Excess body fat has a profound influence on perceived effort. Only a few days ago, I rode down to Palo Alto Bicycles carrying a 16 pound daypack, returning home with a 13 pound daypack (uphill).
That 13-pound pack felt onerous to pedal uphill. Yet only 3.5 months ago, my body weight was 19 pounds higher, reminding me just how significant it is to carry extra flab up the hill, and how it makes both hands and butt uncomfortable on the bike, and fatigues legs and back prematurely. Which is why it’s so hard to get started with serious exercise— the comfort is just not there, the feedback is mostly unpleasant.
But the backpack experience also reminded me that by losing another 15 pounds, the dramatic light-as-air feel holds appeal as a great natural high, a self-efficacy that I will strive for, keeping an iron will on the calories-in front. I am only 5 pounds away from my lightest weight in 20 years, which means it will likely be a serious challenge, with the past three days showing me signs of body-mutiny, with a more demanding hunger than in the past 4 months.
As to power and weight, see these articles: