I did some lengthy fasting last week then in the ensuing days and the weekend didn’t eat vast amounts. The most I had was on Sunday when I ate two crumpets with butter, marmite and peanut butter on them in the morning, a small portion of chips midway in a 13 mile walk early afternoon and then a salad in the evening. Total calories was probably about 1500Kcals which, with a BMR of 1700kcals and the walk ranging between 900 and 1300kcals, still left me with a hell of a deficit. And this week I fasted again on Monday and Tuesday, and will continue through till this evening – effectively 3 days since that salad on Sunday night.

I’m happy with the weight loss. Prior to the week before last I was averaging 188lbs – often straying up over 190. I weight myself in the morning before I’ve eaten or drunk anything and, obviously because of fasting, this morning I was dehydrated, but still I cracked the 180 barrier at 179.4lbs.

Noticeable this time has been ketosis. I bought some ketosis sticks to check on this and last week was disappointed with a reading (pale pink) that indicated a minimum ketone level in my urine of 0.5 to 1.5mmol/l. However, reading up on the subject I found that lots of things can affect this. Hydration dilutes those ketones while, if you exercise, you burn them. The ketones are fuel from your fat so finding them in your urine means unburnt fuel. Still, nice to have some indicator of how I’m doing beyond the weight drop. On Monday I was still getting the same reading. However, on Tuesday evening I started salivating and my pee smelt of fruit (which is an indicator). The reading today is now up to 3.0mmol/l+. Hydration is a factor, but still, I’m happy about that.

Now I have also checked back to when I last fasted the February before last. I notice that I dropped plenty of weight going from approx. 185 to 172, but apparently I didn’t record my weight thereafter for two months. I think I understand why. The fast had been an easy quick fix I felt I could do any time, so I didn’t bother about what I might be putting on. Turns out, two months later, I was nudging 190lbs. Thereafter I often felt very tired and subsequent attempts at fasting often failed. I now, having read a series of blogs on the subject, know why.

It’s all about the body conserving its energy. If you just diet (my fast was just a one-off so didn’t have the required effect) the body tries to hold onto its resources by burning less. This is why dieting has such a dismal success rate. A person will diet, the body resets, and then when they continue eating a lesser amount, because they are burning less they retain more. Also, because of that reset, they feel more tired and miserable eating a lesser amount – a recipe for failure. It is all about insulin and, if you are interested, you need to read through the blog linked on that subject. Conventional wisdom has it that it’s all about calories in, with calories out being secondary. I believed this too but now know it is more complicated than that. It’s about your body’s ability to burn calories. It is more about the calories out than the calories in. And insulin is the lighter.

So what to do? Apparently you need to fast, intermittently, for a longer period – maybe a month – to get your insulin down and reset your body to run how you want it to run. It’s stubborn, the body, and resists change. Read that blog – there are 27 posts.

To this end I intend to make intermittent fasting a habit. I will continue with it strongly until I am down to a suitable weight. I have always had a low regard for BMI calculations because, apparently, I need to be between 130 (9st 4lb) and 170 (12st 2lb). BMI is all very well until you start weight training, I felt. The idea of going midrange here at about 150 (11st 10lbs) seemed frankly ridiculous. Now I am not so sure. I remember, shortly after my wife died, getting down to that weight. Mentally I was a mess, but physically I was very good. I felt light, clothing fitted well, and, as I recollect, I was fit enough to do10 miles of gorge walking in the Cretan mountains followed by a swim of a mile. The method was effectively the same as I intend now, which is not eating much and exercising a lot, though the impetus behind it was not so good. I intend to aim for that region, but for better reasons.

However, I have been weight training and put on a lot of muscle, so, it seems feasible that my ideal weight should be somewhere in the upper range of my BMI. 12st seems like a good target. I’ll aim for that and see how it goes. In the end it comes down not so much to BMI or weight, but how much fat there is around my waist and, as I once noted long ago, whether or not I can tuck in a T-shirt and feel I don’t have to hold in my gut.