I’m a science teacher — I teach chemistry and physics. I love to use comics in my classes. The problems, combined with the characters and stories, can really hook my students in and increase their “engagement,” which is one of education’s huge buzzwords. I love when comic writers and artists take an extra step to keep the science accurate, or at least, somewhat believable.

But at the same time, I give a wide berth to the powers, creatures and situations. Sometimes, science won’t work at all with comics, and you just have to let it go. No amount of hand-waving will bring it back into agreement with the laws and principles we know and love in our world.

I’m totally cool with that part of it, too. As my wife (also a science teacher) and I tell other STEM teachers who want to inject pop culture into their classes, rule #1 is: Don’t Kill the Fun. Sometimes, superpowers are just magic.

Here’s a case in point. As was brought up in last week’s Panels of Purpose, the Flash told Green Arrow that he needs to eat about 50 times his own bodyweight every day to keep himself going at superspeed.

Historically, yeah – this dates back to the days of Mike Baron writing the Wally West Flash just after the original (and best) Crisis on Infinite Earths. Wally was shown scarfing down piles of hamburgers and other food in order to keep up with his metabolism, but thankfully, the science was hand-waved away and, as far as I can recall, no numbers were ever attached to it. Fine – cool. Super-speed means super-metabolism. NBD.

A recurring gag on the Justice League cartoon, too

Which brings us to Green Arrow #26. Flash needs 50 times his body weight in food in order to do what he does? If you ever find yourself writing a scene with Flash in it, don’t have him say this. Just don’t.

Why not? Because nerds (and that’s what we are) can hook on to that number and start to play with it. Like so:

If the Flash is about 170 pounds (according to the DC Universe Wiki – which, admittedly, it a little on the heavy side for a guy who runs), 50 times his body weight is 8,500 pounds of food – 4.5 tons each day. Most Westerners eat about 4 pounds of food a day, which reflects a caloric need of roughly between 2,000 and 2,500 calories (people get by with a lot less and a lot more, but we’re shooting for the average). That’s roughly 500 calories per pound of food. 4.5 tons = about 4,250,000 calories. Which is about how much a regular human needs for 5 years.

According to Flash’s statement, he eats 5 years worth of food in a day. That right there is a serious pressure on the local community he’s a part of. He’s consuming resources at a staggering rate. So, taking that as a starting point, Flash’s bonkers revelation leaves us with more questions than answers:

Time and Space

How long does it take to eat 4.5 tons of food? Large herbivores like elephants can eat up to 500-600 pounds of food a day, but it takes them a long time – like, 12-18 hours to do it. Okay, Flash would be eating (chewing, swallowing, digesting) at super speed, so he wouldn’t take all day to eat, obviously. But still … if he needs this many calories, eating would take up a somewhat significant portion of his day. Why haven’t we ever seen him eating – like seriously eating?

Takeru Kobayashi, who holds many world records for competitive eating, has eaten 110 bunless hot dogs in 10 minutes. Again, the Flash would be eating at super-speed, but Kobayashi gives us at least a benchmark for speed-eating. There are 151 calories in a hot dog, so 110 hot dogs = 16,610 calories. If Kobayashi was looking to get 4,250,000 calories by eating hot dogs alone, that’s 28,146 hot dogs. Without rest (and an infinite stomach) Kobayashi could eat those in 2,559 minutes, or 42 hours. That’s eating non-stop, and not rescuing the world.

Speed this up, and this must kind of be what the Flash looks like when he’s eating.

Also … how long does it take to prepare that much food and where does he physically store it? Sundays are cooking days for the week? Does Blue Apron send a daily truck up to his door? Wouldn’t the neighbors notice?


How much does 4.5 tons of food PER DAY cost? DC’s been working hard on the Peter Parkering of Barry Allen, making him into an everyman on a CSI salary, so where does he get the money for this?

Let’s say Barry was hating himself and wanted to get all of his calories from hot dogs for a day. As we calculated above, 28,146 hot dogs contain the calories in 50 times the Flash’s body weight. Today at Wal-Mart, an 8-pack of Nathan’s hot dogs (at 140 calories per dog, they’re slightly lower in calories than 151, but we’ll roll with it) costs $2.88.

Flash would need about 3,518 packs. $10,131.84.

That’s for one day. A year on hot dogs alone? $3.7 million dollars.


The Flash is a superhero. They get captured all the time. Heck, Barry was just shown in chains on the cover of Justice League #24. What happens when the Flash doesn’t eat? Does he whither away?

To maintain basal metabolic rate (which is what you’d be at if you were chained in a bad guy’s basement), humans need about 1,550 calories per day, on average. That’s just to keep the heart pumping, body stuff working, etc. That’s 64.6 calories per hour. The Flash’s super-metabolism would be waaaay higher than this, and thus, he’d be in dire straits if he was held captive for a couple of hours. Half a day without food? He’s dead.


Yeah. 50 times your body weight in food. Even the Flash wouldn’t metabolize and fully digest every last bit of the food he ate. For example, if there’s any cellulose in the food he eats, as a human, he can’t digest that. That’s what we call fiber and it scrubs out intestines. (Fiber is good for you –eat fiber.)

So there’s going to be waste. Heck, in the panel, Green Arrow makes a crack about it.

A normal human at about 170 lbs. poops about a pound a day. That’s a quarter of the four pounds Western people eat. If the Flash is eating 4.5 tons of food, he’d produce a little over a ton (2,125 pounds) of poop per day. Know anyone who owns a Mazda Miata? Yeah, your friend’s car weighs just a little bit more than the poop the Flash would produce daily.

I’m not going to even wonder about where it goes, the plumbing, etc. … but look: if Central City doesn’t have some plan to figure it out, and the Flash is strictly in town for say, a month fighting crime, you’ve got some water treatment problems you need to address.

Pandora’s Panel

Yeah – I went down some weird rabbit holes here (I didn’t even start to talk about how, if Barry chews at super-speed, the motion of his jaw would cause the air around it to move faster, heating up as a result, until the air around him would reach temperatures of hundreds if not thousands of degrees), but the door was opened by having the Flash say he needs to eat 50 times his body weight.

Again – if you ever write the Flash … no, just no. Don’t try to put any numbers on him. People like me will only start to play around with it and write articles like this, and people will write comments about how people like me just can’t let things like that go, and blah, blah, blah … no one wins.

Flash (vol. 2) #67

But for Green Arrow #26, there’s an easy way out. So easy, what’s probably going on (or will be retconned into having gone on once issues like this are brought up to DC editors or writers) is simple. For what, 20 years now, the Flash’s speed came from the Speed Force. Easy. What do you want the Speed Force to do? Cool – no problem, the Speed Force can do it. The Speed Force is magic. The Speed Force answers all questions – heck, I use it in my classrooms when my students ask about the physics of something they saw on The Flash TV show on CW.

So if the Speed Force is established, why have Barry say anything like that to Green Arrow?

Follow it through – Barry tells Ollie a bullshit story, Ollie believes him, and somewhere down the line, Ollie tells someone who knows better, say, Superman or Batman. Heck, maybe Ollie, in talking to Batman some day, has a reason to ask him some of the questions above. I figure it would go something like this:

Ollie: Man, I don’t know how Barry does it.

Batman: What do you mean?

Ollie: How he has to eat or die. All that food he has to find and eat every day. He’s amazing.

Batman: What are you talking about?

Ollie: (explains some of the above)

Batman: …

Ollie: What?

Batman: Just how stupid are you, Queen?

Barry was just playing Ollie by telling him he needed 50 times his body weight, thinking Ollie was stupid enough to believe him.

I hope.

(Apologies if I spoiled an upcoming Flash storyline about Central City becoming a food desert, and a new mountain of poop growing to the north of the City that becomes the base of a new, very smelly supervillain)

In addition to teaching science, Matt Brady and his wife Shari operate the website The Science Of, which looks at the science in pop culture from a STEM classroom point of view.