The FastDay Forum

I read up on eating once a day over the weekend and I have started playing around with it this week. I am fasting my regular Mondays and Thursdays. On Tuesday and Wednesday I had huge meals around 5pm. Seeing that my TDEE is around 2650 I want to eat between 2500-3000kcal on feed days.

I would like to know whether anyone has eaten like this over a longer period of time and what your experiences are. I would appreciate any input.

My first impressions are positive. I like to eat big meals. Today I was full until 3pm from yesterday's meal, giving me two hours to think about the double cheeseburgers I was going to devour. It is now 2:30am and I have not been hungry at all during the evening. I may however tweak it a little to give me a 4 hour window for eating. Eating 2500+ kcal in one go is a lot of food. I would rather make it 1800 kcal or so for dinner, a couple of hours break and then more food or dessert.

[Tracieknits]

Double cheeseburgers - as in more than 1?

Well I'd say it's not just when you eat that matters, it's what you eat. I don't know that anyone is going to give you the thumbs up on a meal that consists of two double cheeseburgers. It's not just the calories you ingest that affects your overall health, or the time you eat them. The quality does matter too!

I was not looking for thumbs up on the choice of today's dinner, but while we are at it we can talk about that.

The burgers consisted of bread, cheese, onions fried in butter, tomatoes and a tad BBQ sauce. The burgers were made with 50/50 minced beef/pork, cream and eggs. The only objection I have with that is the bread. I am mindful with carbs but one of the perks with 5:2 is that I don't need to be as restrictive with carbs. That said, I was too full to finish both burgers and opted to finish the beef and toppings and leave half a bun in the plate.

All in all I ate 60gr of carbs from the buns and perhaps 15gr of carbs from the BBQ sauce. This comes to roughly 60% of calories from fat, 20% from protein and carbs respectively. Not too shabby at all. A bit heavy on the protein, but the day before I did not at as much protein, so seems fair enough.

Beef, pork, eggs, cream, butter, cheese, tomatoes, onions are high quality foods.

[Tracieknits]

Yeah, I don't think we're going to see eye to eye on this one. That sounds like a heart attack to me.

How many calories is that for the single big meal of the day? (LOL ETA: I need to read more-closely. You said 2500 cal for a single meal, which is probably too much for anything sustainable, especially if you train your stomach to not feel full with smaller meals and need big meals to feel full.)

I think as long as you keep around your TDEE the rest of the week and this big meal doesn't go much beyond 1000-1200 calories (though I'm wondering if it might) you'll probably be able to sustain weight loss for a while at least. I wouldn't be surprised if it works well for a while and once you get about half way to your goal weight your weight loss rate will slow down considerably.

That is, unless you're tricking your body with some ketosis thing -- are you high-fat, high-protein, low carb the rest of the week as well?

That all said: do a search on "16:8" and you'll get a feel for what a lot of people are trying as a variant of 5:2. You limit your food intake to an 8 hour window each day. If you shorten that window to 6 hours or 4 hours it's basically the same story, but the smaller the window the better it seems to work.

Yeah, I don't think we're going to see eye to eye on this one. That sounds like a heart attack to me.

It is a myth that a high fat diet increases the risk for cardiovascular disease. My dinner consisted of high quality, natural foods with a tad of crap in the BBQ sauce but hey... It was good.

How many calories is that for the single big meal of the day? (LOL ETA: I need to read more-closely. You said 2500 cal for a single meal, which is probably too much for anything sustainable, especially if you train your stomach to not feel full with smaller meals and need big meals to feel full.)

I think as long as you keep around your TDEE the rest of the week and this big meal doesn't go much beyond 1000-1200 calories (though I'm wondering if it might) you'll probably be able to sustain weight loss for a while at least. I wouldn't be surprised if it works well for a while and once you get about half way to your goal weight your weight loss rate will slow down considerably.

That is, unless you're tricking your body with some ketosis thing -- are you high-fat, high-protein, low carb the rest of the week as well?

I was in ketosis for 9 months, so I used to be a real low carber. Since I switched to 5:2 I am consuming more carbs, but I am mindful. With mindful I mean that instead of eating fries or other kind of potatoes with the burger, I'd rather have a second burger.

In regards to your TDEE comment, my current TDEE is 2650. Since I only eat once a day now, I really need to get close to that on feed days. I fast two days a week and my avg calorie intake per day usually averages around 2200 per day, fast days included. If my one meal was around 1000-1200 I don't think that would be enough food to keep me full for a whole day and it may be harmful to my metabolism to have such a huge calorie deficit. Did I miss anything in your reasoning?

That all said: do a search on "16:8" and you'll get a feel for what a lot of people are trying as a variant of 5:2. You limit your food intake to an 8 hour window each day. If you shorten that window to 6 hours or 4 hours it's basically the same story, but the smaller the window the better it seems to work.

Thanks, Bruce. I have read quite a bit about 16:8 and stuck to that regimen quite a few feed days. I was just looking to kick it up a notch further to see how I like it. Like I said, I am leaning towards a 4 hour window at the moment. The studies I have read don't show a great difference in health markers etc when eating once or three times or six times a day. The way I look at the number of meals per day is mainly what works best for the individual. I am self experimenting a bit.

I fast two days a week and my avg calorie intake per day usually averages around 2200 per day, fast days included. If my one meal was around 1000-1200 I don't think that would be enough food to keep me full for a whole day and it may be harmful to my metabolism to have such a huge calorie deficit. Did I miss anything in your reasoning?

Oh my bad -- I thought that the one 1800-2500 calorie meal in a day was your fast day. I didn't realize you were doing this on two of your feed days. For some reason I can't read everything and my mind is skipping over important things today!

Yes -- as long as your average calories per day over the course of the week is about 500 less than your TDEE you should be good to go weight loss wise. Just know that you'll have to dial it back quite a bit once you lose the weight.

I'm still wondering if the very-large meal might teach your stomach the wrong ideas about what "full" needs to feel like. Personally, I find the best part of 5:2 being hunger management and learning to feel what "hungry" really feels like and then being able to contrast that with "satisfied" rather than going all the way to "full."

If it works, though, more power to you! Best thing about this WOE is that there's usually no harm in trying something. If it doesn't work, try something else.

I fast two days a week and my avg calorie intake per day usually averages around 2200 per day, fast days included. If my one meal was around 1000-1200 I don't think that would be enough food to keep me full for a whole day and it may be harmful to my metabolism to have such a huge calorie deficit. Did I miss anything in your reasoning?

Oh my bad -- I thought that the one 1800-2500 calorie meal in a day was your fast day. I didn't realize you were doing this on two of your feed days.

Yes -- as long as your average calories per day over the course of the week is about 500 less than your TDEE you should be good to go weight loss wise. Just know that you'll have to dial it back quite a bit once you lose the weight.

I'm still wondering if the very-large meal might teach your stomach the wrong ideas about what "full" needs to feel like. Personally, I find the best part of 5:2 being hunger management and learning to feel what "hungry" really feels like and then being able to contrast that with "satisfied" rather than going all the way to "full."

If it works, though, more power to you! Best thing about this WOE is that there's usually no harm in trying something. If it doesn't work, try something else.

Ah, yes... I was talking about feed days. Fast days I stick to eggs and tuna salad mainly, 500 kcals or less. And sure, it may not be optimal with these huge meals. Then again, it may be. my thinking is that even if my stomach is stretched from eating such large meals, if I stick to one meal per day it doesn't really matter. But we will see. We will also see whether I like this WOE over a longer period.

I have no idea what the benefit is by eating this way, but as far as I know there is no law against it.

You would have to ask one of the scientists around here, but you may find you don't lose as much fat (weight) as you might want to. Most of the carbs you eat will end up deposited as fat because of the huge spike in blood sugar caused by that many calories hitting the system at the same time. Unless you do a lot of exercise after you eat, there is nowhere else for all of those calories to go, and the body will not allow them to just stay there until you need them.

Simcoe: Do you have any sources supporting the claim that eating fewer meals will cause more fat to be stored? My reading so far does not indicate this.

Also, I don't plan on exercising after consuming such a meal. That may look funny and probably feel awful.

Isn't part of Brad Pilon's system a 4 hour eating window? You might want to check out what he says.

Simcoe: Do you have any sources supporting the claim that eating fewer meals will cause more fat to be stored? My reading so far does not indicate this.

Also, I don't plan on exercising after consuming such a meal. That may look funny and probably feel awful.

The question is not 'eating fewer meals' - it is eating 'one massive meal'. If you have looked around this site on what to eat on your fast days, most recommend fat/protein and maybe complex carbs. The reason is basic, but it is not a simple issue. Think of 'fast acting' pills and 'time release' pills. A carb pill is fast acting. A fat/protein pill is time release. If you eat a carb pill on a fast day, it will be digested quickly (quickly converted to blood sugar), used and you will be hungry again. If you eat a fat pill, it will be digested slowly and the blood sugar level will remain constant for a longer period of time. You will not get as hungry as quickly.

The question is what happens if you eat a couple of handfuls of fast acting pills all at once? They are all digested quickly, blood sugar levels spike and the body must deal with all of the blood sugar it does not need. It does that simply by converting the sugar to fat.

This is why current research has identified the 'low fat' (high carb) diet as a leading cause of the 'obesity epidemic'. You eat a lot of carbs, they are quickly digested and converted to blood sugar, the body can't use it all, it is deposited as fat, and you are hungry again and need to eat - more carbs.

Sorry for the non-scientific language, but I'm not a scientist. This video might help, but it is long (and dry).
the-5-2-lab-f10/topic6811.html

Anyway, by eating a massive amount of food all at once, your blood sugar will spike because of the carbs, and be added to by the slower digesting fat/protein, and the body will have to do something with all of that blood sugar. It converts it to fat. Whether and when that fat will be burned depends on the rest of your diet, exercise and amount of calorie restriction.

But I go back to why? Why eat this way? What are the benefits you have read about in a book? What is your goal? Like I said, I really don't care how you eat, but I am interested in learning if there is a real, research driven reason for eating this way.