I don’t even understand the reason the question is being asked.
Let me reformulate the question slightly:
“Imagine I and Mindii sat in a Barcalounger, watching Judge Judy and eating bonbons for half an hour. Which one of us experienced more physical exertion?”
In terms of work, lifting a 50-lb turkey drumstick of an arm to convey a bonbon to the mouth is probably significantly more work than lifting one of Mindii’s ‘hot wing’ matchstick arms. However, if Mindii is truly buff (and not just skinny) her trained muscles would have a higher metabolic rate than the hypothertical snoopyfan’s sedentary, nay, near comatose, muscles (‘hypothetical snoopyfan’ because, as we all well know, the real snoopyfan is lithe and svelte)
Mindii might well be burning more calories than her 20-lb heavier mother, Mindi  watching the same show, eating the same bonbon - and she’s less likely to gain weight doing so. However, if the difference were much more substantial, her mother would likely be burning more calories.
Weight gain/loss and fitness are more complicated than mere calories. For example, as a child I calculated that the calories in the sanck chips I ate when I wasn’t really hungry added up to more than my total body weight (I was a skinny kid). It would seem that without those totally superfluous snacks, I would have long since died - but clearly this isn’t true. In fact, if you add up the lifetime of superfluous snacks eaten by a typical overweight American, you might be tempted to believe we’d all be dead without junk food.
(No criticism of the overweight intended. It’s just that after man yyears of study of biochemistry, including degrees in moleculkar biology and medicine, I feel calorie counting is ridiculously simplistic, and ignores effectively all the relevant control mechanisms that lead to anything but minor weight gain or loss. In a century, it’ll probably sound like those Victorian copper bracelets and magnetis therapies)
 For those unfamiliar with the naming coinventions of the buff gymbunny: the additional i’s are akin to the Roman numerals used by royalty (which some gymbunnies feel they are), Properly, the sequence is Mindy begets Mindi (start of a dynasty) begets Mindi with a heart over the i, who only properly becomes Mindii when she has a child of her own (Mindiii), but many a buff gymbunny hurries the progression in an excess of maternal ambition, which backfires when the stressed child discovers Jerry Springer, Bonbons and Barcaloungers. The proper progression of the i’s does however, continue even if the child is not named after the mother: i.e. Mindii may beget a girl Cindiii or a boy Samiii