I would contend that physical activity is probably not a large determinant of weight, although physical activity is an important determinant of health.
Yes and no.. on a strict thermodynamics basis, it's not. If you're say 30lbs overweight (i.e. some, but not much), straight up burning that is going to require considerable patience and discipline to not destroy your body in the process. Each lb of fat is - very roughly - equivalent to running a marathon.
However, being physically active makes you more aware and mindful of the input side of the equation; building muscle mass, cardiovascular fitness and endurance in turn improves your metabolic ability to burn calories. So it's absolutely part of the picture. "The Miracle Pill" by Peter Walker is an excellent introduction to the topic.
However, being physically active makes you more aware and mindful of the input side of the equation; building muscle mass, cardiovascular fitness and endurance in turn improves your metabolic ability to burn calories. So it's absolutely part of the picture. "The Miracle Pill" by Peter Walker is an excellent introduction to the topic.