People don't understand how others get bigger.
Yourself included.
When they got home, they didn't have the strength left to cook a proper balanced meal.
Strength left? Utter bollocks. You can prepare and cook a nutritious, healthy, family meal in 20 minutes. What you've described is an excuse to not cook your own food, not a reason.
Sometimes it's simply just genetic.
For maybe 0.0001% of the population. Unless people have a specific medical condition, syndrome or disease, this is another frequent excuse that has no baring on reality. Maybe 30+ years ago, if you saw some obese in public, chances are they would have had compounding medical reasons why they were fat. But not today. There aren't hundreds of millions of obese people because they've got special fat genes that have just started appearing in humans.
An important point that you haven't mentioned, which is a genuine cause of obesity, rather than another excuse, is
food poverty. This is when access to healthy, non fattening food is either not readily available where someone lives, or not affordable. The foods that cause obesity are cheap to produce and cheap to buy. In some areas, that is all that's available to buy.
As I've been banging on about in this thread, the primary cause of obesity is *what* people eat. Not laziness, not gluttony, but foods that fuck with the body's chemistry and make you fat.
Another point is the spread of childhood obesity. Apart from the health impact to the kids, this has the knock on effect that a generation of people can have lived their entire life, not knowing what it's like to be a normal weight. You see a fat teenager, and to just dismiss them as lazy ignores that fact that they have not been in control over their diet. The fault of their size lies entirely with their parents. But then, you have to look within the context of the socio-economic standing of the family and whether food poverty is the underlying cause.
There have been studies that show different results, so I take that one web article with a pinch of salt. Not to mention, you can raise your metabolism through exercise and increasing muscle mass.
Can you imagine eating 20% less than you are now to not gain weight?
Even if the above were true, you wouldn't have to *eat* 20% less, you'd have to consume 20% fewer calories. That's an important distinction. Not all foods have the same calorific density. The high carb, obesity forming foods all are calorifically dense foods. You can eat more
food, yet consume fewer
calories, by changing what you eat.
That's the whole point behind low card, high protein/high fat diets. You can eat until you're physically full, the food will trigger the correct hormonal response that tells your brain when you're hungry, and yet, you'll have consumed fewer calories than eating a similar sized, carb based meal. Anecdotally, I have never encountered anyone who eats a lower carb, higher protein & fat diet and not see success in losing and/or maintaining weight. While at the same time, not feeling constantly hungry, and having consistent energy levels as their blood sugar levels aren't spiking and crashing.