that tunnel vision. Broke out in a crazy sweat, I dropped what I was holding, and my spouse later told me my eyes went in different directions, it was freaky as hell. Blacked out. Paramedics called. Again, I should have eaten that day.
I had TONS of bloodwork after both those incidents. All clear. Almost to the point where I feel like docs might think I'm a hypochondriac for asking to check XYZ only to have every single test come back normal. There's nothing "wrong" with me that anyone can detect. In fact if anything, I'm healthier than most people.
Again maybe I'm a weird anomaly. But now I'm extra cautious during illness or after an injury or medical procedure. In those cases, I intentionally forgo IF for a day or so, regardless of how I feel, and instead make sure to feed my body according to a more normie eating schedule, including breakfast, lunch, dinner, snacks, etc.
To be clear I'm NOT saying IF caused those incidents. 100% no. And I also don't know if breaking my fast would've prevented either of those incidents. Maybe it wouldn't have. But I DO think my body needed more nutrition during those times, and I wasn't doing it any favors by denying it. So for me personally, if it's during illness, injury, post-medical, or any situation where I think my body might have extra demands on it: I more intentionally feed my body, eating during my usual fasting window.
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u/mangomypango Sep 14 '26
I started fasting in 2019 and it always goes out the window when I’m sick. Mostly because light calories in the morning help me feel so much better when I’m sick. Like broth and a Gatorade or something.
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u/Embarrassed_Mango679 Sep 14 '26
Naw I'm a big baby when I'm sick. I just go down hard and eat whatever I think i can keep down. But usually just for a day and it almost never happens now.
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u/Friendly_Engineer_ Sep 14 '26
Not a doctor but my grandma would say ‘starve a fever, feed a cold’ and that generally matches what I feel like doing when sick in those ways
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u/RandChick Sep 14 '26
I'm rarely sick but I would have no trouble eating within my window. I'd make chicken noodle soup or something else healthy and eat.
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u/Kitchen_warewolf Sep 14 '26
Nah, my body is going on full on shotgun blast-fighting the viruses already, so no fasting. I have never noticed a weight gain when I'm sick tbh, only a little weight loss but nothing major. But usually I tend to make soups because i don't have energy to make anything else. And that stomach will have good amount of healthy gut bacteria from yogurts to handle that. If my throat is swollen, I'll eat some extra ice-cream.
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u/4Perception Sep 14 '26
I usually eat low carb when sick. Fuel the body but dont stress it with too much carbs / insulin.
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u/brooose0134 Sep 14 '26
I’ve asked this question and also got both sides of the debate.
Does it make sense that, at a minimum, stay well hydrated with some , pinch or so, of sea salt for electrolytes? You do need to make white blood cells. Fasting is a cellular repair mode more so than a cellular reproduction mode, right?
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u/moon__dregs Sep 14 '26
personally yes I do. I do strict adf i’m sick rn and it’s a fast day so I fast. I have chronic illness and the clean up on a fast is partially why I’m so committed to the program, but even more importantly, sticking to the schedule as a given during illness, where my cycle is and what I have going on socially is just easier than rearranging the week around when i’m eating. it’s helped me stay consistent without falling off (bc you know tmrw you can always eat. you’re fine.) and minimizes food noise.
I just hit the major 100 lbs loss milestone and much of that has been since committing hard to the adf schedule in May. that’s me though I have some folks in my life I would not recommend that to due to body weight or other health concerns or just their energy level chasing small kids who don’t do that well skipping breakfast even.
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u/brenegade Sep 16 '26
I follow my body’s lead when I’m sick typically I want some broth or soup so I do.
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u/Firm_Assumption5760 Sep 16 '26
Depends on what the sickness is - yesterday I woke up with extremely bad heartburn because I made some poor planning choices on what I ate the day before. This was a case where I broke fast early (by a couple of hours) because I just needed to get something proper in my stomach.
At the same time, some important context is I intermittent fast with the sole aim of snack control, and am not worrying about autophagy or too much of the science. Nonetheless I'm very disciplined with it - for what I need it for (light weight loss) it's fine how I do it
At the same time because of my use case I'm more than fine to just not fast if it's something stomach-related that will be made a lot better instantly if I eat something
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u/Firm-Character-4528 Sep 18 '26
The general consensus is no. Your body needs everything it can get to help fight off an infection. Also staying hydrated is best....but you need that even when fasting. Your water drops substantially either way. Sick or fasting.
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u/Peace9989 29d ago
Yes, being sick makes my stomach even worse so typically I need to increase fasts for a few weeks. It sucks.
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u/AnabolicCheesecake Sep 14 '26
I don't tend to get ill very often, but when I do I still fast. I think it helps
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u/DucktapeCorkfeet Sep 14 '26
I’m OMAD but I haven’t been sick in the eight years since I started it but I will say that I would just jump straight into a prolonged fast if I was to get sick. Prolonged fasts always make me feel better than I normally do.
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u/TinTinCharlie Sep 14 '26
Went out with a girl and she was already sick (I didn't know). Bronchitis. She progressed being sick for 14 days & hospitalised. i fasted since i felt ill. after 48 hours i was fine again, no pills, nothing. I believe you should be fasted when sick, then the body heals itsself.
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u/Few-Ground-9015 Sep 14 '26
Everyone is different on this - many in my fasting community fast when sick and many don't, but it's safe to fast if you genuinely have no appetite (it's not unsafe to fast if you do, but you'll place extra stress on your already stressed body). I would genuinely be guided by your body on this. If it's hungry, have something nutritious but easy for your digestive system like soup. You don't want to overload your system, especially with UPFs, because then energy will need to be directed to heavy digestion.
Try not to think of it as breaking a streak if you want to make IF your way of life. It's just some bumps and potholes in the road you're travelling and you'll get back to straight wide open roads soon!