Gain Weight & Run Slower

So I been agonizing over my lack of form this year. I thought I got it figured out that the reasons I been running slower are:

1. Age – Soon gonna be half a century old. Cannot expect to be able to maintain the same type of performance.
2. Mileage or rather lack of mileage. Since 2008, has been running shorter distances and average mileage per week is about 30km. Certainly not sufficient to even maintain previous speed.
3. Speed – again the lack of speed training. Speed training or interval training or tempo run is something I don’t really like. Without that, how to possibly improve?

 And now to add on to my excuses, a new discovery. This year, I consciously put on another 4 kg +/- 1 buffet dinner. Reasons being that I didn’t want to look too gaunt and somebody claimed a little bit of weight can put more power into my run. But now I found out that actually for every 1 pound of weight lost, I can (or should) get up to 2 second faster per miles. So if I reverse that logic, for every pound of weight gained, I will run 2 second slower per mile. So I gained 4 kg which works out to 10 pounds which if I read this table correctly means I would have run 4:22 minutes slower! And which is just right for the type of timing I have been getting for my half this year.

Ah so now I know the real reason why I am slower this year. Time to lose that extra 4 kg. But maybe can wait until next Chinese New Year.