“How can I improve my mental health without medication?”

Don't be afraid of all medication. Medication, in some cases, helps our conditions and keeps us on track. When I grew up there were no cell phones and I had to use a pay phone. Technology gave me a cell phone. Some medications give us the same advantage. If we are not where we want to be, there is nothing wrong with using a tool to help. If I broke my arm, I wouldn't want to heal without a cast. See a good bariatrician in your area by going on www.obesitymedicine.org and they can help with or without medication.

Physical and mental health are often linking, so a healthy lifestyle can have a positive impact on mental health. Another option is to speak with a therapist or counselor. They are generally able to help people work through issues and come up with coping mechanisms.
Mental health is a complex area, and there are many variables that play into it, so talking with a provider in person regarding to bet a better idea of the specifics for you would also be beneficial.

Recognize what your flaws and insecurities are. Tackle those flaws and insecurities head on. Whether it be talking to someone (therapy), exercising, yoga, getting in touch with your spiritual side. Exercise has been proven over and over again to be the number one anti-depressant, it helps with insomnia, obesity, high blood pressure, diabetes

Being 24 and unfortunately being overweight is emotionally taxing, I am sure. You don't want to take medications and I understand that. The first thing you need to do is see a primary doctor to be tested for several issues. Hypothyroidism, Polycystic Ovarian Syndrome, Insulin resistance. Once you have accomplished that, you can start on one of several regiments. The easiest, but yet hardest is to decrease what you eat and increase your exercise. Simply walking every day, stop drinking sugar-based drinks, eating less processed foods. Those tests are very important because they can dictate what the best action will be.
I wish you well.

There are many things to do to improve mental health without medication. A diet that is low in sugar and artificial chemicals and sweeteners, plus regular exercise can make a great difference. Reducing alcohol and caffeine usage also helps. Trying meditation or yoga can help your focus and anxiety.