How can I lean out and build/maintain size in my upper body at the same time?

[Jax81]

I've started running (although I hate it) because I really want to lose my jiggle butt. My upper body was making great progress but since I've been running I've lost size in my arms. Diet hasn't changed much- little more carbs and plenty of protein.

I we spending 85 percent of my gym time with weights but I was getting a bit too bulky. Now with more of a 50/50 split, I am leaner but losing size.

How can I keep building size while staying lean? Feels like a bit of a yo yo effect. Thanks for any suggestions

[MrB1g]

Honestly? Keep the caloric surplus small.

However you juggle cardiovascular exercise and diet, it will always come back to that. Simplicity is both great and frustrating!

[rorschachsaysno]

If you want to lose fat in one place you're going to lose it in your upper body too. The size you'll lose in your upper body will be fat if you keep your macros in check. If you want to lose the jiggly butt, either lose fat or build muscle in the glutes (squats, lunges, leg press). If you build muscles, your butt might get bigger but it won't be as jiggly since the fat cells will spread out on your bigger butt. That is, if your bodyfat % doesn't change..

[megdaig]

You likely lost size in your arms because you had more fat covering your muscle than you realized. We are always quick to say we're getting too bulky because we've gained a lot of muscle when in reality we just underestimate how much fat we truly carry. You don't build muscle on a deficit and maintaining 100% of your muscle on a deficit just isn't going to happen. This is where bulking and cutting cycles can help.

Like MrB1g recommended, the least you should be doing is maintaining a slight caloric surplus. You look tiny to begin with so gaining a few pounds of muscle would help you look a lot leaner than continuing to diet down.

[billb7581]

I'd ask Rowyn LOL...