Guys running 70+ miles a week: do you still put on weight if you don't watch what you eat?

Yes, I need to log all my calories in myfitnesspal to maintain my weight.

I’m 34. 6’1” and hover right around 155lbs most of the year. I can easily maintain my weight up to about 60 mpw but will steadily start losing weight above this mileage no matter what I eat. I start getting injuries if I drop below 150, so I don’t tend to stay above 60 mpw for long. It’s really hard for me to gain weight, so I tend to be more careful.

31 year old male, 6' tall, typically 70 - 80 mpw in training. Started training when I was 27, played soccer when I was a kid and did 2 years of cross country and track in HS but never took it seriously. Was never lean as a teenager - I'm much leaner now than I ever was when I was younger.

I definitely have to watch what and how much I eat in order to drop or even maintain weight while training. Even eating very cleanly I will naturally tend to put on weight slowly (1 lb / month) if I don't also try to err on the side of only eating enough (eat until just no longer hungry, not until actually feeling full, try to only eat when I'm really sure I'm actually hungry, try to drink some water first when I feel hungry to make sure I'm not just thirsty, etc).

Being mindful but not super strict I tend to sit around 162 - 165 lbs at 10% to 12% body fat during training, as measured by DEXA scans. If I train consistently and am very strict with my eating for several months I will slowly trend downward (~1 lb / month), if training or eating is inconsistent I will trend up. I have driven my weight down to 150 lbs at 8% body fat before by logging food and counting calories for several months, but I was hungry the entire time and felt like a zombie so I've decided it's not worth doing that again (plus I currently run faster at 165 than I did when I weighed 150, so there's that). I will often still force a cut down to ~160 for big target races but I think that once I start to get below 160 lbs / 10% body fat the costs of continued loss outweigh the benefits for me, personally.

Generally no. The hard part for me is readjusting eating habits after a marathon training cycle where I've logged a lot of 70-80 mile weeks. THAT's when I seem to gain. Training for a 10K and eating like your training for a marathon will pack it on.

I think it depends on how much fat you have to begin with. If you are 7% body fat and you run 70 miles per week, you'll gain weight if you arent careful. If you are 20% body fat and run 70 miles a week, you couldnt stop losing weight if you tried. Most people are somewhere between those two. To answer your question, im 34, 5'10, 155. If i dont watch what i eat. Ill get up to like 160. I doubt i could get to 170 if i wanted to, while running 70mpw