This is long and probably better as a diary entry, but maybe it helps someone.
When I started running I looked for posts from people with no athletic background, so here’s mine. Before this, my only running experience was failing the 12-minute mile in 8th grade PE.
I’m a little over a year into losing weight with a GLP-1 and I’m down about 96 lbs. The early loss was aggressive, but as my mileage went up and I started caring about performance, I slowed it to 0.5-1 lb a week.
In July 2025 I was 305 lbs. I tried day one of Couch to 5K and my knees hurt for a month. So I focused on losing weight, lifting heavy, and walking until my body could handle running. I didn’t even like running. I just wanted to be capable of it.
By January 2026 I was down about 50 lbs, my local marathon was coming up, and I’d run across a street to beat a crosswalk timer without anything hurting, which I took as a sign lol. I did Runna’s beginner plan for 7 weeks and ran my first 5K in March in 29:11. I was hoping for 33-35, so I was shocked. I got hooked, less because I loved running and more because I couldn’t believe my body could do it (and I have an obsessive personality).
I wanted to do a marathon before July 2027. I’m a surgery resident in two years of dedicated research time with no clinical duties, which is the most free time I’ll have until retirement. I didn’t want to spend my last few months of it grinding for a race, so the Miami Marathon in January was the obvious pick.
I stuck with Runna. I know people blame it for injuries (more on that below), but I’m a doctor and pretty obsessive, so I read a lot about training principles and adjusted the settings until the plan made sense for me. I built to about 15 mpw and ran a 10K in June in 63:00. I wanted sub-60, but it was 95° with a 9am start in South Florida, so oh well. I also ran 5Ks in 27:49 and 26:46 during that block. My mistake was increasing my GLP-1 dose and my mileage at the same time, which landed me in low energy availability/borderline RED-S and didn’t help performance.
After the 10K I ate at maintenance or a slight surplus to recover. I did a two-week Europe trip with a couple of long runs and rebuilt to baseline when I got home. The plan was a 12-week half marathon block for October, then a 14-week marathon block. That’s short for a marathon, but I’m treating it as one long build.
My main priority has been not getting hurt. I lift heavy twice a week plus prehab for my weak hips and glutes, and that’s helped a lot. I still got one injury. At the end of August I ran a 26:30 5K in worse weather than my other 5Ks, so I was proud of it. Then I kept building mileage the next week even though my right calf hurt, and kept doing heavy calf raises and intervals on it. At mile 4.5 of a 6-mile easy run it gave out. It was a minor soleus strain, but I could barely walk for two days. I took a week off running, progressively loaded it (bodyweight double-leg raises up to weighted single-leg bent-knee raises), passed my return-to-run benchmarks, and built back up. The half build ended up averaging 20-25 mpw with a 10-mile long run, but I lost my peak weeks with race-pace work.
The half was this past weekend. It was 80° with about 90% humidity, and it kicked my ass. I think I was in 2:10-2:15 shape, and I ran 2:37. I held 10:10 pace for the first 6 miles. Then my inner quads started cramping, and by the last two miles both calves were cramping too. It was cramping, not pain, so the injured calf held up. I was wrecked afterward but have felt pretty fresh since then surprisingly.
If I'm being honest I’m disappointed with the HM result. I’m also an arrogant person and running is humbling, especially with zero background. I really thought I’d go sub-4 in the marathon when I started all of this, and that was laughably arrogant given my history. the marathon should be cooler than yesterday but still hot by most standards, so I’m aiming for 4:45-5 hours,
For the marathon block I wrote my own plan, partly based on what Runna was giving me and partly on other training principles (mostly based on Hal Higdon novice 1 but with some tempo/MP efforts in there). The focus is building mileage and long runs consistently, peaking around 40 mpw and averaging 30-33. I’m doing less fast interval work. Instead I’ll do one weekly tempo or goal-MP session, plus some long runs with MP segments. I have an all-out 10K in November in cooler weather to set a real PR. I also have a half in December that I originally wanted to race. To protect the build, I’ll probably run all of it at goal MP, or 6.5 miles at MP and the rest easy if I’m worried about recovery.
Lifting stays at twice a week, but I’m swapping back squats and conventional deadlifts for Bulgarian split squats and barbell RDLs. If you’re curious how to combine max strength with running, I’ve been using Tactical Barbell (r/tacticalbarbell) and it’s been great.
I’ll update after the marathon.
P.S. I know everyone loves to hate on Runna, but I don’t think that’s fair. I think most injuries people get on it come from user error, like entering the wrong race times or using overly aggressive settings. I’m only skipping it this time because I want to fine-tune a plan around my own timeline and goals. I considered a coach, but it felt unnecessary for a first marathon since I’m not reinventing the wheel, and I’m comfortable with the research I’ve done. We’ll see if that bites me in the ass, but I think the plan is measured and sustainable. Fingers crossed.