Fuller wrote:
Putting the focus on weight loss is a mistake. Concentrate on quality productive training and you will be stronger, aerobically fit and likely the same weight or lighter.
Agreed. Unless you are already capped out on your potential fitness (lets face it...none of us are), then focusing on solely on weight loss comes at a sacrifice of focusing on fitness. Remember, it's not just a kg formula when climbing...it's W/kg. Meaning increasing watts (or not losing watts) is also important. How important of course depends on the grade of the hill. But from my guesstimate, 20 seconds for 1 pound on an hour-ish race sounds like about 5-6% average.
I do 3 major hill climb races a year. One is a true TT, and the others are basically treated as TTs. All of them average between 5.1 and 5.7% and basically it comes down to 1 pound plus/minus is the same impact as 1 watt. For steeper climbs, say in the 10% range, I find that 1 pound plus/minus is about 2-2.5 watts. Naturally on a shallow 2-3% climb, it's the opposite where 1 watt plus/minus is equal to about 1.5-2 pounds.
So in the OPs case, you need to figure out not just the time savings per pound, but the time savings per watt. Then ask yourself which is easier. Losing 4-6 pounds and maintaining your 1 hour power, or gaining 4-6 watts in 1 hour power and maintaining weight. Or more likely a combination of both is the best solution. Given you're already fairly lean, I would focus a little more on the fitness side since that's likely the lower hanging fruit compared so someone 25% body fat.