Can I lose weight to reduce my breast size?

You are already at a normal weight with
a BMI of 23.8. Losing more weight would be a unhealthy option. If your breasts
are still large, then a breast reduction is what you need. While it is very
understandable to avoid surgery, a breast reduction is almost universally
successful with high patient satisfaction rates. You will need a week off work
to recover, but after that, you will feel better and not have the burden of the
weight of your breasts transferred to your shoulder and neck from the bra
straps not to mention better proportion with easier choice in clothing.

Your breast is made up of two types of tissue. Breast Glands and Fat. When you are young the Breast Glandular tissue is in abundance ( in anticipation of pregnancy and breast feeding), as you get older the proportion of fat increases. You may reduce the breast size if you lose weight, but it may not be enough. It will also make your breasts look saggy as you have indicated  your current size is s 12 E. I tell my patients that once they get to their 'ideal weight' to come in and have a consult with me. A one to one assessment and examination by a Plastic Surgeon will help you in your decision making process.I suspect that you will be better off with a Reduction and Lift to improve your shape.Hope this helps

Certainly breasts often consist of a mix of breast tissue and fatty tissue.  If you are overweight, it is common for the breasts to become a bit smaller with weight loss but it is hard to predict.