Let's cut the writers some slack, it would be boring if any movie or show included too much everyday stuff like sleeping and eating, even though that's what people realistically spend most of their time doing. But some good entertainment does take a moment to acknowledge the necessity of super nutrition. For example, the Justice League cartoon frequently makes references to the Flash's abilities to eat as fast as he can do everything else.
Now I’m going to add some calculations of my own modeled after the summer blockbuster Iron Man 3. One of the biggest factual holes in the plot was how the Extremis villains were capable of regenerating so quickly AND having enough energy to create searing heat on top of that. Sure, all cellular work has some waste energy lost as heat, but this is ridiculous! The example easiest to calculate for is the scene where Aldrich Killian forces Colonel Rhodes out of the Iron Patriot suit by heating it up.
The last calculation I'll make is purely for fun: what if Rhodey's suit was hilariously made up of Rhodium? This would be a poor choice as it's a less sturdy metal. It's specific heat is only 0.058 kcal/kg/°C, but with a melting point at 1,963°C there's some distance to cover. The total comes to 1,690 Calories, so at least that's within range for normal human consumption. The main point is that a whole day's worth of food is burned up in a few minutes, and then these guys keep doing even more extraordinary fire acts throughout the movie! It's just not feasible without them refueling in between every superheated punch.
- Become a wet blanket during action movies and point out to all the other viewers the energetic inconsistencies of superpowers.
- Play games like "Where's the food?" and imagine how hungry the superhumans are getting.
For example, when Captain American is feeling down in his eponymous film after losing his good friend Bucky, he hides himself in the rubble of a former bar and fails to drink his worries away because he metabolizes the alcohol too fast to feel the effects. I like to imagine that he only turned to liquor after rummaging around for abandoned food to satisfy his unending hunger!