Aquaman is one of the fastest swimmers in the ocean. He chases German U-boats, out-swims dolphins, can even catch up to a torpedo. The Justice League reports that Aquaman can swim at 10,000 feet per second. 10,000 feet per second is more than 3 kilometers per second, or 6,800 miles per hour. We’re talking Superman speeds, here. For comparison, Olympic swimmer Michael Phelps can sustain a speed of 4.7 miles per hour. To maintain that pace, Phelps burns about 1,000 calories per hour while racing, up to about 6,000 calories a day. If Aquaman were to spend an hour swimming at full speed, he would burn 1.4 million calories. Even to survive a day strolling at a leisurely 10 miles per hour, enough to travel from Beaufort, North Carolina to Bermuda in about 3 days, Aquaman would need to burn 48,000 calories a day.
Tuna contain a hearty 1440 Calories per kilogram, so Aquaman could get away with eating a bit more than 33 kilos of tuna per day. Unfortunately, tuna are fast. Aquaman would have to burn even more energy chasing them down. And that’s assuming he wants to eat a dense, energy rich fish. Knowing Aquaman, he probably understands tuna over-fishing better than most. Odds are, our hero is eating from the bottom of the food chain. Actually, Aquaman may not have a choice in the matter because, as the ocean acidifies, the enamel in his teeth will literally begin to dissolve. Since he won’t be digging his pearly whites into anything substantial, it looks like plankton soup is on the menu. This means that, just to stay alive (let alone do battle with the Legion of Doom), Aquaman must eat pretty much continuously.