Liposuction - I am around 20 pounds overweight.

If you are overweight, you should first lose as much weight as you can before considering liposuction. Liposuction is a body-contouring technique that is only meant to treat stubborn fat that does not respond to diet and exercise. It can't be used as a weight-loss technique. Once you are at or near your ideal weight, if you still have pockets of fat on your arms and good-quality skin, you may be a candidate for liposuction. You may also want to consider noninvasive fat-elimination techniques, such as Vanquish, CoolSculpting and ThermiTight. The last would be especially useful if your skin is at all lax. Please consult a board-certified dermatologist to be evaluated for the best fat-elimination technique once you've reached a more stable weight.

You are a good candidate for liposuction if you have stubborn fat deposits that have not responded to diet and exercise.  I would recommend having a consultation with a board certified plastic surgeon when you are at or near your goal weight.

If you can realistically lose the weight, then that's what you should do first, or at least be within 5% of your goal BMI (or goal body weight).  

If you plan on losing the 20 lbs then you might want to wait to have the liposuction of the arms until that time.

Very few patients at their ideal weight express an interest in liposuction so it is not uncommon to see patients who feel that they are 20-50 lbs heavier than they would like to be. While I recommend that patients try to achieve and maintain an ideal weight before surgery, having a stable weight over time is the most important. The closer that you can get to your ideal weight, the happier you will be with your result. For someone truly 20 lbs above their ideal weight, a contouring procedure would likely give good results. It is important to remember that liposuction is not a weight loss surgery and should not be performed for that express purpose alone. 

When considering any kind of cosmetic surgery, it is always best to be at a maintainable goal weight before scheduling your surgery. Not only can it make the surgery safer because you are in better health, but if you were to lose or gain weight after your surgery, it can adversely affect your results. Hope this helps.