Are we meant to have flat stomachs? because all the diagrams of the human body show a very lean figure with the internal organs inside of? thin=ideal?

Body weight/physique: Being overweight or obese is not healthy. It raises the risk for diabetes, heart disease and even some cancers. Ideal body weight depends on your height, & you can find charts online called BMI charts to help you find your ideal weight range. We all need some fat on our bodies to keep warm and to allow our body systems to work properly. But too much fat especially around the abdomen is unhealthy.