Why Is Your Butt Getting Bigger After Starting to Lift Weights?

Woman doing a squat

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It's a sad truth that many people avoid weights because they think their butt will get bigger. Unfortunately, one of the myths of strength training is not only a larger derriere but a fear of gaining more muscle.

It helps to understand what is necessary to actually increase glute muscles and why some changes may only be temporary.

Understanding Glute Development

If you're worried about your butt getting bigger, you're really worried that the muscles in your buttocks will grow larger. The process of muscle growth is known as muscle hypertrophy and it can occur when your body repairs damaged muscle fibers after exercise, increasing the size of the muscle.

However, your glute muscles will only get bigger by engaging in a long-term consistent program of weight training and doing two things:

If you're using lighter weights and doing more reps with less rest time between sets of squats, you're not really doing what you need to do to set off the damage and repair process to get larger muscles.

Additionally, hormones such as testosterone play a role in building muscle mass and strength. Hormone levels vary based on age, sex, and genetics and many people don't have high enough hormone levels to gain exceptional muscle mass regardless of the exercises they do.

What If Your Butt Seems Bigger?

Okay, with that said you might be thinking: "But my butt really is bigger!" You may be tempted to quit weight training and exercise altogether, but don't do that just yet. If it seems that you're getting bigger from lifting weights, don't give up.

It may be because you aren't losing body fat as fast as you're building muscle. This is actually very common when people start exercising.

Role of Cardiovascular Exercise

By varying your workouts between cardio and strength training, you may be able to increase weight loss as muscle mass increases.

For example, research shows that an hour of cardio three times a week may change body composition and support a loss of both body weight and fat mass.

Cardio also offers lots of general health benefits, especially for your heart.

What You Can Do

If you're still concerned about building muscle more rapidly than fat loss or gaining weight, there are some other things you can do.

Double-Check Your Diet

It may seem obvious, but are you sure you're not eating too much? It's easy to compensate for your workouts by eating more than you realize, so keep a food journal to make sure you're not overdoing it. Appetite hormones often increase with exercise making this one of the most common reasons behind a scale that won't budge.

Wait It Out

Calm down and give your body time to respond to your workouts and healthy diet. It takes time to see results and some people won't see them for weeks or months. You'll also find what works for you over time and it takes some patience.

Understand Your Body

When you start lifting weights, you get sore. That soreness is actually small tears in your muscles, which is a kind of inflammation. That inflammation may even cause you to retain water.

What this means is that even though you may think you've gained weight, it could simply be water weight that occurs as your body goes through the natural changes of building muscle. Eventually, the water retention will resolve, so give it a little time.

Check Your Stress Levels

We've all been taught that exercise is great for stress reduction, but there is a caveat to that claim. Emotional stress is stressful to your body just as physical stress is, and if you add more high-intensity exercise to your stressed body, this can cause even more damage.

Too much stress causes your body to release stress hormones, including a nasty little hormone that causes our bodies to store fat. Make sure you're getting enough sleep, managing your stress, and doing other things to take good care of yourself.

The bottom line is, don't give up on exercise if you're not losing or if you're gaining weight.

There are many changes that take place in your body at the beginning of an exercise program, and you will need to let your body respond, recover, and grow stronger. During this time, it's the little things that usually throw people off track. That said, if you are still frustrated, what can you do?

Next Steps For Weight Loss

If you've been exercising for weeks and you're still gaining weight or you haven't seen results, you might consider hiring a personal trainer. A trainer can look at what you're doing and give you more specific advice about your exercise program as well as your diet.

In my experience, it often takes up to a year to really see significant changes in your body from exercise, and diet plays a huge role in those results as well. This is yet another reminder that you may need to take into account everything you are doing, not just your exercise program.

If you are someone who really does tend to bulk up with exercise, don't skip your lower body workouts. Instead, try sticking with lighter weights and higher reps (for example, around 12 to 16 reps) per exercise.

You can also try circuit training which focuses a bit less on straightforward weight training and more on keeping your heart rate elevated.

Bottom Line

The muscles in your buttocks will only increase in size if you lift very heavy weights (for 6 to 12 reps) or if you eat a high-calorie diet. If you're using lighter weights you don't usually need to worry about your derriere.

Very often people are frustrated because they haven't lost—or have even gained weight—when they start exercising. If this is the case for you, patience can help. It may take a while before the pounds drop off. If you are still frustrated, take a second look at your diet and make sure you are practicing stress reduction.

Some people may need to hire a personal trainer or try circuit training instead. Whatever you do, try not to give up. When you persist you're likely to get the results you want.

4 Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Handelsman DJ, Hirschberg AL, Bermon S. Circulating testosterone as the hormonal basis of sex differences in athletic performance. Endocr Rev. 2018;39(5):803-829. doi:10.1210%2Fer.2018-00020

  2. Schoenfeld BJ, Aragon AA, Wilborn CD, Krieger JW, Sonmez GT. Body composition changes associated with fasted versus non-fasted aerobic exerciseJournal of the International Society of Sports Nutrition. 2014;11(1):54. doi:10.1186/s12970-014-0054-7

  3. American Heart Association. What exercise is right for me?

  4. Yoon EJ, Kim J. Effect of body fat percentage on muscle damage induced by high-intensity eccentric exerciseInternational Journal of Environmental Research and Public Health. 2020;17(10):3476. doi:10.3390/ijerph17103476

Additional Reading
  • Jackson, M., Fatahi, F., Alabdujader, K. Jelleyman, C., Moore, J., and H. Kubis. Exercise Training and Weight Loss, Not Always a Happy Marriage: Single Blind Exercise Trials in Females with Diverse BMI. Applied Physiology, Nutrition, and Metabolism. 2017 Nov 2. (Epub ahead of print).

By Paige Waehner, CPT
Paige Waehner is a certified personal trainer, author of the "Guide to Become a Personal Trainer," and co-author of "The Buzz on Exercise & Fitness."