Intermittent fasting - meal size

(Diana) #1

So I just re-read Jason Fungs advice and guidance on IF and I’m wondering if I’ve been doing it all wrong. It appears that when you do OMAD for example and you break the fast you should eat a meal of normal or just slightly larger size…I’ve been under the impression that I should try and consume relatively the same amount of calories (for example I usually eat close to 1200) so I should aim to eat this in my one meal.

Does the same rule apply if you don’t have a lot of fat to lose (ie normal sized meal for post fast) or will this impact the bmr?


There are two things. What feels comfortable and what your energy need is. And for the change in meal size it’s important how many meals you had before, if you ate according to your actual goals or what.
But I don’t know why my old meal sizes would matter. Unless I have problems with eating much more at once… But if one isn’t ready to eat properly, the solution isn’t eating the usual size of meal even if it’s 4-500 kcal… Starvation isn’t good, we need our protein and other essential nutrients too… And I for one can’t undereat for long. I don’t want it either, most definitely and my body whole-heartedly agree.

So I don’t think there should be a strong correlation between old and new mealsizes, it makes zero sense to me especially that many of us don’t have the same mealsize when we eat multiple times a day… My first meal almost always the biggest. But we should eat according to our goals anyway except when it’s not comfortably doable… But than OMAD may not be our way yet, again. I am not a forceful one and I can’t eat X calories because I decided so. I eat as much as I feel right. Food choices and timing can help changing my calories but there are limits.

1200 kcal is such a tiny amount that I surely wouldn’t go below…

To me, it’s not so important how many times I eat. I have a daily… vague goal but I eat whatever I feel like and tweak my woe if it’s not right. OMAD is just a simple way to distribute my meals, it’s not particularly special, I should eat the same, just in one sitting. Maybe it’s different for others, fine, each to their own, but mine makes sense to me and I can’t get away with small OMAD meals, no matter if I have much or little to lose. And I can’t condone eating tiny meals anyway, it’s starvation… Yeah, I would think it may easily harm my metabolism. Starvation works that way as far as I know.

(Diana) #3

I guess the second part of my question is how do you safely go back to twice daily eating without regaining weight. I feel like whenever I try I gain and anticipate it’s bc of meal size/calories. Or is it bc more frequently eating causes multiple insulin spikes and this will always make you gain more weight even if you eat the same amounts? Like if you eat 1200 calories in 1 sitting vs eating 1200 across 2 meals will you gain weight since you’re eating more frequently even though calories are the same?

(Bob M) #4

Good questions. If you ate the same amount, split over two meals instead of one, wouldn’t you have half the insulin in each? Without an insulin meter, it’s probably impossible to tell. Though perhaps one big insulin hit is better than two smaller ones.

I have tried a modified fast, where you’re supposed to eat less (typically, substantially less) at one meal. I can NEVER do that. I end up trying to get all my daily calories in one meal.

The only time I can eat OMAD is if I have unrestricted eating, eat a meal later in the day (so I don’t get hungry again), or eat a TON of saturated fat (which makes me satiated for a really long time).

(Diana) #5

Okay I feel really silly for asking this but Here goes…does the insulin amount/impact vary based on quantity of food eaten?

So for example, let’s take 1 lb of steak. If consumed in 1 sitting vs 2 meals will insulin impact be the same and thus fat burning potential the same? Sorry for being naive about this but I thought this is why fasting was recommended was to reduce number of insulin spikes which allows the body to burn more fat.


Whatever your caloric needs are I’d make sure I ate it when I did eat. I’m not really pro-fasting these days but spend a lot of time doing IF and OMAD, biggest regret I have during those was eating to satiety. I slowed by RMR down pretty bad. If you’re only eating 1200/day that shouldn’t be hard to do with a big meal, I’d make sure you get it in.

(Diana) #7

To make sure I understand. You’re saying when you did IF you ate to satiety which ended up being fewer calories than what you truly needed so this damaged your Rmr. How did you fix the rmr so that you could resume eating more frequently?

(Bob M) #8

Fasting is recommended to reduce insulin values, repair the liver and pancreas.

As for whether eating two meals versus one is better…it’s really tough to say. I know of only ONE study to look at this, and its results weren’t that convincing.


Correct. Figured if I needed food my body would make me hungry, it didn’t. It’s taken me a little over a year of reverse dieting and putting on a lot more muscle to get my metabolism back up. When I hit the lowest point and couldn’t loose without eating near nothing my RMR was measured at 1700, I’m now still loosing slowly in the 2500cal range. Hopefully I can get it better than that. To me, nothings worse than not being able to eat. I love food too much.

(Diana) #10

So I’m a little off topic of my initial question but my fear is if I increase eating frequency I will gain weight. And this could be because of my Rmr. How did you safely do this without weight regain? From what I’ve read you should increase calories by 100 each week?


Ya, that’s what I did, 100cal increases per week. Sometimes some gain will happen, really no way around it. You can always roll back 50 if you need to. Usually once a week I’d just eat what I wanted calorie wise. Typically ended around 3000 or so. I really think the bursts helped. Sucks having to do it but it does work. Obviously upping physical activity will help you eat more as well.


Would you mind sharing it?


I don’t know what happen to the average body at that point… But as the calorie intake may change too (okay, many people actually able to eat a specific amount of food, it’s still surreal and unnatural to me as I am very different), there are possibilities. And people are different.
In general, I doubt it matters much. Eat the same proper amount of food and expect the same weight wise. Maybe it adds some extra for some people just like keto has this effect on some (allegedly very many). I never experienced anything like this so figure it out for yourself.
I honestly find it’s super unlucky, even very tragic if someone is able to gain eating 1200 kcal. I would expect fat-loss with a good pace, no matter the woe and the food distribution. Even if some people really need this little to lose fat, GAINING with this? Very unrealistic for most people.
(My body would scream bloody murder and starvation even on carnivore where I eat the least. But my energy need isn’t the smallest but having 1200 kcal for maintenance… and above maintenance… That’s serious and hopefully quite rare.)

For a very long time I ate about the same amount of calories for a long time, with fat-loss in the beginning so I could figure out the responses of my body. Just reaching maintenance calories, I stalled. I went keto, did 3, 2, 1 meals, nothing happened if I didn’t manage to eat less at the same time. Maybe it’s just me but I doubt frequency makes a significant change in most cases. It may matter a little but much? I doubt it. And 1200 kcal is so very tiny that I surely wouldn’t worry about gain.

But I understand the curiosity in general, I would gladly read about what the body does in this situation myself. I just can’t apply it to my own case as my body is super stubborn and don’t care about such things, it seems.

(Bob M) #14

Here is the review of it:

The study, which sadly is behind a paywall:

(Bob M) #15

I think the title of the Diet Doctor article is slightly misleading. They should say something like “Is a shorter eating window better than a longer one?”.

When I first saw the headline, I thought it was comparing doing more fasting (say 36 hours, 3 days/week) versus less fasting (36 hours, 1 day/week).


Thanks. Sadly I would have liked to see a 2 hour or less window in people with very low adipose tissue and not metabolic syndrome.

Compressed version.
compressed.pdf (460.5 KB)


Nor surprising, 18 and 20 hour fasts are similar. Similar length fast and in my case, probably the same amount of meals (and possibly stress due to the unnatural size of eating window. I did 19/5 a lot but I can’t do 18/6 or 20/4 for long).
16/8 and 23/1 is probably way more different :wink:

(Bob M) #18

I think many of us would love to see different studies. I THINK eating even shorter could help, but that’s also clouded by when you eat (too late might not be good).

And I’d love to see some studies of extensive fasting regimes. As in every other day not eating. What happens here, particularly to basal metabolic rate?


I used to do Omad with a one hour window but it was hard to eat more a 300-400 calories in one meal. I do better TMAD and can eat more fat.