Weight up but measurements the same

Are you eating at a deficit?

Nope. Average 2000kcal per day on non-running days, then eat about an extra 300 on running days.

What's a TDEE? I measured my thighs. They are 20inches and have been so for ages, even at 61kg. They do feel a bit tighter, although I'm never 100% sure what's real and what's psychological!

You really shouldn't have gained even half a kg. 7700 calories = 1 kg. Based on my calculations (50 cal/day x 8 weeks) you only have a surplus of 2800 calories.
This is likely just a fluctuation.

ETA: Forgot that you eat more on running days, giving you a weekly surplus of 1550 and an overall surplus of 12400. This is 1.6 kg. It's likely largely lean gains if your measurements haven't changed .

I don't understand. How can it be a surplus if I've burned it off? Surely its just "breaking even"?

You really shouldn't have gained even half a kg. 7700 calories = 1 kg. Based on my calculations (50 cal/day x 8 weeks) you only have a surplus of 2800 calories.
This is likely just a fluctuation.

ETA: Forgot that you eat more on running days, giving you a weekly surplus of 1550 and an overall surplus of 12400. This is 1.6 kg. It's likely largely lean gains if your measurements haven't changed .

I don't understand. How can it be a surplus if I've burned it off? Surely its just "breaking even"?

Your TDEE is roughly 1950. This includes your exercise, and you do not eat those calories back. You already eat 50 calories over your maintenance weight (2000 in - 1950 out). This will lead to very, very slow weight gain. If you eat an additional 400 calories three days a week then you are at a surplus of 1550 per week. ([50 x 7] + [400 x 3]). This is an 8 week surplus of 12400. Where 1 kg = 7700 calories a surplus of 12400 = roughly 1.6 kg.

ETA: My conclusion that this is mostly lean gains comes from the very slow rate at which you put the weight on and assumes a diet that is fairly optimal for anabolism. There is no way to really tell without calculating your body fat.

This is a very exact equation. You're basing this on me eating an extrra 50 kcals a day but that's assuming that my calories counting is 100% accurate (and so are the labels). It dont beleive its the exact science you're explaining it be...what if I move around slightly more at work and therefore end up inadvertently burning those 'extra' 50 kcals? I eat an average, not an exact sciene as I am not a machine.

Thanks for your help but I think maybe you're over thinking this an an exact science. None of us know 100% how much we consume and burn - there's not way of knowing we make suppositions based on what manufactures say and what activity we do.

Also my suplus is being burned so I cant be "carrying" 12400kcals - they've been used up!

I say no chance you put on 1.5kg (over 3lbs) of muscle on just running.

How are you estimating your calories burned?

Not estimating: counting. Weighing, measuring. However, I was trying to illustrate above that although I may think I am accurate, I dont know how quickly/slowly my body is burning a calorie compared to you, for example. We are not all the same. So how can this weight "gain" be explained? Muscle AND water? It's so easy to assume I am overeating but is there something else we're missing here?

You really shouldn't have gained even half a kg. 7700 calories = 1 kg. Based on my calculations (50 cal/day x 8 weeks) you only have a surplus of 2800 calories.
This is likely just a fluctuation.

ETA: Forgot that you eat more on running days, giving you a weekly surplus of 1550 and an overall surplus of 12400. This is 1.6 kg. It's likely largely lean gains if your measurements haven't changed .

I don't understand. How can it be a surplus if I've burned it off? Surely its just "breaking even"?

Your TDEE is roughly 1950. This includes your exercise, and you do not eat those calories back. You already eat 50 calories over your maintenance weight (2000 in - 1950 out). This will lead to very, very slow weight gain. If you eat an additional 400 calories three days a week then you are at a surplus of 1550 per week. ([50 x 7] + [400 x 3]). This is an 8 week surplus of 12400. Where 1 kg = 7700 calories a surplus of 12400 = roughly 1.6 kg.

ETA: My conclusion that this is mostly lean gains comes from the very slow rate at which you put the weight on and assumes a diet that is fairly optimal for anabolism. There is no way to really tell without calculating your body fat.

This is a very exact equation. You're basing this on me eating an extrra 50 kcals a day but that's assuming that my calories counting is 100% accurate (and so are the labels). It dont beleive its the exact science you're explaining it be...what if I move around slightly more at work and therefore end up inadvertently burning those 'extra' 50 kcals? I eat an average, not an exact sciene as I am not a machine.

Thanks for your help but I think maybe you're over thinking this an an exact science. None of us know 100% how much we consume and burn - there's not way of knowing we make suppositions based on what manufactures say and what activity we do.

Also my suplus is being burned so I cant be "carrying" 12400kcals - they've been used up!

I think scottaworley was right here - the Total Daily Energy Expenditure (TDEE) calculation gives you a value of what how many calories burned on average each day, and that total includes the running you do - that's why it asks how often you exercise (and I am assuming you picked the 3 or 4 times a week option). You don't get a surplus on top of that to "eat back" on rn days because it's already built in.

If you want to maintain your weight, you should eat at your TDEE every day, including the days you exercise (and don't eat more on those days). If you need more food on days you run, you should trim calories on non-workout days to keep your daily average around the 1950.

BUT I dont need to lose weight. I have a BMI of 22 and for a woman of my age, height and weight and professionals say one should not be eating less than about 1950-2000 regardless of exercise. 1950 - the 400+/- burned from exercise would mean 1550. I have never eaten that. I have stayed at 61kg for the past year eating 2000cals a day. The only thing to have changed is MORE exercise, hence me asking about the weight gain!