IF vs calorie restriction

#1

I’m new to this forum, so if this question is posted before, I appologize for the repetition.
I listened to the podcast episode with Megan Ramos, where she talked about the fasting vs feasting, and how many people’s feasting days were close to fasting in terms of calories consumed, and how this would slow down your metabolism.

But - this is where I am confused. I thought the whole idea of the keto life style is to eat when one is hungry and then eat until you’re full, and that the calories consumed came from your body fat instead of diet.

For example; I do the 16, 18 and omad protocol, and on my omad days, I consume appx. 800 calories from food, and I thought the rest would be taken from my “muffin”. According to my understanding of that Megan Ramos said, that does not hold true. I can understand that people that are note keto-adapted (not burning fat for fuel) will destroy metabolism by heavily calorie restriction (as I do), but also when I’m fat-adapted? I try to eat when I’m hungry and stop when I’m full, but should I be force feeding my self? I believe that eating when not hungry is what brought me to 40 lbs of overweight in the first place.

Please advice (or point me to a post which answers my question).
Thanks.

#2

Following as I have had the same question. All I can guess is that homeostasis is a problem regardless of what WOE you follow (your body gets too used to your approach and adapts accordingly).

(Barbara Greenwood) #3

How often do you do each of these?

The problem AIUI arises with chronic calorie restriction, i.e. every day you take in less than you need. Alternating restriction (or fasting) with periods when you eat plenty avoids the problem. I don’t think this means stuffing yourself beyond the point of comfortable, however.

Megan cautions against OMAD as a weight loss regime, because it can easily become chronic calorie restriction - as you say, 800 calories on those days. If you did that every day, it is highly likely that weight loss would stall while you still have plenty of fat. However, if you mix it up with days of 16/8, your metabolic rate should keep going. As long as you are consuming enough on your 16/8 days, that is.

(jilliangordona) #4

It does seem contradictory for sure. And yes, you shouldn’t shove food in your face if you aren’t hungry… but most bodies will have cycles of hunger that increase and decrease, and riding those waves is where feasting and fast comes in.

I switch it up often, but for example this week I place to do OMAD Monday, fast Tuesday, eat breakfast and lunch only Wednesday, OMAD Thursday and Friday. Then I eat all meals as well as snacks sometimes on weekends.

This schedule compliments with my exercise schedule, with me having rather heavy lifting days on the weekend and Wednesdays.

The real key is changing it up. My big issue now is my body feeling hunger when I get home from work not necessarily because I need food, but because I used to always do OMAD at night. So changing that has helped my body better understand it’s hunger signals.

(Liz ) #5

Hi! I keep asking the same question, too, like here:

and what I came away with was:

  1. don’t eat if you are not hungry (if you know you can trust your signals)

  2. if you are slowing your metabolism there will be signs like feeling crappy, cold, sluggish, etc.

  3. and yes, switch it up. I don’t lose weight if I don’t eat at a caloric deficit but I’m now not afraid to eat a lot of delicious Keto calories on random days especially if I know I’ll be fasting soon.

#6

Thank you so much! I think i’ll continue with what i do. I have not signs of reduced metabolism and i can perform my workouts AS before. Guess i’m okay then, but will keep an eye out for changes.

(Adam Kirby) #7

This is one I think keto peeps overthink from a lifetime of failed high carb dieting. What is exactly is “calorie restriction”? If you are “underreating” from some arbitrary number but you feel fine and not hungry, your body is likely getting any energy deficit from body fat. If so, are you actually restricting calories? you’re just taking some of them from your body fat. I think the problem of undereating when you feel fine is overblown and Ramos et al make people a little too paranoid about eating too little if they’re not hungry.

#8

I have the same question as OP but I think something in your post triggered the answer or at least as I understand it.

When you do CICO restriction your insulin is still high and that blocks your fat from being released to make up the deficiet. So assuming you have 40 lbs of fat to lose, that is 1200 calories a day (30 calories per pound based on Richard’s calculations) you can provide to make up the shortfall, so you are effectively eating 2000 calories a day and theoretically burning 1200 of them from stored fat. On a CICO diet, your insulin would not permit this fat to be used so you would be starving and not able to access the food in the downstairs freezer (Fung analogy).

Still bothers me on some level for the following reasons:

People do lose weight on CICO so they are accessing some stored fat because that is what they are losing. So insulin is not completely blocking fat access in MOST people even if they end up gaining it back Biggest Loser Style

2000 calories a day in the poster’s example (800 plus 1200 stored) or 1200 if a 40 pound overweight person eats nothing but electrolytes and water, is not enough to maintain metabolism so why is there no risk of a slow metabolism on keto or fasting? I do have trouble understanding how your body KNOWS to spare muscles and metabolism on IF and Keto but not on CICO, even with insulin signaling. Also, if Keto does spare you then there really should be no reason to feast and mix it up since Keto is preventing the slowdown, yet we are told to feast before a fast as well as similar comments

(Carpe salata!) #9

The way I think about it is that sugars are the body’s signal that fruit-season is here. Plenty of food, eat up, stay hungry, sit around and pack on the weight(fat stores).

Fat is the signal that hey there’s important hunting to be done. Stay alert, use stored fat to be ready for action, don’t bother getting hungry because food is usually scarce…

Keto diets keep the metabolism in the fat-signal mode.

(A ham loving ham! - VA6KD) #10

Yep! That’s true in people who do not have years or decades of chronic high insulin levels that has caused their body to become “deaf” to the signals that insulin is supposed to provide. One of the aims of keto is reduce insulin to allow the body to regain its insulin sensitivity. It’s a bit like going to a loud concert and developing temporary hearing loss or being subjected to a strong scent and after a while you don’t notice it anymore. Removing the sources for a while allows the body to reset and to return to its normal sensitivity.

A high carb diet, even when calorie restricted will still cause insulin spikes and in people who are insulin resistant, will cause a prolonged high insulin response duration.

(Jim Russell) #11

Dr. Fung explains the difference between IF and calorie restriction here:

https://www.dietdoctor.com/fasting-muscle-mass

Fasting increases growth hormone secretion which decreases protein metabolism. So your muscle mass is preserved. Muscle mass is a big driver of metabolism.

Resting metabolic rate will always go down with weight loss, but under IF, it decreases less than it does under calorie restriction. From the article:

what happens to RMR (Resting Metabolic Rate). During caloric restriction, the number of calories burned by the body at rest goes down by 76 calories per day. During fasting, it only goes down 29 calories per day (not statistically significant from the start of the study). In other words, fasting does not slow your metabolism.

(Adam Kirby) #12

Some of the weight loss is lean body mass, if you can’t mobilize your fat stores. You have to separate the people who restrict calories and are insulin sensitive vs resistant. IS people can drop their cals and lose fat no problem. That’s why eat-less-exercise-more is so pervasive, cuz it is actually a legit strategy for a percentage of the population and you can always find N=1 success for it. Unfortunately IR ppl get a slowed metabolism+muscle wasting in addition to any small fat loss. It completely depends on whether you can mobilize fat on decreased energy intake. For the IR this is the benefit of fasting, vs much poorer results on a low-calorie high-carb diet.

#13

Agreed but let’s face it, no one is more insulin resistant than biggest loser contestants and they do lose even by torturing them

(A ham loving ham! - VA6KD) #14

Granted…those poor buggers! Your body’s focus is to stay alive at almost any cost and given enough of a push it will do some pretty remarkable things to that end.

At least with keto, you can pull back your calorific intake and not (usually) have to deal with the tortuous hunger pangs that straight caloric restriction causes.

#15

This is the answer that so far makes the most sense to me, so thank you!!