Oops! Yes-restricted. I probably should have said super restricted because it's really that crazy choco chip cookie dough one that I would run a mile for.

You just asked a pretty complicated question believe it or not. If you don't want to read a long answer I will just say specifically that your metabolism isn't going to slow down because you didn't eat for many hours after running.

Longer response? The answer to this any many other similar questions like it is that it depends. It depends on what and when you ate before exercise, your goals towards the exercise, what kind of exercise you're doing along with the duration and intensity of said exercise. In most cases for the average citizen just exercising for health it makes no significant difference one way or the other.

Some background ... the idea that one has to eat immediately after exercise (or within an hour) comes from studies that were done on fasted subjects who were weight training. The results are pretty clear if you're trying to build muscle and you work out after fasting you really need to eat ASAP after exercise to maximize your results. This is because exercise puts your body into a catabolic state (but it really depends quite a bit on the intensity and duration of the exercise) and when you're in a fasted state you're already catabolic. Eating puts it into an anabolic state.

To specifically answer your question, if you run in a fasted state not eating after running won't slow down your metabolism (BMR) but you might (probably) become quite lethargic if you wait too long to eat and if you're lethargic you're going to be moving less and therefore burning fewer calories.

In the context of the IP diet I'd say people should really take it easy and avoid long intense exercise because you're on such a restrictive diet. Something like crossfit for example would be a terrible idea in my opinion. IP says to have an additional packet and I agree you will want to eat back your exercise calories because the restrictive diet impairs recovery significantly which can lead to injury or worse. Just let the dietary deficit do the work for fat loss. As far as eating within an hour afterwords if you ate 2-3 hours before hand it doesn't really matter because of how long it takes a mean to fully digest but eating within 1-2 hours is probably a good idea as a good rule of thumb.

I'm not sure if this answered your question or not.

Ok...now I have a silly question to ask. Do you think that this diet slows down your metabolism? This is my second attempt at IP...and I'm having a difficult time restarting.

A friend at work is trying this a 3rd time...she did good for awhile in maintenance, then stress hit. She is starting this weekend, but is worried that the weight won't come off again. Do you think it's possible for her to lose again? As far as I know she never cheated the first 2 times.

We are both frustrated but determined. Needless to say we will have a buddy system!!

Age, hormones, lack of exercise, dehydration...those things can slow your metabolism. Not the diet I am 4 weeks into a reboot and losing again just fine! Restarting can be tough because it's harder MENTALLY to get back on the IP wagon - we deprived ourselves the first time, going back to P1 and having to give up favorite foods all over again is HARD. The program works - if it didn't we wouldn't be back here after regaining, we'd move on to some other program. You both will do great!

Thanks for the answer, JohnP and scorbett.

JohnP, your long answer was what I was looking for and Scorbett's answer was also really relevant. I'm not doing IP specifically but just had a Dexa scan and looking to lower my BF% to under 20% (22% atm) so am considering qsomething like a PSMF but wondering whether it will do me more harm than good (I've got a good amt of muscle which I don't want to lose).

My main purpose is to run faster and while I've read books on sports nutrition, I wasn't really sure whether eating immediately after was necessary (sometimes I just don't have time to make a proper meal) and if necessary, how much was necessary.

Thanks again for this.

Actually, VLC diets are well-known for slowing metabolism. This is one of the reasons WL slows over time. The other reason is because we're smaller and require less energy. Go find the research. It's pretty prevalent. A source I can point you to quickly is Chris Kesser who has written several articles on the subject. Here is one http://chriskresser.com/is-a-low-car...ng-your-health

For most people, the metabolism rebounds pretty quickly once a maintenance amount calories are eaten again. Others, like me, may develop a more sluggish thyroid, which takes longer to recover.

Does this info mean you can't lose weight? Nope. It just means it is not always as fast as we'd like it to be. But slow and steady wins the race.

So, if you start hitting a major slow down when you still have 20+ lbs to lose, how do you get your metabolism up? since cutting more calories is almost impossible and probably not a good idea.

do you start weight lifting? taking supplements?

You keep losing weight. Just slower.
We already take supplements.
The Ideal Protein diet works and we can't decide the pace of success.

Weight lifting would actually cause a stall or perhaps a gain on the scale. This is due to several factors, which have been discussed on this forum numerous times. However, it will not cause a gain of fat. Studies have shown that people with the most maintenance success engage in strength training activities. This could be weight lifting, but not necessarily. There are a lot of body-weight activities that increase strength.

You have three goals. Get to under 20% BF, keep your muscle, and run faster.

In this context a PSMF is not a good idea if you want to pursue all three goals at the same time. Improving your endurance involves protein synthesis so you will need to lose weight slowly. Losing slowly also helps retain your muscle.

If you do decide on a PSMF I would not go longer than 2-3 weeks at most before taking a break.

You may already know this but for most women getting to 20% or below is challenging but maintaining there is often impossible. A lot of this is genetic so YMMV.

Thanks John. Good advice.

I'm leaning more towards not doing it as I want to put in as many miles as I can for an ultra early next year and doing it would mean reducing training intensity. (Thought of RFL, looked into IP as well).

Yeah, I see your point about low BF. I think I'll eat just a little less carbs for the next 6 months and see where that gets me. Will do a follow up Dexa then!

Interesting reading and great info on this thread to be sure - thanks everyone!

You might try adding a couple of hard boiled egg whites when the mid-morning hungries hit. I always seemed to hit them about 9 a.m. (I'm an early riser too and am in the office usually before 7 a.m.) and they really helped.