To do,.to possess or to accomplish something, you should answer the following questions in affirmative:
1. Are you really determined to do it?
2. Do you a regular time or schedule?
3. Are you willing to sacrifice your time and effort without second thought?
4. Are you all out to sacrifice, anything in connection with your project realization?
5. Are you consistent in pursuing it?
These things like determination, schedule, time and effort, sacrifice, and consistency are the effective key factors to a success whatever you may do in your life.
I'm for sure you can have an optimal belly size. And remember it's too personal.