Spot Reducing

Fat on your body is reduced ONE main way.......................expending more calories than you consume. Doesn't matter if it's HIIT, weight lifting, cardio, etc. The thing is that you lose body fat systematically. So if you lose 1%, it comes from all over the body and not areas you try to target.

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
Kickboxing Certified Instructor
Been in fitness for 30 years and have studied kinesiology and nutrition

Are you sure it's all arm fat? Many women mis-identify relaxed triceps muscles as fat or loose skin. (I'm not saying you have zero arm fat, but suggesting you may have less than you think. Many women do.)

Raise your arm so your upper arm is above shoulder level, bend tightly at the elbow, curl the wrist toward your forearm, and tighten up everything on your arm, especially the upper back part of the arm (triceps), flexing like a bodybuilder. Get it as tight as you can. Anything that firms up is muscle, not fat.

To make it clearer, take your opposite hand, and grab the tissue of the upper arm, with your fingertips as close to the bone as you can get them, holding onto the "fat". Then do the "flex like a bodybuilder" thing as described above. If it tightens up or firms up in your hand, it isn't fat, it's muscle.

Even quite-fit women, not to mention men, have triceps muscles that are mobile (will be slack, and "flap around" if the upper arm is shaken) when the arm is relaxed. This needs to be true, because muscles contract in order to do work, which implies that they need to have a little slack in them when relaxed. The longer muscles, like those triceps, will hang down and move a little when held horizontally shaken while relaxed.