I had asked for some further information and have not heard back.
If you are having no other symptoms, then the most common cause of bloating without weight gain would be from excessive gas, most often because of difficulty in passing the gas through the gut. The usual approach would be to use medicines to relieve the gas. The most readily available is simethicone, which is available in numerous over the counter products. Some people do better with activated charcoal, which is more active lower in the GI tract, such as in CharcoCaps. It also may help to promote the growth of healthy germs in the gut, such as by eating yogurt with an active culture or a probiotic supplement.
If you are having other symptoms, then there may be other interventions, depending upon what symptoms are present. I specifically noted constipation because it is possible for the spironolactone to cause constipation. Spironolactone is a diuretic that is used for acne because it also has activity in blocking the androgen/male effect of hormones, even the hormones that are at lower levels in women. If used because of the anti-androgen effect, it is still a diuretic, so can cause a chronic mild level of dehydration. When there is dehydration, the body will then try to hold onto fluids in other locations, including the colon absorbing more water out of the stool, which can cause constipation. If this happens, it would be reasonable to be drinking more fluids. When spironolactone is used because of its diuretic properties, it is frequently necessary to also restrict oral fluids, so you may find such instructions for people taking the drug, but this recommendation is not an issue when the spironolactone is used for its anti-androgen properties.
If I can provide any additional information, please let me know.