Is it realistic to get much faster just by dropping weight as a masters runner?

Yep. One way to improve your Vo2Max is to lose weight. Period.

Fast when you can. Eg skip breakfast, no late night snacking. Maybe 24 hours from time to time. Carb fast, or low carb when you can. Eat lots of vegetables and fruits, especially lower calories. Plenty of fiber, which the plants will help with. Balanced diet with lots of vitamins. Healthy meats, beans, nuts. You can still eat some desserts, as long as you've gotten your 10 servings of fruits and veggies and 10 glasses of water. Keep the portions reasonable and try not to send yourself into glycemic shock (eg 40 grams of sugar in a soda). The fiber will satiate, and the lack of refined sugar will allow your leptin to function. The goal is not to be hungry, it's to burn fat.

Lastly, if you're single, become infatuated with someone to the extent it stops you needing to eat. You'll regain it if doesn't work out though.

I really hope OP is like a taller version of Yomif Kejelcha trying to lose weight at 7', 170 lbs so he can dominate local road races.

I put on about 15-16 pounds after a sub 3 marathon as a master's runner. Some fat, but I took some time off to regain some muscle in the gym. I looked, and felt, quite a bit better. I was able to stay within 15 seconds of my 5k PR. But my marathon time suffered substantially. It's a lot to ask of your body to lug that extra weight over 26 miles. You'll wear out in the later miles, at least that's been my experience. But everyone has to find that right balance between being healthy and lean.

Last year at the USATF Outdoor National Championships there were events for the 25-29 and 30-34 age groups.

160-165 pounds. Very lean at the time, probably 10-11% body fat on my 6'2 frame.

What was your diet at 160 pounds?

This is absolutely terrible advice.

Low carb is quite possibly the worst diet for a runner. from a exercise science perspective, running is basically a sport of who can convert carbs into speed best. Not having enough carbs is terrible for running. For example, it's impossible to truly sprint in a carb depleted body (read up on the glycolytic pathway).

I've actually lost weight by eating more carbs before and during my runs. Not only do I feel better on my runs, but I perform better and most importantly I'm less likely to be starving after.

For me, avoiding acute unmanageable hunger is how I lose weight. This means eating regular food at meal time until i feel full and snacking on high carbs before and during workouts.

Honestly, I was just always that rail-thin kid. Until my 30s it seemed like I couldn't put on a layer of fat if I tried. One of those guys with a metabolism seemingly in hyper-drive, and between that and being in endurance sports I was just always thin (though adding a little muscle once I started lifting a bit in my 20s).

A combination of training less and probably age has slowly changed things from about 35 to 45. I look lean but not skinny or ripped, and I'm not sure if it looks 'better' or worse at 175 vs 160. Possibly a healthier appearance to the average viewer, ha. But the physics of it suggest that it isn't going to help with running performance.

I am trying to get back to decent training and will see what happens!

No.

Yes, total carb fasting like keto is probably bad. Carb cycling in a low carb diet however can be beneficial long term.

If you go lower carb while base/easy training, and consume carbs around your workouts, you can still crush your workouts while still developing your fat oxidation during easier training and rest.

Also, many who eat a low(er) carb higher fat/protein diet report that their appetite becomes a lot easier to control and that they don't get ravenously hungry as often (if ever) as they did on their prior normal diet.

I’m not a dietician, but I’ve had the best results as a runner by limiting dietary fat. Less things like pizza and burgers, more pasta and rice bowls. I also like salads with sweeter dressings. I feel better on all of my runs if I’m on a carb heavy diet, and with a net calorie deficit those carbs are not being turned into stored fat.

as stupid as this question, young people don't know until learned

at 150 lbs this guy will break 230 very easy.

of course this assumes a normal build and 6 ft 1 and under.

Thanks for the replies and insight so far. To clarify, I have an pretty good idea of how to burn that amount of fat safely while training. What I'm wondering is how likely it is that that will translate to significant speed gain, like the 1.5s/km per lb lost, or if it'll likely be much less than that.

I know there's only one way to find out ;) but if anyone has any more insight or experience with this, please do share.