Intermittent fasting vs caloric restriction

(Doing a Mediterranean Keto) #1

Now, it is very trendy to be in favor of intermittent fasting, and even directly fasting in general.

However, at least in keto circles, caloric restriction is not much discussed.

Myself, I am doing a PSMF for second time, and it is clear that it does a lot of good to me. A PSMF is keto, but it is also caloric restriction.

Between the two PSMF, I gained weight, but I continued eating keto. In fact, at my highest weight (when I went to see my doctor again), a blood test showed I was in ketosis yet.

And during that time of increasing weight, I tried all kinds of intermittent fasting: 16h, 23h (OMAD), I did 5-day water fasts …

But for some reason, I do not feel intermittent fasting does any good to me (of course, I could be wrong, since I do not see my inside). And I am very hungry when I restrict the eating time period.

Instead, with caloric restriction, I am eating 4/5 times per day, eating little every time. But I am pretty satisfied, with much less hunger. Except when I wake up in the morning, then I need to eat. I spend about 10/11 hours fasting per night.

And with caloric restriction, and PSMF, I really notice the improvements in myself.

So, my question is: could it be that what really matters is caloric restriction? Some people may accomplish caloric restriction with OMAD, others with PSMF and 4/5 meals per day.

Also, there should be a grey area: eating little at night counts at “not-fasting” in absolute terms, but if you eat little, I would say one is “fasting a little”.

Any ideas?

(Bob M) #2

Oh no, not calorie restriction again…please.

What if by eating higher protein, you’re getting a satiation effect? It’s not the calorie restriction, it’s the satiation.

Anyway, if you find what you perceive to be a benefit, you should do that. No worries.

Meanwhile, I’ve been adding back in intermittent fasting, fasting 36+ hours and eating higher protein and losing the weight I gained during my test of The Croissant Diet.

(Doing a Mediterranean Keto) #3

That is for sure. The high protein in the PSMF is satiating.


This is the classic ‘calories in calories out’ (CICO) argument. From a weight loss perspective, CICO does work. It is simply a logical consequence of restricting energy. This has been demonstrated in continuous calorie restriction (CCR) studies such as the Minnesota Starvation Experiment. And without rehashing the usual arguments for and against this approach, the bottom line is: if energy is not sufficiently restricted, you will not lose weight, i.e. fat/lean body mass.

Regarding your ‘fasting a little’ idea, caloric restriction will upregulate autophagy. Further, if you front load your calories and have a small snack later, you will certainly benefit compared to the opposite approach.


It is your nourishment and nutrients and vits and minerals it gives. It feed the body and doesn’t ever rob the body so that is the whole point of meat and seafood/fish and fowl protein in my eyes :slight_smile: Perfect food choice as nature intended.

---------so to all…WE ALL played these games didn’t we? Still do sometimes LOL but in the end your food with meat protein being key factor here and fresh meat with its fats profile in it is the #1…after that if you add XYZ or ABC everything changes and while does suit so many so well…further crazy we ‘do to ourselves’ thru just reading ‘this should work’ is when we fall more victim to all the insanity dieting whatever out there.

I know everyone who is longer term finding ‘their plans that suits them’ get this but telling others and ramming that point home I don’t think can be just said…you gotta walk the journey :slight_smile: Then you see real truths in food nutrition thru real science and effect and more thru you individaul body.

(Old Baconian) #6

Dr. Jason Fung, nephrologist and fasting guru, asserts that fasting and calorie restriction stimulate quite different reactions from the body. He says that fasting allows the body to simply switch from food intake to stored energy, whereas restricted caloric intake is the signal that tells the body that there’s a famine going on, and it needs to hang on to its resources.

The famine response, he says, is the reason that weight loss from cutting calories is always less than expected, and why people almost always end up weighing even more after they return to a full-calorie diet. The reason is that the metabolism slows down, in order to conserve energy. Fasting, Dr. Fung says, does not trigger this metabolic slow-down, allowing more of the body’s energy reserve (stored fat) to be consumed.

I’m not sure that this is entirely correct, but Dr. Fung is a well-respected advocate of fasting, who has successfully treated a large number of obese patients, so he clearly knows something about fasting.

(Doing a Mediterranean Keto) #7

Of course, I only have n=1, unlike Dr. Fung.

Having said that, my body response to intermittent fasting is as if there was a famine (I am really hungry). Instead, with several small meals, my body adapts better, it is as if my body understood there is less food available, and it accepts that (of course, there is a constant delivery of food, so I will not die of hunger).

(Old Baconian) #8

Yes, everyone is different, and lean people have a harder time fasting than people with a large fat store.


Each to their own. IF is normal to me and the less (but big enough, that’s important) meals I have, the better. Bigger meals satiate me better and longer.
I can’t eat tiny meals, they just make me very hungry right away and I can’t stand that. And if I have 5 meals, I probably still do IF…
So we are the opposite regarding this :slight_smile:
I am against forcing these things. Some people seem to think a long time ketoer must be comfortable with IF or 1-2 meals… I don’t see why would our individual differences go away. Some people is better with smaller meals and some people are hungry in the morning… While I always ate big meals and hated eating before noon, my woe didn’t even matter regarding those things!

I doubt those metabolism changes happen to everyone. Calorie restriction always worked wonderfully for my SO, he slims down to 63kg easily and gaining back goes very many times slower, he is careful, that’s true but he eats a lot. I suspect he is a rare case, though as he lost a lot of fat in a definitely metabolism slowing way, went back to his original, very fatty and carby diet and never got fat again. I never heard another person who could do that. But many people loses a little fat through calorie restriction (and standing hunger. I am not sure what we call calorie restriction here. I guess, intentional calorie restriction. maybe not eating enough to be satiated) without gaining it back for a very long time… Probably not all are super careful all the time but I don’t know, I am not them.

(Michael - When reality fails to meet expectations, the problem is not reality.) #10

IF is caloric restriction, in a sense. It’s a time restriction rather than an overall energy restriction. I think that’s what makes the big difference. You’re still getting the same total energy intake, just timing it differently. And I think the primary objective is to maintain a low insulin level as much as possible during the day. Insulin controls storage and release of fat energy. So the longer it is low the better if you’re trying to lose fat.

I think eating 5 times per day probably keeps insulin high most of the day. So instead, try eating less times per day but more each time. Persistent hunger is your body telling you to eat more - you’re not eating enough overall. As @PaulL puts it - survival mode. In that state, not only is insulin elevated but cortisol and other stress hormones are too.

I eat to macros and to a ‘caloric window’. As long as I eat to my macros and caloric window - I maintain my weight and body comp. These are currently 144-5 pounds and 14-15% BF. I have maintained this for 4+ years. This matches my weight/comp when I was 18 years old. I am currently 76 - so I’ll take it.

With that preamble, and macros consistent - if I eat less than my ‘caloric window’ for several days I will start to lose weight, which I presume is mostly fat but also maybe some lean mass. I don’t have much fat to lose. If I eat more than my ‘caloric window’ for several days I will start to gain weight. Since I am in ketosis, have been consistently for 4 3/4 years, and eat lots of protein I’d guess this is mostly lean mass gain and very little fat gain. Any fat comes/goes in my stomach area, so it’s easy to see.

I usually eat 3x per day. No snacks between. Breakfast every day is my ‘keto coffee’. Some days when my meal break at work is not until mid-late afternoon I will add a coconut/MCT oil and casein ‘pudding’ to my breakfast meal. 3-4 days each week I do my Easy Peasy Overnight IF.

I will also note, although I may be an outlier, that I hardly ever feel hunger. When I do it is only very slight and lasts only a few minutes and goes away. Mornings after my overnight IFs I don’t feel any more hunger than when I don’t do the IF. For a couple months now I have been drinking vinegar before going to bed each night. This has resulted in more hunger signalling, especially after an overnight IF, but still not much and not lasting very long. Just a bit more. So the vinegar is doing something.

Maybe wishful thinking on my part, but I attribute my lack of hunger to metabolic flexibility. Ketosis enables me to metabolize incoming and onboard fuel seamlessly. Whichever is more handily available.


Not true at all, (this) forum is the only keto place (at least that I’m a member of) I’ve seen that constantly disregards calories.

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

Speaking for myself - I don’t disregard calories. I do think it’s necessary to keep in mind that hormones determine what happens to those calories. The ‘in’ and ultimate ‘out’ are determined primarily by hormones not simple arithmetic +/-.

(Old Baconian) #13

Especially if we are insulin-resistant, I’m sure.

I like Eric Westman’s line: “Calories count—but we shouldn’t count them.”

(Butter Withaspoon) #14

If you are always hungry when you wake up you could try to gradually delay the first meal. Your body is stimulated to receive food at the expected daily time so skipping breakfast all the way until noon without preparation is going to trigger a lot of hunger signals.
If you gradually increase your overnight fast by half an hour a day, while taking some salt and water, you may be able to adjust to a longer period of low insulin. Keeping insulin low is what most of us are trying to do to stay healthy (and lose excess fat)