What Causes Weight Loss in the Buttocks Area?

Have you ever looked at your backside in the fitting room mirror and thought, "Oh no — I have somehow developed an old man butt!" Unexplained weight loss in the buttocks area can be frustrating, especially as we age, but it all boils down to one basic concept: if you don't use it, you lose it.

"But where did my butt go?" Unexplained weight loss in the buttocks area is quite common for two main reasons. The first is that loss of muscle mass is simply part of the aging process. According to Harvard Health Publishing, age-related muscle loss, called sarcopenia, causes you to lose as much as 3 to 5 percent of your muscle mass per decade after age 30. In fact, most men lose about 30 percent of their muscle mass during their lifetime, and this may partially be due to a decline in testosterone levels.

The second reason our butt seems to shrink or become more flat over time is that the gluteal muscles, just like any other muscles in the body, require regular strength training to build, and in this case, maintain. The American Heart Association recommends doing moderate to high intensity muscle-strengthening activities on at least two days per week.This can be especially relevant, as many people gravitate toward upper body movements like bicep curls and chest presses or ab exercises like crunches and planks in a gym setting.

It's important to note that all muscles — both upper and lower body — require regular consistent work to maintain, as well as regular aerobic activity. If you think you can completely overhaul one specific area of your body (like the glutes) without impacting other areas of the body, think again. This is because the concept of spot reduction, or the idea that you can lose weight in just one area of your body by doing targeted strength exercises, is a myth. But the good news is that if you work to improve your overall physique and keep up with a routine, you will notice a positive improvement across the board.

Read more: How To Build Muscle Mass After 50

There are many great exercises out there that target the glutes, and you can build muscle at any age.

Move 1: Air Squats

All you need is body weight for this glute-building exercise.

1. Start standing with your feet hip distance apart and your arms extended straight forward.
2. With the majority of weight in your heels, bend at the knee as you push your butt far back while keeping your chest tall and proud.
3. Lower down as if you are trying to sit in a really low chair, but be mindful to make sure your knees aren't protruding beyond your ankles. This will help protect your knees from injury.
4. Stop when your thighs become parallel with the floor and then drive through your heels to stand up again.
5. Repeat until your reach fatigue or for a designated interval time.

Move 2: Kickbacks

This exercise can be performed with body weight alone, too.

1. Start on all fours with your wrists below your shoulders and your knees below your hips.
2. Either stay on your hands or drop down to your elbows if you prefer.
3. Keeping your hips square to the ground and your knees bent at a 90-degree angle, lift your right foot toward the sky as though you are stamping the bottom of your shoe on the ceiling. Squeeze through your glutes to lift.
4. Lower down in the same fashion and repeat. Switch to the left side after reaching fatigue on the right side.

Read more: Deadlifts for a Bigger Butt

If you are experiencing muscle loss in the buttocks region (or anywhere else for that matter), it may also have something to do with your diet. According to the Academy of Nutrition and Dietetics, protein should take up 10 to 35 percent of your total calories for adults if you are trying to build muscle with exercise. If your goal is just to maintain muscle mass, less is required. The academy recommends that a 150-pound adult should aim for approximately 56 grams of protein per day to maintain muscle mass.

If your mind is going straight to chicken or fish when you think of protein, you're right — but meat isn't the only way to get it. Beans, whole grains, eggs, nuts and cottage cheese are also viable options, as well as many others. In fact, those looking to eat a plant-based diet exclusively should have no problem reaching their protein intake goals for the day.

Read more: Soy Protein Vs. Meat Protein