Why Is My Pants Size Going Up?

Did you recently start lifting weights and your pants feel a little tighter?

And not just in the legs and butt where you might expect it, but even the waist feels tighter?

If this sounds familiar, you are not alone. It is a common pain point for many women new to lifting weights. Before you decide on just giving up lifting weights altogether, keep in mind that this is probably only a temporary dilemma–and it happens to most women. You’re not alone.

I have heard this question many many times and like any good coach, I have hypothesized and researched the answer for this waistline increase phenomena. I have talked to other strength coaches, read journals, and followed up with many women who have shared this problem in the past. And I have discovered a few interesting facts.

  1. The first and probably most important discovery is that this condition seems to be temporary (less than a year) for women who continue to strength train. (But more on that later.)
  2. The second thing is that there seems to be two different reasons for why this phenomena occurs. And often women will actually experience a combination of these two reasons when it comes to pants size — especially with jeans.

Reason One:

jeans2I will call the first reason, the Why-My-Jeans-Don’t-Fit-Transition-Model. As we have discussed on this site before, muscle gain happens before fat loss. Yes, eventually fat loss speeds up due to muscle gain, but there is a transition period where muscle growth happens and fat loss has not yet begun or has begun but at a considerably slower rate. Furthermore, a muscle increase in the legs, butt, and abdominal area can happen rather quickly. All three increases could potentially make your jeans feel tighter. But for reason number one, I want to focus on the waistline.

There are several different muscles in your abdominal area. The ones that will likely grow from your typical multi-joint exercises (such as squats) are the muscles that make up your anterior abdominal wall. Namely, the internal and external obliques and the rectus abdominus. There are other muscles that make up your abdominal wall, but these three seem to have the most early growth as a female athlete begins to develop her core.

NOTE: developing your abdominal wall is one of the best things you can do for your physical and functional health.

As you are probably aware, when muscles are exercised, they breakdown and when they recover they often grow back stronger and even bigger. Sometimes we use the word hypertrophy when referring to the growth in muscle size. Abdominal muscles are not necessarily known for significant hypertrophy but some growth does occur in most new lifters who had little to no initial abdominal musculature.

This growth is a good thing. You want a strong abdominal wall.

Because there is a time where your abdominal wall is growing and fat loss has not yet happened or is happening slowly, we often will see a transition period where the waistline will actually increase in the initial stages of muscle development.

For demonstration purposes, I have included a transition model below. As you can see in the orange line of this example, this person started with a waistline identified as 5.75 units of linear measure in January of a given year. The good news is by September, her waistline dropped to 5.265 units of linear measure — and this was one of her fitness goals. But look at March through July — those must have been some frustrating months.

jeans-transition-modelAs you can see in the purple line, this lifter’s abdominal wall grew stronger and slightly bigger, which increased her overall waist size. And this happened at a higher rate than the rate at with body fat decrease as you can see represented by the green line.

But this is super important. Notice her abdominal wall is actually at its biggest in September when her overall waist size is at its smallest! So long story short, do not be afraid to grow your ab muscles. Success is right around the corner.

Reason Two:

Companies that make female pants, particularly jeans, suck.

It turns out that most companies want to make jeans that will fit the most average women. And most women don’t have sufficient muscle. So jeans are designed to make most women look better so that most women buy said jeans.

Diamonds? No. Yoga pants are a girl's best friend.
Diamonds? No. Yoga pants are a girl’s best friend.

Believe it or not, I can relate. Fortunately, I wear men’s clothes and our issues are way less bothersome, but men with muscle often run into similar issues with dress shirt and coat sizes. I have never exactly been a bodybuilder, but in my younger, more athletic days I had a neck size of around 17. The problem was, most men who wear a size 17 shirt are much much bigger than I was. In terms of overall size, I actually probably fit best in a 15.5 shirt but I couldn’t button that top button to save my life. Suit coats and sport coats are an even bigger problem. A muscular guy might wear a 46″ coat because that is how big his chest is, but he may have a 32″ waist. Most guys who wear a 46″ coat though have a 50″ inch waist. So guess how coat companies make those coats.

Most women who lift weights know this all too well. To find a pair of jeans that fits over your muscular quads and butt, you have to go up several sizes, only to have the pants too big on your waist. The size jeans that women who lift need to fit around their trim waist is typically a size that they can’t get past their thighs. I believe this is the reason that yoga pants have become the go-to pant choice for all athletic women: they can stretch around the thighs and glutes and still fit snugly at the waist.

So you are no longer average. You are superior to average.

Your reward? Jeans that don’t fit.

The good news is that some clothing companies are starting to realize that women enjoy squatting and that muscle is sexy. There are some jeans companies that do make jeans that might fit better : Relentless and Barbell Apparell specialize in denim for lifters, and some women have even reported that Lucky Brand jeans fit well.

Finally, and this is probably the most important part: You are beautiful.

Many of ushellys exercise because of the shame we feel from not fitting in with all the ideal images we see in the media world. But these images are often false realities. Most of these ideal images are photoshopped, taken at ideal angles, of models who cut calories for their shoot — THEY ARE NOT REAL.

Stop looking at them. They only make you feel shame and shame should not be the reason we work out. I know we are all guilty of this. Even men are guilty of this. But we have to stop. Comparison is killing us.

Exercise for your health. Muscle is healthy. Grow it, and know you are beautiful.


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The formula is simple. Sensible Strength Training + Real Natural Food = Healthy Beautiful You.

Good luck and have fun! We are here to help.