I want to get rid of arm fat, what can I do and what is the most effective way to diet?

Eat healthy. A combination of reduced calorie intake and exercise will generally produce the results you are after. Weight watchers is an effective program if you are consistent with it. It's just an organized way of having smart eating habits. Once you are at your ideal weight and the arm fat remains, liposuction can be considered as a treatment option. It is best to consult a plastic surgeon to see if surger.
Spot fat loss does. Not occur naturally. By losing weight in general a certain amt will be arm fat. Eat healthfully ; be physically active. Calories burned must > calories consumed. Tone arms w standing biceps curl w dumbbells, hammer curls w dumbbells, triceps kickback w dumbbells ; lying triceps extension w dumbbells.