Intermittent Fasting: Lessons learned in week one

Alistair Hall

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Well here we are. Its January and time to start my intermittent fasting (see blog entry below Intermittent Fasting: The Medi-Guinea Pigs Prepare with an IGF-1 Test)

The idea is that by severely restricting my calorie intake on two days a week I will reduce my IGF-1 level and consequently live longer. It sounds a bit too easy, but according to an increasing body of research this is the case.

I had my IGF-1 level checked towards the end of November and it was actually already towards the bottom of the normal range - my IGF-1 was 15.2nmol/l, normal range for my age being (12.2 – 32.8). I (like millions of others) overindulged over the holiday period so I am aiming to have my IGF-1 tested again to see whether my unhealthy lifestyle over two to three weeks (7 Christmas lunches excluding the real one!) has made any difference.

I did a little bit of homework before I started as I wanted to get some idea of what 600 calories a day looks like. I am not ignorant as far as calories are concerned, but I normally look at the big picture of my probable intake and energy output over a week. As my weight has remained fairly constant at around 11st 9lbs occasionally falling to about 11st 4lbs during marathon training and rising to its highest level of 12st 2lbs at the start of this week (I think I mentioned I let myself go a bit over the holidays, but it’s all in the interest of science so that’s okay!) my calculations are clearly not far off the mark. However, when thinking about daily calorie amounts in the hundreds then it's a different matter - hence the homework.

So one day a couple of weeks ago, while thinking about this challenge, I decided to give it a quick trial run. It was coming up to lunchtime and although I hadn’t eaten anything by then I had drunk a glass of orange juice and several cups of coffee with milk. I thought if I am going to do this properly I had better make at least a reasonable estimate of how many calories I had already consumed in my drinks. To my surprise it worked out at about 200 calories, a third of my daily allowance and I hadn’t even been conscious of it!  Perhaps this was going to be harder than I thought.

Not to be discouraged (after all this was only a trial run) I went down to the supermarket and wandered round trying to get inspiration for a low calorie meal. I decided to make a prawn stir-fry with Singapore noodles. I won’t pretend that the food labelling in this particular supermarket was overly helpful (I will blog about that another day), but being a numbers kind of guy I managed to work out in the shop that if I ate half the noodles, which would be plenty, then I had about 450 calories worth of food. Having done my homework, I already knew that one tablespoon of cooking oil was a staggering 145 calories so assuming that the soy sauce I intended to use was not more than 5 calories (it wasn’t) then I had a 600 calorie meal. I have to admit that I was pleasantly surprised that I had a substantial plate of food and not only that it had actually been quite good fun working it all out. Perhaps it wasn’t going to be so bad after all.

I am now into my second day of calorie restriction. The first day went surprisingly well and so far today, even though I've eaten nothing (and it's already 3pm) I'm feeling good.

So what are my lessons learned in the first week?

The first thing I have learned is that green tea first thing in the morning is just as nice as ordinary tea and that black coffee is okay - a lot of calories can be wasted in making the wrong drinks choices.

Second, it suits me better to save all my calories up for one fairly substantial meal at the end of the day. I'm quite used to skipping breakfast and even lunch on busy days so this isn't a great hardship for me. More to the point, 500-600 calories in one meal can be surprisingly satisfying (last night I had lamb's liver (166g) fried with half an onion (106g) using only one teaspoon of oil, but still 42 calories, new potatoes (200g), broccoli (166g) and two teaspoons of gravy granules made up (17 calories) and a teaspoon of French mustard – total 565 calories).

Third, it is so important to weigh your food and check the calorie content especially when you have so few calories to play with. A wrong guess could easily sabotage your fast for the day.

I am having another blood test tomorrow to see whether my indulgence over Christmas has made any difference to my IGF-1 levels - I'll post the results when I have them!

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