Intermittent fasting

[Jebus]

I have met a lot of people who regularly skip meals or a full day of eating. They say it makes them lose weight and makes them feel better. Obviously it will make one lose weight as one takes in fewer calories. However, does it make a difference if one eats 20 percent fewer meals or if one eats all meals but with 20% less food?

I have two concerns before giving this a try.

1. Is it not catabolic? (I don't want to look like a pencil neck.)
2. Is it not a problem that one will not meet one's daily nutritional needs during the fasting?

[brimstoneSalad]

#1 I don't know. I wouldn't do it without a few good examples to follow.

#2 Your body has a cycling pool of nutrients, and you'll be absorbing them for a while after you eat. As long as you don't fast for more than 24 hours it's probably fine.
The larger problem may be the limits your body has on how much of certain nutrients it can absorb at a time, so you might have to get more of them.
But if you're doing something like on days and off days, that may not be as bad since you have a whole day to absorb them.
I just don't think there's enough research on this to know how your body responds to it.

Notice the paucity of the research section here:
https://en.wikipedia.org/wiki/Intermittent_fasting#Research

I don't think there's enough evidence to say if it's more or less effective relative to the simple restriction of calories. Some people find it easier to follow, though, and that's a huge benefit.

[Take5]

I've been IFing for over five years, now. Along with becoming vegan (and marrying my wife, obviously! ), I rate this as one of the best things I've ever done. I began with the 5:2 method, lost 24lbs, then moved onto a 1 day a week 24 hour fast. I also throw in several 16:8s during the week - basically not eating breakfast. Since not having breakfast has become my routine, a 24hr fast is just missing out lunch one day per week.

I'm 5' 7" - I went from 152lbs to 128lbs, and I've been steady around there for 5 years, where previously I struggled to maintain a steady weight. But IF is a lifestyle - any weight loss is just a side effect.

I now have more energy than I know what to do with - I bounce across the lounge to open the curtains in the morning, I skip down the path to the garage, I buzz around town. I'd jog everywhere (I find walking too slow!) if my knees would allow it. Honestly, I feel so alive!

There is a lot of science out there. I began fasting when I read that it helps against prostate cancer, but there are many other benefits:

http://bigthink.com/21st-century-spirituality/is-fasting-the-key-to-a-healthy-diet

The article mentions Vardy, Mattson, Longo - all respected scientists in this field, with their own individual takes on the subject. I feel that we've developed to deal with famine and feast - our natural state is 'unfed', I feel, and food is a necessary intrusion. I know that if I don't eat, I don't feel hungry - if I eat, the body says, "Aha, there's food around, I'll stimulate the appetite so that I can lay down fat for the upcoming famine." So a couple of hours after eating breakfast, I'm reaching for a packet of biscuits, or whatever.

A WFPB diet is brilliant for health - so is intermittent fasting. Put the two together, and add some bodyweight exercises = optimum health.

I'll post a couple more links to the science when I get a chance.

[Jebus]

#2 Your body has a cycling pool of nutrients, and you'll be absorbing them for a while after you eat. As long as you don't fast for more than 24 hours it's probably fine.

Wouldn't that just be postponing the problem to the next 24 hour period (the period right after one breaks the fast)?

I now have more energy than I know what to do with - I bounce across the lounge to open the curtains in the morning, I skip down the path to the garage, I buzz around town. I'd jog everywhere (I find walking too slow!) if my knees would allow it. Honestly, I feel so alive!

That's great and I'm glad that you found something that worked for you. I'm not surprised you lost weight as your total calorie intake was reduced. However, are you sure you can directly attribute your feeling of well being to the IF? There are many ways one can lose weight and feeling great after the weight loss is not unexpected. Couldn't your higher energy level also be attributed to your plant based diet and your regular exercise routine?

There is a lot of science out there. I began fasting when I read that it helps against prostate cancer

Prostate cancer is probably extremely low among vegans. I doubt these research results have any benefit to vegans.

My motivation to try this is not really weight loss, but I'm all for it if it will make me live longer, look better and feel better.

[brimstoneSalad]

#2 Your body has a cycling pool of nutrients, and you'll be absorbing them for a while after you eat. As long as you don't fast for more than 24 hours it's probably fine.

Wouldn't that just be postponing the problem to the next 24 hour period (the period right after one breaks the fast)?

I'm not sure what you mean. After 24 hours you can start to restore the depleted pool by eating again.

[Jebus]

I'm not sure what you mean. After 24 hours you can start to restore the depleted pool by eating again.

I thought you meant it takes a while before the body starts absorbing them. Now I am even more confused. How long does the absorption period last and how does that relate to recommended daily nutrient intake? What would the benefit be to eating every day rather than every second day (other than avoiding hunger discomfort)?

[brimstoneSalad]

I thought you meant it takes a while before the body starts absorbing them. Now I am even more confused.

Your body is absorbing while you're digesting. You're still digesting after your last meal until shortly before your last poop. Much of it happens right away, in and after your stomach, but many things pass down to your small intestine and there are a few things that linger after that.
Here's an overly complex outline, probably with more than you ever wanted to know (or need to):
https://en.wikipedia.org/wiki/Human_digestive_system
It enters your blood, and that's where the nutrient pool is. Vitamins, minerals, and amino and fatty acids.

What would the benefit be to eating every day rather than every second day (other than avoiding hunger discomfort)?

It's not clear how much of a benefit that is. You have limits to how much you can digest and absorb at a time, partially due to the limit of enzyme activity on breaking things down, partially mechanically, partially the chemical mechanisms of absorption themselves, but those may be upregulated, and the limit may not be tight enough to harm you if you are still eating all day every other day.
I'm more concerned with the practice of eating a single huge meal in a day v.s. the practice of eating every other day.

[Take5]

are you sure you can directly attribute your feeling of well being to the IF? There are many ways one can lose weight and feeling great after the weight loss is not unexpected. Couldn't your higher energy level also be attributed to your plant based diet and your regular exercise routine?

Nope! I was WFPB 9 years before I began IFing, and it was a couple more years before I took up serious exercise. I first noticed my energy increase a couple of months after I started 5:2. I came out of a supermarket carrying two heavy shopping bags - and found myself skipping towards my car. I went through a period of almost euphoria at that stage, but that soon calmed down to an enhanced feeling of well-being.

Have a look at this BBC Horizon programme:

http://www.bbc.co.uk/iplayer/episode/b01lxyzc/horizon-20122013-3-eat-fast-and-live-longer

I'd say give it a go - what have you got to lose?

[Jebus]

I first noticed my energy increase a couple of months after I started 5:2

Please explain how you do the 5:2. Is it two full days in a row without food?

[Take5]

No, the recommendation is a quarter of one's calories on two days a week (generally separate, but they don't have to be). I started 6 months before the above Horizon programme was aired, and I thought 25% of daily calories was a bit extreme, so I started with cutting out half of a day's intake twice a week. So on a Monday I'd halve each meal, and have the other half on Wednesday. Without me even trying to lose weight, the lbs started to come off. I lost 8lbs between Feb and August. After the programme, I went down to 25% of the cals and lost a further 16lbs before I hit what I consider to be my ideal weight.

So men are allowed 600cals, and women 500 - and you can pack a lot of food into 600 cals! I've always said that vegans have an advantage with this WOL (Way Of Life), because we know the value of vegetables. When I was at my peak I could make a veg curry for 100 cals - and still had to leave some. I was never deprived on the 5:2, I was always satisfied after a meal.

Michael Greger has been saying for a while that he's studying IF and will come out with a load of videos on the subject when he's ready. Coincidentally, on his monthly YouTube Q&A, yesterday:

https://www.youtube.com/watch?v=32GbUuL1oe0

...he said he's about to have a lengthy Webinar on fasting - so keep an eye out for that.