There is more to health than just the physical. A person needs to have a healthy mindset in order to live a healthy life. If you hate your body there is nothing you can do, losing or gaining, that will make you love it. You will need to have a healthy body image along with trying to keep your physical body healthy.
Try not to (I say try because doing so could be hard for some) but try not to base your body and your beauty on others. Some people are naturally thinner, some naturally curvier and others are somewhere in the middle ground. There is nothing wrong with any of those diverse shapes. The issue comes in with eating healthy, staying active and doing your best to keep your body healthy. Healthy is a compilation of mental health and physical health.
Read more information on body image here: Body Image
Below is a standing workout for abs if you are looking for one to add to your routine.