Hi,
The short answer is, I don't know if I can answer that question, even having looked at RIS-3451-TOM.
However, my thoughts:
* Remember: there are more lenient requirements for existing drivers than new drivers.
* Looking around our messroom, there are many drivers who look like they don't often miss a meal - it's nice that at work I'm probably about average and everywhere else, larger than average! Drivers are not known to be beanstalks (and I don't think the job helps us maintain a healthy weight, either)
* I think the important bits are the ECG and whether you are fit enough to perform your duties - you've told us you are for the latter, and hopefully your ECG is okay, too.
* If, unfortunately, you are not fit enough, I understand (at our place at least), you have some time to make any necessary changes if it's possible to regain fitness.
Have you spoken to your colleagues?
If I were you, I wouldn't stress too much. Fingers crossed all is okay, but worry isn't going to help (easier said than done, I know).