# How much food would 1 man eat in a quadrillion years?

Let's say that all of mankind just suddenly vanished leaving only one person behind? Time is frozen and no food rots. No matter how much time passes the man in question does not age nor does anything else.

If all food did not rot and this man was able to access all available food in grocery stores and convenience stores as well as drug stores, the works. He was also able to eat MRE's from military bases and such.

Would this person be able to eat all the food on earth in 1 quadrillion years? Or would he not even be able to eat a fraction of it?

This person is 17 years of age, six foot tall and weighs 210 pounds.

• How relevant is it that the person is 17? After a quadrillion years he is probably a little bit older. – SE - stop firing the good guys Aug 21 '16 at 22:49
• He doesn't age, and i am trying to account for how much food a person at that age eats – Deuxz Aug 21 '16 at 22:55
• I don't know if he's immortal but Earth is going to be a frozen dead rock by then or worse. – Vincent Aug 21 '16 at 23:02
• Looks like a simple math problem. How much dies a person eat? MRE’s were mentioned so is he suppose to eat 2 or 3 of those per day? – JDługosz Aug 22 '16 at 0:13
• A quadrillion years is a really, really, really, really long time; for all practical purposes, it is practically an infinite amount of time. Given that your profile says you are in the US, I think we can assume that you meant $10^{24}$ (see Wikipedia). Compared this to the age of the universe, which is approximately $1.38 \times 10^{10}$ years. A quadrillion years thus is 14 orders of magnitude greater; the universe has only existed for about $10^{-14} \approx 0.00000000000001$ times your desired time frame. – a CVn Aug 23 '16 at 8:27

## 5 Answers

The Earth's biosphere has a mass estimated at between 1 and 4 quadrillion kg. Much of this mass is inedible: trees, microbes, soil organisms etc. Only a small fraction of of the biosphere could be considered to be "food". Maybe 0.1% of the biosphere is edible.

Each day a person eats between 1 and 2 kg of food. Over a quadrillion years the person would have to consume all the organic matter on Earth. So the short answer is: No, if time is frozen there is not enough edible stuff to support a person over a period of a quadrillion years. Perhaps there is enough to support one person for a trillion years.

This articles states that an average human consumes 35 tons of food in their lifetime. If we assuming an age of 70 for an average human that makes half a ton per year.

So you would need 500,000,000,000,000 tons (500 trillion tons) of food stored up for one human to live through a quadrillion years.

• 6e24 ÷ 5e17 is about 1 ten-thousanth the mass of the Earth. – JDługosz Aug 22 '16 at 0:17
• Anyone after something like 1000 years would just get bored of how stuff is frozen and commit suicide, also note that eating from groceries would just make you die by cancer in short time. No need for quadrillion years (unless OP want his character immortal) – GameDeveloper Aug 22 '16 at 12:58

So I can find many sources for this, so some things are reasonable guesses on my part.

Assuming nothing rots, decays, or otherwise goes bad, and all ability to create new food vanishes, estimates place our food throughput being roughly enough for 10 billion people.

How much food he'll find will depend on the season. Let's assume, to be optimistic, we doom civilization just as traditional harvest comes to a close for the Northern Hemisphere. While this wouldn't be harvest for every food item, let's assume that we caught 30% of all food product at 1 year's worth of production. The rest of food production will be between 7 days and 1 month of "human consumption" for the most part (such as grocery stores, etc), meaning that if civilization would continue, most of the normal food product around today would be either consumed or discarded between 7 days and 1 month. Let's average this to 20 days.

So the food product we have is:

(365 days of food * 0.3 + 20 days of food * 0.7 days of food) * 10 billion people.

We get to, then, 1.235 trillion man days of food. Divide by 365 and we get 3,383 million. Or less than a percent of a percent of your man's requirements for 1 quadrillion years.

• How about if we add something else to the question, "Magic". How long would this man be able to live if he was able to use magic to forcibly make plants able to grow, all be it time is frozen? All though he can only forcibly grow 10 plants a day and only half way grow them, so in turn every two days he would have fully grown 10 fully grown plants. – Deuxz Aug 21 '16 at 23:01
• Add magic: then make up whatever answer fits the story. – JDługosz Aug 22 '16 at 0:18

We already have correct answers as to the impossibility of this and how much food there actually is. However, there is another point that limits things still further:

Your lone man is not able to reach all the food that's out there. Few people can safely cross the ocean single-handed. Wildlife will reclaim parts of Central America, crossing there is going to be extremely difficult also.

To a lesser degree there will be food in isolated outposts that he is going to have difficulty reaching.

Given that our 17 year old, six foot tall male or the "man in question does not age nor does anything else." From this assumption all else follows, he will need to eat no food whatsoever. Why? You may cry!

He isn't changing or ageing or apparently undergoing any of the usual changes a normal human being might undergo. This is a world where miraculously everything is kept in a state of perfect preservation. Presumably he will only eat from habit, but considering he also won't to perform the usual comfort stops as well. In which case, eating more food might become a problem for him.

Unless, of course, he needs to consume food to provide the chemical energy needed to power his metabolism and move around. Quite possibly if he sits still and doesn't nothing this won't be an energy cost since he like everything else is perfectly preserved.

But calculations in other answers reveal his consumption of food over a quadrillion years will vastly outweight his needs. This little problem might be resolved not so much by growing more food or importing it from other universes, but as a beneficial side-effect of the perfect preservation process (PPP).

If the PPP not only preserves the food (and everything else) it also is capable of restoring matter and objects back to the way they were after being affected by an uncontrollable change event. For example, having a meteorite crash into a warehouse full of food or a 17 year old, six foot male eat it. The PPP will restore the food filled warehouse back to being a food filled warehouse and not a large crater. Ditto for the food the 17 year old immortal shoves down his gullet.

This does mean it is now irrelevant how much he eats, because there will always be food around for him to eat. Also, he doesn't need to rove around the planet looking for food.

• maybe he does not have to eat but he will still have a feeling of hunger, and if you have a bad feeling which does not kill you, you will try to get rid of it. – if-trubite Aug 22 '16 at 7:26
• @if-trubite This depends. When he was immortalized and preserved if he had a full stomach, then he wouldn't get hungry. If he hadn't eaten for a long time prior to his immortalization, then he could be permanently hungry and eating might not make any difference. We have so experience with immortals, hungry or not, so it's hard to tell. – a4android Aug 22 '16 at 8:38