There's also suspicions that artificial ingredients in food alter the body's ability to process food, leading to obesity. It wasn't just television, computers, and a "sedentary lifestyle" that led to weight gain; something changed in the food.
https://www.diabetessciencenews.com/2019-10-21-propionate-can-increase-diabetes-and-obesity-risk.html
From the article at the link: "The supposedly “safe” food ingredient [proponiate] is a potential endocrine disruptor."
Artificial ingredients are also what's likely lowering levels of testosterone in men.
What is artificial? Are people eating things that don’t already exist in nature? Not big on complaints about “processed”. Which BTW just mashing up a potatoe is “processed”. It means nothing more than changing the original state of the food. Cooking is “processing”.
There may be some chemicals used more now than originally were in most foods, and they may affect us some.
But the fact remains, some of us have very hard times losing weight, and some of us have very hard time gaining weight. I was skinny (as was most of my dad’s family…can’t that be genetic?), and as a young adult weighed about 125 lbs. I worked out trying to gain muscle and even tried eating both “good” and “bad” fatty foods afterwards. I could gain about 5lbs but when I stopped concentrating on it I’d lose that.
“Artificial ingredients are also what’s likely lowering levels of testosterone in men.”
Xenoestrogens.