The FastDay Forum

Today is my fast day, I haven't felt ravenously hungry. I did eat a bar of chocolate yesterday.

Last week - for my Thursday fast - I was ravenously hungry for the whole day. Prior to that day I had kept down the amount of sugar I ate to a minimum by avoiding cakes and chocolate.

Why was I hungry? My theory was that last Thursday I didn't have any reserves of stored glucose to use up before I switched to starvation mode. I woke up hungry. To stop the hunger today I ate a bar of chocolate yesterday to up my reserves of glucose.

I have cut down the amount of chocolate I eat to 2 100g bars a week, which I eat between each fast. I believe I have not felt hunger because I always have plenty of stored glucose available for fasts.

Could this theory be correct? Have other fasters noticed this?

Is this the cause of emptiness and gnawing hunger on a normal calorie restricted diet?

Is the 5:2 diet successful because depleated reserves are replenished?

I look forward to your replies,
Peter

[carorees]

It sounds plausible to me...but...if you have more stored glycogen won't it taken longer before you start to burn mainly fat?

I have noticed this a bit. I cannot do diets that cut out sugar and carbs to next to nothing because I would be crazy hungry!! However I am needing less and less having done 5:2 for a while. I keep wondering why some fasts I am hungry all day and others not too bad. Is something different happening in your body on the days you are hungry - are you not burning fat, or are you maybe burning more. It must signify something mustn't it?

I've found my hunger on fast days has diminished over time. I now get peckish around each meal time, but then it fades again, as though my body has seen the opportunity for that particular meal isn't going to happen, so wait until next scheduled meal. There is a random "feel hungry all day" fast every now and then, but I haven't been able to pin it on anything - sugary foods, carbs, anything in particularly. Would be really good to keep a full food diary, sure all sorts of patterns could be worked out, but I'm a bit slack.

It sounds plausible to me...but...if you have more stored glycogen won't it taken longer before you start to burn mainly fat?

Thanks for the reply. Good question. I thought there was a limit to the amount of glycogen that could be stored. I was just ensuring that I was full of glycogen.

The theory being that fat burning begins 14-24 hours after the last meal (See About burning fat ..). I then have something to eat at 24 hours - I fast until my 600 cal evening meal. Then some time after I go to sleep and wake up ravenously hungry in the AM and have breakfast fast.

Perhaps I do most of the fat burning whilst I am asleep and hunger is most suppressed.

Does that make sense?

I have noticed this a bit. I cannot do diets that cut out sugar and carbs to next to nothing because I would be crazy hungry!! However I am needing less and less having done 5:2 for a while. I keep wondering why some fasts I am hungry all day and others not too bad. Is something different happening in your body on the days you are hungry - are you not burning fat, or are you maybe burning more. It must signify something mustn't it?

Yes, I agree. The question is perhaps: Is the hunger caused when the body switches from glycogen to fat burning?

You also raise another good point, it maybe that sometimes we get hungry on a fast day and there is no apparent explanation for it.

Thanks for your help.

It's interesting dopeterchina, because you say you wake up ravenous and so do I, but so many people posting on here report that they are not at all hungry when they wake up after a fast. What's that about? I think I have a sugar addiction!

[Betsysgr8]

I notice that my hunger on fast days is much stronger when I haven't had calorie full days preceding fast. Today for instance, I seem much hungrier than my usual Monday fast, I ate fairly light this last weekend, no bread and no booze.

I rarely wake up hungry unless I've had an early carb rich meal the night before, if the meal is late then I'm still a bit full in the morning.

[carorees]

There is a limit to how much glycogen can be stored..I saw a paper claiming it is around 2000 kcal. But you don't use up all your glycogen stores before starting on the fat stores...you burn some fat and some glycogen but the proportion varies depending on your insulin levels, the remaining glycogen reserve and what activity you are doing. Probably insulin levels are highly relevant for people who are overweight/obese. There are several papers about metabolic inflexibility in obesity (inability to increase fat burning). Once you really get into fat burning hunger seems to decrease so it does seem that hunger is related to the body asking "well is there going to be some more carbs soon our do I have to ramp up fat burning?" If no food arrives, fat burning increases and the hunger fades. Waking up hungry may be a sign of high insulin (dawn phenomenon) causing low blood sugar and/or insufficient growth hormone release over night resulting in insufficient fat burning overnight (your body tries to avoid using glycogen when you're resting...it's for active times!).

[Betsysgr8]

Is where the saying "getting your second wind" comes from?

I do feel a bit lethargic while I'm hungry but later in the afternoon when the hunger eases up I have more energy.

Also where other parts of your body can run-off various metabolic compounds converted to ATP (fat and protein etc) your brain needs glucose. So you will be burning fat while you still have some glucose in your system because your body will be desperately conserving that glucose for your brain

You might want to check out how Leptin and Ghrelin effect appetite levels. They are the hormones that researchers claim control hunger and satiety signals in the brain. When a person changes their eating habits, which we all for sure are, it takes time for these hormones to adjust and to reach a new equilibrium. They are triggered by more than just the level of glycogen stores. Even habitual meal times see Ghrelin, the hunger hormone, released by the stomach.

Hmmm...maybe that is why many of us are experiencing diminishing hunger pangs on our fast days? We are messing about with some of the triggers for our appetites.

[carorees]

Lots on leptin in the nerdy section...just search for it! Interesting stuff on circadian rhythm and leptin/ghrelin.