Archive for October, 2013

Exercise and intermittent fasting Part 2

Well… Dr Michael Mosley, the main proponent of the 5:2 diet may be a medical doctor but from what I’ve just been through he’s no exercise scientist that’s for sure.  I note that s0me of his other ideas about exercise are a little misguided and indicate he’s never really had a dip at some physical hard work.  For example, he doesn’t believe exercise promotes production of endorphins siting of the lack of research in the area.

” The idea that working up a sweat will put give you a rush of endorphins and put pep in your step is rubbish. This is based on a few studies on a few people,” he says.

As with many concepts, true understanding comes with regular research on a concept and a trend amongst that research in a particular direction.  But some things go without saying and don’t need research for them to be fact. Anyone who does regular intense exercise actually knows first hand the endorphin state after exercise regardless of the lack of research.  So that’s a bit of a hit for his credibility from the start, but the idea of intermittent fasting is not his idea to start with, so I gave it a go.

So… can you exercise on this type of diet?  The short answer is no.  Not if you are exercising at the intensity required to encourage the body into repair mode (mostly anaerobic exercise at the edge of your performance levels for the appropriate amount of time).  The training I do both personally and with my PT clients is specifically of this intensity.  Superset weight training – six exercises in three pairs, 3 sets of 8 so that the eighth rep of the third set is all you can do, fast concentric, slow eccentric, short recovery between pairs, immediately followed by some high intensity interval training, for example 6 x 60 second runs at 7-8/10 effort with a 60 second recovery – – for me running – for most of my clients on a spin bike.  You need some fuel for this.

Perhaps if you were more sedentary and enjoyed a daily walk around the block you could probably do it, but here’s what happened to me:

My two ‘fasting’ days were Tuesday and Thursday.  On the Tuesdays I had no problem exercising despite not eating.  One of the advantages that I perhaps have is that will power isn’t really an issue.  I’m an ‘eat for fuel’ type of person mostly so I don’t eat specifically for taste or recreation.  If I’m supposed to fast I can do that without too much trouble.  The hunger pangs are short term and a cup of green tea solves the problem.

Wednesday was a little different.  I found that I didn’t eat any more than I normally did on any other day, but the lack of food the day before made me lethargic as far as exercise is concerned.  I found it difficult to get through my session with the same gusto I normally display and really just went through the motions without performing at the usual level of energy.  I decided that Wednesday would be good as my rest day for the week.  I could eat normally and build up for exercise on Thursday.

But Thursday came – my second fasting day- and I found when I was using the Wednesday as a rest day in the second week I still hadn’t fully recovered from fasting on Tuesday.  I was more lethargic that I had been on the Wednesday when I had trained and actually couldn’t get through the session.  When I started to see stars I abandoned my fast for the day and stopped exercising.  I thought that perhaps I just need to adjust to the new routine and next week would be better.

The third week was exactly the same.  Tuesday was good, Wednesday was a rest day with normal food, and Thursday was my second fasting day.  Again, I was very lethargic and unable to finish my session, and again my vision started to blur so I abandoned my fast and ate normally for the rest of the day.

So for me this is not a suitable diet pattern.  It is possible that I could do 6:1 but I don’t see the point really.  Ok – fair enough – I wasn’t doing it to lose weight I was just checking it out, and maybe if you have the spare supply of body fat things may be different.  But I’m not so sure.  This seems like the eating pattern you can manage if you don’t like to exercise.  A bit like Dr Mosley apparently.  The dangers of dieting without physical activity are well documented – loss of muscle mass, reduced cardiovascular function, decrease in metabolic rate etc. – something I’ll go into another day and all things that have consequences for the dieter beyond the period of dieting.

So… the bottom line… I wouldn’t recommend intermittent dieting if you intend to exercise as part of your weight loss regime.

The next challenge then… meal replacement diets and exercise.

I’ll keep you posted!