In fact, people who ONLY eat red meat will find it LITERALLY IMPOSSIBLE to be overweight.
Try eating only steak, eggs, and sardines for a year and then check the state of your six-pack abs if you’re curious.
This is such an absurd statement. There's many factors around gaining weight, but it all boils down to simple how many calories you spent vs how much you eat. There's no magical "eat however much you want" diet that it's impossible to gain weight on
But you wouldn’t be the first one to tell me I’m wrong without actually trying the diet and seeing for yourself whether you gain or lose weight on it.
Also, consider the fact that some calories will result in hormonal signals in your body that increase your hunger, whereas other calories will result in hormonal signals that decrease your hunger.
Your body needs nutrients, not just calories — that’s why we can’t just drink gasoline and call it a day.
Actually, that’s a good question for you — why is it that people can’t just drink gasoline, since it contains calories?
Do you think a person would gain weight if they only drank gasoline and didn’t exercise enough? Do you think a person would feel hungry again just a couple hours after drinking some gasoline?
Incidentally, when it comes to health, weight gain and weight loss are of relatively minor importance compared to body composition. Gaining weight in your musculoskeletal system is a good for survivability and quality of life! Denser muscles and bones are not a bad thing. It's excess body fat, in particular visceral body fat, that causes morbidity and mortality. If you get fat enough your body will start storing those lipids in your vital organs, and that's a recipe for inflammation, early cancer, and other kinds of death.
Edit: here’s a fun story about a normal guy trying a high protein diet: https://fivethirtyeight.com/features/the-rock-dwayne-johnson...
Also, I render my own tallow from beef suet and often add it to ground beef. I also slow-cook roasts in tallow.