Better would be to put the weight back on proportionally, with the emphasis on gaining lean muscle. To do this, you need to a good well-planned diet and exercise program. It sounds like you are on the right track with this, but consider seeing a dietician if at all possible. He or she will be able to give you more specific details about your dietary requirements. If your income allows it, consider hiring a personal trainer for a few sessions.
Studies indicate that using skilled trainers results in better goal achievement, for most people.
Finally, be sure to discuss this issue with your doctor. Diagnostic tests such as BIA can help to determine your overall body composition, and may be helpful over time to monitor progress. Also, it may be helpful to measure your testosterone level, as persons with HIV can have an inappropriately low amount of this hormone. Thyroid hormone testing would also be a good idea if you are gaining weight unexpectedly. Some HIV treatments may be associated with specific types of body composition changes, including a big belly.