Whenever I visit family in the midwest it can be a bit of a culture shock: by default you might find yourself walking a few hundred feet per day. With garages built into every house, few sidewalks and office parks/shopping centers that are only accessible by car, you have to make an explicit effort to get any exercise.
As a European who’s visited the states a few times, the portion sizes always amaze me. They are gargantuan in comparison to what I’m used to
Edit: Fun video - https://youtu.be/rg3Y3tCmBWo
The _smallest_ Burger King drink has 90ml more liquid than the _largest_ UK size
> in part because
I assume the other part is diet change from being in European countries.
In general, if you are very heavy, you can usually get away with significant calorie deficits through diet alone, as your base metabolic rate is so high. You should still be active for other health benefits, but your weight loss is best accomplished from from eating better and less. But the lighter you get, the more cardio matters, because at some point you'll start to have problems getting nutrition from not eating enough. This is especially true if you are getting shredded.
I think this is in part why there's so much conflicting advice on this. You have former fat people saying "nah, it's all diet", and you have very fit people saying "no way, it's totally cardio". They're both right, in their respective domain.
Assuming your diet (and thus your caloric intake) stayed exactly the same, burning an extra ~450 calories per day should net a loss of ~4 pounds per month. Over, say, a six-month span, that'd be roughly 20 pounds lost - easily within the bounds of "tens of pounds after several months."
Correct, but how many fat people are going to "reward" their efforts with a 450kcal treat?
Answer: Most.
On days that I go to an office, I don't (consciously) base my lunch decisions on whether I walked, took the train, or used a car service that morning, know what I mean?
Emphasis on consciously. Your leptin/ghrelin balance will do that for you, and you won't even think about it.
If they had reached some sort of "stable" level of obesity, that is if they had plateaud their weight gain naturally, then a sudden consistent 400kcal deficit would result in some change. Assuming they didn't eat more to make up for it.