It doesn't seem physically possible for most adult men to consume 13 pounds of potatoes a day. I'm a large man and I think I'd burst or vomit before choking down that much, regardless of how hard I'd been working. Most likely that number is just wrong.
Obviously it's possible for an active man to expend ~4500 kcal/day. I've done it myself many times. Even back during the Civil War, US soldiers typically consumed more energy dense food and only got a fraction of their calories from potatoes.
Presumably you aren't doing hard manual labor every day.
A Russian and American soldier meet during some peacekeeping mission/veteran fair and discuss which army is better.
They go through weapons, the American really likes AK-47. They talk about training. They discuss the distributed vs centralized command.
Finally the American says that they eat 5k calories per day. The Russian suddenly jumps up, points his finger at the American and starts yelling: "Liar! Nobody can eat that much potatoes!"
Seriously guys, get out your scale and weigh 13 pounds of potatoes. Could you really consume that much volume in a day without feeling sick? Let's do a reality check here.
A week prior, I ran out of food in the mountains. I finally got to a store, bought a loaf of bread, a pack of Oscar-Meyer bologna, a pack of cheese slices, two sodas, and a red bull. When I left the bench near the store, I had a few slices of bread left.
When you put out incredible amounts of energy, you can eat a fairly incredible amount of food. I don't understand where the food goes, it really doesn't feel like you should be able to eat that much volume but you can.
Yes my examples were somewhat high energy density but in the second example, I probably had 3L+ in my belly in just one meal. Honestly I think your body just gets used to it.
I'm not familiar with the 13 lb of potato claim, but it strikes me as a stretch (hah!) but not inherently implausible.
There's the difference.
Once you spend every single day doing hard manual labor for years consuming potatoes for the majority of your calories then tell me 13 pounds is impossible.
Sure, its impossible for you now, but that's totally irrelevant. An equivalent statement would be "it's totally impossible for a human to throw a baseball at 90mph, I tried for a whole week once and I only threw 40mph."
For some activities there is a skill and technique aspect which impacts the amount of energy required. Like if a keyboard jockey literally doesn't know how to swing a pickaxe effectively then they're going to burn more calories digging a ditch compared to someone who's been doing it for years.
https://www.scientificamerican.com/article/the-exercise-para...
That's not what recent research indicates. The author has written a book about this as well.
It's the key evidence behind the idea that you can't outrun your fork. To lose weight diet is the only way. Exercise gives you a nicer-looking, stronger body but it can't do much to make you shed fat.