High protein low carbs is the first diet change you need to lose weight in your arms. Unfortunately you normally need to lose weight in your entire body to start effecting your arms. High protein will build more muscle to burn off more fat and carbs that lead to saggy arms.
Cardio is another help to lose weight in your arms. Performing some high intense cardio exercise 30 minutes a day 3-4 days a week will help tone the arms and drop the weight. I would recommended power walking with weights in hand for those new to exercise methods.
Weight training will also be helpful to burn off the fat and lose weight in your arms. Notice I said you need to burn off the fat.
This is a fact *you can not turn fat into muscle or muscle into fat.* As you build muscle the fat is burned off and the protein you consume helps create muscle. Don't ever let anyone tell you different!
The reason muscular people can eat more without gaining weight is because they have a bigger engine that can burn fuel faster so start hitting the weights and enjoy the perks.
To keep motivated you can join look at several large fitness magazines.
Weights can focus to build muscle in your arms to burn off more fat and the diet can reduce your incoming fat/carbs so you have less coming in to take care of
Try push-ups to further tone your arms and build muscle. Lay face down on the floor. Push your body up several inches off the floor with your hands. Keep your spine straight. Repeat about five times for a beginner. Work your way up to about 30 push-ups every other day.
Keep hydrated by drinking at least eight cups of water each day. This is important for losing weight in your arms because drinking enough water helps you lose weight quicker and will give you more energy to exercise. Water also nourishes the skin so it stays firm and does not lose elasticity as you lose excess weight