The upper class (doctors, lawyers) consumed more food then the working class because they could afford it, yet there was no obesity.
It's not about calories.
It's not about sugar.
It's the PUFAs making us fatigued and sick.
PUFAs are the evolutionary signal for the coming winter and they reduce our metabolic rate which ultimately leads to sickness.
All mammals seek PUFAs when they want to go into hibernation and if you give them a PUFA free diet they will burn through their fat-stores within days.
Listen to this for the quote in the subject: https://youtu.be/QmNzV15Wads?list=PL_7Y5WbwJV_uFMcCRNFbEhmEfV9bLyw2m&t=2142
Then listen to the whole conversation or start at 24:40 to skip the first topic which is specifically about kids.
There are two great channels: "David Gornosksi Fan Favorites" and also "Danny Roddy".
These are the people they have lot's of conversations with:
Brad Marshall (Ex-Keto. Cook, Pigfarmer, Geneticist.) https://fireinabottle.net/
Dr. Ray Peat (Ph.D. in Biology) http://raypeat.com/
Georgie Dinkov http://haidut.me/
Don't worry, when i listen to these guys don't understand most of it either.
The worst PUFA offenders are sunflower oil and corn oil (see https://fireinabottle.net/lets-talk-about-fat/ in the middle of the article).
Listen to this part again: https://youtu.be/QmNzV15Wads?list=PL_7Y5WbwJV_uFMcCRNFbEhmEfV9bLyw2m&t=2387
I know it sounds weird, i did keto and carnivore for the last 10 years.
Note however that today the feed of pigs and chicken is high PUFA (corn) and therefore the best choice would be ruminant meat. Some say it's not a big deal or they eat leaner meat and add butter or tallow.
Thank you I really appreciate your insight.