How much toast would She

THE superheroes do superhero stuff: they jump, hit, run very fast and sometimes throw rays from their eyes. As with humans, these activities require energy. Getting up in the morning takes energy. Walking requires energy. Running a kilometer takes even more energy, but not as much energy as it takes to fly a human-powered helicopter for a minute (yes, it actually happened). If even superheroes get their energy from food, how much they should eat to be able to do all the amazing things they have shown us on small and large screens?

Taking a cue from the recent release of the series She Hulk – Attorney at Lawcurrently available on Disney +, I decided to focus on the abilities of the Hulk and his female version, assuming that the two derive their energy from food. In a clip from the series we see Hulk (scientist Bruce Banner’s alter ego) explaining to She-Hulk (his cousin, Jennifer Walters) that they can drink all the alcohol they want thanks to their accelerated metabolism, implicitly confirming that their energy comes from food and not from some strange physical mechanism or supernatural source.


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Food energy

The energy provided by food is measured in terms of calories. The wrapper of a chocolate bar, for example, may indicate that a serving contains two hundred calories. However, there is one difference between how nutritionists and physicists talk about calories. From the point of view of physics, a calorie is the amount of energy needed to raise the temperature of a gram of water by one degree. A food calorie has a different definition. In fact, food labels report the data in terms of kilocalories, which means that a bar of two hundred calories is actually equivalent to two hundred times a thousand calories, or two hundred thousand calories. This distinction creates confusion.

To tell the truth, we physicists don’t like to use any of these units of measurement. We prefer to resort to joule, where one joule equals the energy needed to impress a newton of force over a distance of one meter. Lifting a book off the floor and placing it on a table takes about ten joules of energy. A dietary calorie, on the other hand, is more or less equivalent to 4,184 joules. To simplify things, I think it’s better invent our own unit of measurement of energy. We will call her Pbj, to denote the unit of energy provided by peanut butter and jam toast. It’s the amount of energy you get from eating one of these American snacks (peanut butter and jelly sandwichin fact, from which Pbj), equal to about 380 food calories or 1.59 million joules. We will use PBJs to calculate the energy consumption of superhero actions in terms of toast.

The energy needed at rest

Just staying alive requires energy – we need it to breathe, pump blood, or just blink. The amount of energy needed to survive is called basal metabolic rateor Mb. An average human being usually has an MB of about 1500-2000 food calories per day. By converting it into the energy unit we have invented, a person consumes about four or five Pbj days. The value of Bm varies according to a person’s age, weight and height. However, considering that the Hulk and She-Hulk are not medium-sized humans, they will not have a normal Mb. First, therefore, we must find out their weight and height.

How much toast would She-Hulk need to survive?