I have lost about 100 pounds over the past few years, focusing primarily on weight loss. Now that I have lost the weight, and I look kind of scrawny underneath what was fat, I'm trying to gain muscle mass.

I can't see a change in my appearance, at least not yet, because I have only gained 10 pounds since I started attempting to gain muscle, and if anything, I am more toned in my arms, but my pants are getting tighter again!

I have been doing the following exercises among others:

  1. Planks
  2. Side-planks
  3. Back extensions

They all target the area around where I wear my pants; is this normal for muscle gain to make a noticeable difference in 2-3 weeks on waist/hip size for pants?

The difference isn't even one belt notch yet, but I am hyper-aware of how my pants fit.

3 Answers 3


Like I said in your other question. All three of those exercises effect your lower back, obliques, and some of your actual abdominals to a degree..i.e they all work your core. Since you're a beginner, no matter what you do, you will gain muscle where ever you do the work. In this case, you're doing back extensions (lower back), side-planks (your whole core, but primarily obliques, the muscles on the side of your torso and hence waist), and planks (entire core)...Since pants are sized based on the diameter of your mid waist in inches, even a very slight increase in muscle mass in this area will cause somewhere around 0.3-1.5 inches of difference and hence your pants will get tighter lol. So don't worry this is good, unless you plan on becoming a physique model in which case stop working obliques because they'll hurt your v-taper.

I'm not gonna rant about it here, but why are you doing back-extensions? Please do some research regarding this exercise and come to the conclusion on your own how unnecessary and harmful it is..there are SO many better exercises you could be doing, which would all incorporate more muscle mass and strength, and spinal health.


Since you have gained a noticeable amount of muscles while doing exercises for your obliques (obliquus externus abdominis), it makes sense that your waist circumference has minorly increased.

In my opinion, you should look at it in a positive way because it represents the gains you've made, and anyway it's not gonna significantly increase anymore due to this muscle's structure. You can see some crazy obliques here - you probably notice that it has a limited effect on hip size (yet it does).

I read once an interview with a coach who recommends his bodybuilding trainees not to do too much of obliques training because it may be a hindrance on their way toward the V-shape. Yet, if you're not going for such contest, core workout for strength & stability is more important than avoiding another cm in your circumference.


Gaining muscle after huge fat loss should be done slowly as it takes long time for your body to get accustomed to lower body fat level and could gain fat rather easily. Waist shouldn't increase from muscle gain significantly. Take regular measurements of waist and tights. **

On the other hand most people that lift weights seriously have problems finding pants because of big tights. If you regularly squad/deadlift, you will soon have to forget about most "skinny fit" jeans and go towards "loose fit" or certain models of "regular/straight fit" jeans.

** Fat gain is a major concern if you are above 15% bf - if so, try to maintain weight while training with bigger weights and consuming same amount of calories that you burn. After a while go for another cutting period to get to around 10% bf before focusing on muscle gain.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.