If I eat mainly sugar and starches I can easily wolf down 4000 calories a day. If I eat a low carb diet it's a struggle to eat 2000 calories a day, the feeling of hunger isn't the growl in my stomach but a kind of mild headache, and after a couple of days my cravings for sugar subsides. The idea that some foods are more "satiating" than others is important, and involves many factors from calorie density to palatability.
Our bodies also regulate our desires for energy input and output. If I am depressed, exhausted or do not get enough sleep I will crave carbohydrates. If I eat certain foods I will feel lethargic and be more inclined to sink into the couch for the evening.
"Eat less, move more" to lose weight is true, but not useful. How you encourage people to do that that is the domain of biology and psychology, not physics.
A human body is a mechanical system.
Fuel + air in --> Work done + waste out.
That's it. Any other argument is literally disputing the laws of thermodynamics.