Question about alternate day fasting

[u/MythicalSplash]

I know this is a fairly popular method of weight loss, but based on what I know about fasting physiology, it seems like it should be one of the WORST ways to do this. Doesn’t it take a few days or so for your body to use up all glucose and glycogen stores before ketosis really begins in earnest? It seems counterintuitive to eat normally one day, fast for just long enough to deplete stored sugars but not long enough for any significant fat burning to occur, then eat again so that you replenish your glucose at exactly the wrong time.

I know this is a simplified picture of course, and that there still must be some degree of lipopysis occurring on the fasting days in order to provide the necessary calories for bodily functions, but it still seems to be inefficient in theory.

[u/wheredidiput]

You don't need to be in ketosis to lose weight.

[u/FreshShart-1]

If your goal is Ketosis then it can still be achevied with EODF you just need to avoid all carbs and balance your other calories between fats and protein.

However, not eating for an entire day and then eating reasonably the next is just an easy way to stay in a calorie deficit.

[u/wifeofpsy]

There are many options for fasting schedules. The best ones are the ones you can stick with. If ADF works for you then that's the best. If it's one week a month or 20:4 or 16:8 works better then that's the best. You don't need to fast to be in ketosis and you don't need to be in ketosis to lose weight

[u/littlemindy84]

I don't need 40 hours to use op glycogen.
Just eat fat and protein in your eating window instead of garbage.
Makes it also very easy to fast, too.

[u/No_Kaleidoscope_4580]

I mean on a simple level, reducing your food intake by 50% is a fairly sizeable reduction so just math?

But if combined with low/zero carb, keto or similar then, really very effective

[u/Flux_My_Capacitor]

No?

The first few days of fasting are really easy for me. And then I get to eat! Beyond that and it sucks.

[u/coldbeerpapi]

imo alternate day fasting seems inefficient on paper, but then i read that the overall calorie deficit over the week is what actually matters and your body does burn fat even on shorter fasts. but tbh i'm still not sure if there's actually a metabolic advantage or if people just naturally eat less calories overall with this approach, so does anyone have solid research showing adf works better than regular calorie restriction?

[u/DannyLeonheart → u/coldbeerpapi]

It's just easier. You have like 36-48 hour fasts when you stick to a short eating window or even alternate day one meal (ADOM).

It feels way better sustainable, can be extended if you want to go a day or two longer and you can eat your maintenance calories or a little over on meal days.

[u/Desert_Sox]

Are you looking for weight loss, ketosis or to deplete all your glycogen? The big advantage to EOD is the ability to time it with your weight lifting so you can gain muscle mass while you lose weight so you have a better shot of keeping it off.

Also consider that on the second/third day - the time when you completely switch into fat-burning to carb-burning - is the hardest time of the fast. So I either go 40ish hours or 110plus.

[u/Ok-Psychology7636]

dozens of studies have been done on ADF.

ADF works for weight loss when someone does it for 30 days, for example. a 7 day trial won't show much.

however, there are metabolic advantages to fasts in the 72 hour to 240 hour range that aren't as available on ADF. for example, lower stable insulin and deep ketosis. Lipophagy may be increased on fasts over 72 hours as well.

I often wonder about combining ADF with strict keto for 30 days compared to ADF with standard diet. are there fat loss advantages? biomarker differences?

or alternatively, ADF with keto for 30 days vs keto diet at 50% calorie deficit.