I was cooking out the other day and placed a different brand name of aluminum foil in the grill and when the charcoal was burning, I noticed a different smell.
I think fumes from any burning thing are probably not goodBut unless you are breathing deeply, or burning it a lot, I wouldn't worry about itBurning aluminum is going to smell differentmake sure the brand you were using doesn't have some sort of non-stick, or special coating, but in general, all aluminum foil is the same.
Not exactlyYour body does do some adjusting if you are consistent with the amount of calories you consume from day to dayThat's why some diet plans adjust your calories every few days so it doesn't get used to a certain amountBut it doesn't adjust so that it burns off all the calories you consumeActually, it's almost the oppositeIf your calorie intake is consistent from day to day, your body gets used to that and thinks that's what you need to survive and doesn't really start burning calories until after you reach your normal consumption levelOf course, you can always change the amount of calories you burn through exerciseAlso some diet plans suggest that certain foods jump start the metabolism to help you burn calories more efficiently but I don't think it's the calorie count that determines this.
