canklecat

None of us here is training for the TdF. The OP is 59 years old. No amount of conditioning, weight or BMI will make us candidates for a grand tour. BMI is practically irrelevant to guys our age who just want to keep up on group rides that we consider "fast" but wouldn't even be a recovery ride effort for pros in their prime.

Obsessing with weight loss and optimal BMI is a sure-fire way to suck all the pleasure out of spirited group rides appropriate to our age. The OP might be able to lose 10 lbs without too much suffering, but what's the point?

At 5'11" and 150 lbs, I'm already within 5 lbs of my optimal weight when I was a competitive athlete in my early 20s... which was 40 years ago. There is no diet that will compensate for aging or magically turn me into a mountain goat on a bike. VO2 Max gradually fades and we don't get it back.

I've ridden with a bunch of MAMILs who are semi-fast for guys in their 50s-early 60s. One guy is a former world class track athlete, but now about 50 lbs overweight at around 200+ lbs. He drops me on climbs. Because he has a lifetime of conditioning and a genetic advantage that most of us never had -- that kind of VO2 Max is mostly a gift of nature. The rest of us are trying to compensate for our very ordinary aerobic capacity but will never be anywhere close to elite athletes. Sure, if we had any real climbs, like mountains, I might catch and pass him gradually... until he got serious about losing a little weight. But on our roller terrain? Nah, he's always going to be faster because he worked at it from the time he was a kid to finely hone his existing capability.

Focus on appropriate training for the weakness. In this case, an occasional session with HIIT and polarized training to improve climbing for the usual short, steep climbs and roller coaster terrain. Maybe once a week, twice at most, depending on our schedules, since we probably also have lives apart from cycling.