Do you fast everyday?

(Kelly Silverman) #1

Hey guys… I have never gotten a clear answer on if intermittent fasting everyday is actually good? Some said fasting everyday (16:8) will eventually slow down metabolism and wreck havoc on your thyroid.

However, it appears that those on OMAD actually DO fast every single day :thinking:

Is there any Truth to what I just mentioned above? ( 16:8 is not recommended)

Thanks for your experience and input!

(Michael - When reality fails to meet expectations, the problem is not reality.) #2

I don’t know about OMAD and 16/8. I do know that when I was a child, adolescent and young adult in the ancient past before eating low fat high carb and seed oils 24/7 became the vogue, most folks finished supper about 6pm and started breakfast about 7-8am the next morning. So a very large percentage of ordinary folks were doing 12/12 or 14/10 pretty much every day. It was called ‘break fast’ for a reason. I still eat that way and don’t consider it a big deal.

(Bob M) #3

I eat OMAD sometimes but mainly 2MAD, though my 2MAD is probably more than an 8 hour window, especially on the days I exercise in the mornings. On those days, I’m lucky to make it to 10:30 am to have my first meal. I usually have my second meal somewhere from 6pm to 8pm, depending on the day. Was doing 1-2 36 hour fasts per week, but haven’t done a lot of those since the pandemic began.

I’ve been eating this way for a long time. Multiple years. As far as I know, I don’t have a slowed metabolism or a wrecked thyroid. Got a full thyroid workup, and everything seemed OK.


Different people, different results. Many people report good, I lost a ton of muscle and then slowed down my RMR and it took a long time to fix.

(Michael - When reality fails to meet expectations, the problem is not reality.) #5

What exactly were you doing?


Started with the ol’ breakfast skipping, which was fine for a while then started doing OMAD and trying to eat plenty at my one meal or 4hrs. Then got into multi-days which I think was the nail in my metabolic coffin. I didn’t do those all the time but once eating to satiety became a thing for me and not having an appetite (pretty sure because of the fasting) it went down hill fast. Didn’t notice it though because my energy was always pretty descent. I attributed the slower muscle gains to being keto and it wasn’t until I started noticing strength decreases that I got checked out and saw how slow my RMR was.


From visiting farming relatives in Iowa 50 to 60 years ago:

  • Hearty breakfast early (after light early chores, but before field work)
  • Biggest meal at noon, called dinner
  • Supper late, just a small meal

Snacks were called a “lunch”. Usually just something like coffee or tea with a cookie or some kind of pastry. Almond patties were the best!

(Kelly Silverman) #8

But see… I’VE NEVER been a breakfast person… even before starting Keto. Coffee has been my go to for breakfast for over 10 years.

What is RMR?

(Jack Bennett) #9

I don’t think the answer is completely known. My sense is that it’s generally good, and more good than bad, because it keeps your blood levels of insulin down near baseline more often. So it makes you less likely to have or develop hyperinsulinemia. (See, e.g., writings and presentations by Ben Bikman, Jason Fung, and many others). There’s also the potential autophagy factor, which is likely to support health in a variety of ways.

My personal experience is positive as well. I feel fine doing it, it seems to help maintain a healthy weight and body shape for me, so why not?

On the other hand, if I were an extreme performance athlete (I’m not), I bet I would have to be more technical about how I approached fasting.

(Bob M) #10

I’ve done many 4.5-5.5 day fasts, many 3.5 day fasts, many, many 36 hour fasts, and was able to gain muscle mass and strength while doing this. And I’ve been fasting, including skipping breakfast and/or lunch, since June 2016. So 4+ years.

It IS possible to overdo it. If you begin to get really cold, as in you can’t touch your own hand to your body, that’s not good. But all you do is back off, stop longer fasts, and eat more. You feast and fast, feast and fast.

If you find you can’t feast enough, then delay starting fasting.

I find I cannot eat breakfast, unless I’m really hungry. But then what happens is I’ll eat “breakfast” around 9-10am, but I won’t eat again until dinner. On rare occasions, I’ll eat three times in one day. But it’s very rare. If, however, I’ve eaten my first meal and am still hungry, I’ll eat again.

Today, I exercised about 53 minutes, body weight training to failure. Only coffee before. Then I ate “breakfast” at about 10:20 am. It’s 3:47pm, and I’m still not hungry. When I get hungry (or get home and the family is having dinner), I’ll eat.


Resting metabolic rate. Essentially the number we use as our metabolism.

(Michael - When reality fails to meet expectations, the problem is not reality.) #12

I’m posting the following for ref. It’s a stupendous catalog of data! This is the full directory of articles and support files for Fung’s IDM Program. Since it’s directly accessible, I have to presume it is meant to be so:


I have some exceptional (and not optimal) days when I have a very huge eating window, even more than 8 hours but IF is natural for me, yes. I do that since a decade or more, I did it way before I learned that it’s a thing with a name.
Nope, it does nothing bad to my metabolism. It’s still quicker than average for people with my stats and it doesn’t matter if I do OMAD or not though I never tried long term OMAD.
The one almost fixed thing is that I don’t eat before 3-4pm. I am simply way too satiated until then, no matter why woe. I can’t do high-carb anymore but I had carby OMAD days, they are the easiest as I can eat a ton using carbs too, OMAD is hardest on carnivore but I never do OMAD every day anyway. I still like small eating windows, 8 hours is way too big for me. Today I ate after 5pm, I wasn’t really hungry but it sounded a nice idea, I love food and need it at some point anyway. So I obviously do IF except when I eat after midnight but I don’t like that.

As far as I know, metabolism slows down if one starves (eats so low-calorie that the body can’t handle it well. the size of fat reserves matter) and I never do that. I always had bigger meals and my body is way too good at demanding its calories so if my first meal is too tiny, I will eat later. I don’t force OMAD or even IF… If I need food, I eat.

(Michael - When reality fails to meet expectations, the problem is not reality.) #14


This includes the audio and transcript.

(Eric - The patient needs to be patient!) #15

I do TMAD 16/8 mostly or 17/7. One to two days a week I’ll do 3MAD but even on those breakfast might be at 9 or 10 am. I do this for social reasons with family and to keep my body guessing. I’m visually losing fat and gaining lean muscle mass. I get 120 to 180 g protein a day. I exercise almost every day. Resistance training Lower Upper split 2/week so that is 4 days. I sprint 3 days a week. Never on lower body days bit can on upper days. I average walking 5.5 miles a day but weekends is light and some weekdays I get in 8+ miles.


Well ain’t that some ■■■■! Funny how the same guys advise that screwed mine in the first place is now telling people how to fix it!

(Bob M) #18

I think they always knew it was possible to overdo fasting. They have hundreds/thousands of patients and must have seen it.

I admit that this is not mentioned enough in Dr. Fung’s materials.

(Jack Bennett) #19

Fung and Steve Phinney seem to differ on the impact of fasting on LBM.

I think Phinney came up with an estimate of -0.25 lb per day. If true, that means a week long fast would make you lose almost 2 lb of muscle!

(Bob M) #20

I believe Fung more than Phinney for this. I have done many (as in MANY) 4.5-5.5 days fasts, while gaining muscle. This is therefore not true in my case.

Now, I don’t have DEXA scans to prove this, mainly because these cost $150/each where I live. Otherwise, I would get them more often.

I also was lifting weights during that period. Perhaps people who don’t lift weights would experience a muscle loss?

(Bacon by any other name would taste just as great.) #21

Phinney is, I believe, relying on the work of George Cahill, which as far as I know, has not been refuted. The loss of lean mass is highest during the first few days and tapers off subsequently. BTW, if autophagy is a factor in this, the loss of a certain amount of lean mass may not be a problem.

My sister told me yesterday that there’s a place with a half-off sale going on. You want me to PM you the info?