You have a strange idea of how easy it is to induce starvation in a country. To do so, you have to physically control the borders so food can't be imported. You have to destroy food stores. You have to destroy cropland, the farming labor pool one way or another, or both. You have to destroy fuel supply and production, and railroads, and most roads. Germany had starvation at the end of both world wars because of the British blockade, and the destruction of the farming labor pool by the military sucking up too many farmers. Even then it took years. The United States does not have the ability to control Iran's land borders without an invasion. Not happening. The United States has no interest in destroying Iranian cropland. It has no ability or inclination to decimate Iran's farming labor pool. With its current forces in theater, the United States does not have the ability to destroy Iran's rail and road network to a sufficient degree to induce starvation by lack of ability to distribute food. Doesn't have the inclination either. Water supply in any decently modern country is dependent on electricity, and you can be sure the United States would be careful not to limit the water supply to such a degree that people litrully start dying of dehydration
The US would need significantly more planes, and a dedicated campaign of at least a year, almost to the exclusion of hitting other targets, to kill people through starvation and dehydration. Killing people through dehydration is a lot harder than starvation too, to the point where it's unheard of outside of pre-modern sieges. Also such a campaign would awkshully be a war crime. Don't embarrass yourself again geez