If anybody ever suggests you try interval training, stop them, turn around, and run away. On paper, “Intervals” sound simple: you sprint for 40 seconds, walk for 180 seconds and repeat five times. What they don’t tell you is that your heart is likely to explode right about the third repetition. It is pure hell!

I had my first experience of Intervals today. I woke up bright and early, put on my running clothes and ambled to the park.

In addition to the intense physical pain Intervals induce, the experience also induces the most intense feelings of embarrassment and humiliation — I lost count of the number of dog-walkers that looked at me with a mixed expression of pity, confusion and just a hint of fear.

Twenty minutes later, I crawled back home oozing sweat and, quite possibly, internal organs. Thank goodness today is high carb day — bring on the potatoes!

Second day of my new three day programme. I had a sneaky suspicion when I woke up this morning that today would be legs and I was right. I don’t know why, but I hate training legs. My previous trainer of four years ago was also obsessed with legs. Perhaps it is drilled into them and PT finishing schools. At least they are all consistent with each other.

Today was a very exciting day! Not only was I allowed to eat carbs, but my programme changed. I have switched from a two-day cycle to a three-day cycle. Why I find this exciting is beyond me too, but it was nice to do different excersies –yes, they were equally hard, but at least the fact I had never done them before could justify my poor performance. Today we focused on shoulders, back and abs and the session was a lot more satisfying than Tuesday’s disaster! I felt I had made progress and I know I will be sore tomorrow.

I was, however, incredibly disappointed with my carbs: I had oats with no milk, no sugar, no fruit and definitely no fun. I am now convinced oats are the food of the devil and I know why I have avoided them for the past 38 years! The next time I am lucky enough to eat carbs, I will stick with what I know and eat a potato instead.

Gym was not so good today: I just couldn’t do as much as I normally would. I have no idea why, although I did go to bed much later last night and perhaps that was the reason. Regardless, I am not going to let it get me down. We all have our off days, don’t we?

On a more positive note, I have lost another 0.7 percentage points of body fat and I am now 8.1%. I have also lost a little weight (just less than a kilo). And, the most exciting thing of all, my diet is being revised and I will get to eat proper carbs! I have never been so excited at the thought of eating a boiled sweet potato!

My trainer has asked whether I would be able to train four times a week — like the idiot I am, I agreed. I have invested so much already, I might as well go the whole way.

I trained with one of the most experienced and senior PTs at the gym today (in fact, I think he might have been a Director) and boy did I know it! This guy is even more imposing than my regular trainer and has a demeanour that says “do not **** with me!” This is the type of guy I had imagined training me before I signed up for the programme. I have made many foolish and incorrect assumptions over the past few weeks, but one assumption I got absolutely spot on: it is incredibly difficult to give up when a giant it looming over you demanding one more rep.

After the hour long session that felt like four, I felt fantastic about what I had achieved and I even managed to get a cheery wave goodbye from my tormentor! I am not looking forward to the full-body-aches tomorrow.

My regular trainer is away on a course and so I have another trainer today and Saturday. Today I trained with a Junior PT (my regular trainer is a Senior PT). He did a good job and certainly pushed me to my limits. My only complaint: since when has a half a rep plus a half a rep equalled zero reps? I knew that educational standards had gone down in this country, but really?!

After two weeks of training and one week of dieting, it is time for the weigh in.

My weight has remained the same at around 57.5kg, but my body fat has reduced from 13.3% to 8.8%. My trainer remeasured at least three times to be absolutely sure and seemed more excited about this “achievement” than I did. I was obviously pleased too, but 8.8% doesn’t mean an awful lot to me — I just wanted to get to the 10% that most people aspire to.

The rest of the session was great. Although my trainer has always been incredibly enthusiastic (and demanding), today he seemed even more enthused. At the end of the session, he told me that he couldn’t wait to tell his colleagues. He also said that I could be his best ever transformation, so I had better not mess it up — no pressure on me then!