Weight Loss
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Running and Weight Gain- Is it Muscle?

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I have been a big runner for a while, although lately I have been stepping it up alot. I used to walk a lot during the day but I got a full time job so now I am quite sedentary. However, i thought I was making up for it by running 4 miles 5-6 times a week plus doing some yoga. 


I went on a vacation where I sat around all day for 3 weeks and lost about 8 pounds, however since coming back and sticking to the exact same diet (if not less food) and running this much, I have gained those 8 pounds plus a few more! I cant tell if its fat or muscle, but it seems odd to gain that quickly in 3 months especially when my diet is so clean and I exercise so much.


By the way I am a vegan, I rarely eat grains, I eat all vegetables, minimal fruit, no sugar except some dark chocolate at night and only drink alcohol once a week. ANY THOUGHTS?


I once heard that running can really bulk up thighs, but I dont know if that is true or not, but it seems interesting that I lost weight doing no exercise but gain when I do exercise!

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No it's not muscle. Not in that little amount of time anyways. 

It takes a minimum of 4-6 weeks for muscle growth to occur-- it takes this much time because there are many processes taking place at the cellular level of the cell. Your DNA has to change first before muscle growth physically occurs, and even then it's not much. 

It takes a lot of effort, time, proper nutrition, and consistency to even gain a few pounds of muscle. It's not easy to put on muscle, especially if you are a female. 

The most likely cause is swelling/water retention in the tissues from not being active before. This will go away in time as your body gets used to the activity though. 

Other influences could include too much sodium, constipation, weighing later in the day (food/water/waste weight), it could also be your time of the month soon-- women can gain 5-10lbs (or more) the week or two before their period (hormone fluctuations can cause bloating in the tissues)

Also you say that you lost 8lbs on vacation, and gained it back when you got home. 

Perhaps the scale at your resort was wrong?

Nope, I weighed myself before I left and after I came back. same scale.


I dont see how not changing my diet much since being home could affect my weight this much. I have seen my weight go up from running before, but never this much.

3 Replies