From obesity researcher Travis Saunders comes this excellent post on how Canadian public health efforts to increase activity work against their own aims by tying exercise with weight loss:
[T]he average weight loss in response to a moderate increase in physical activity levels is very modest, and it’s likely that many people would see no weight reduction of any kind. Even if it’s in the range of 5% of body weight (which is unlikely over the long-term), it’s probably substantially less than most people are hoping for. In which case the individuals who are only exercising for the sake of losing weight are going to get discouraged pretty quickly [...]
Further, this overwhelming focus on the relationship between inactivity and obesity may lead some lean individuals to conclude that they have no reason to be physically active since their body weight is already in a normal range. [...]
[A] single session of aerobic exercise results in measurable improvements triglyceride levels, HDL (good) cholesterol, and insulin sensitivity, even though it has no real impact on adiposity. Further, it has been noted that mortality levels are lower among obese but fit individuals, as compared to lean but unfit individuals, suggesting that we really do need to be promoting physical activity as a healthy behaviour for everyone, not just those who are overweight or obese.
Travis writes at the Obesity Panacea blog. Obesity Panacea focuses on the science (or lack thereof) behind popular weight loss products and discussions of the latest news and research regarding obesity, nutrition and physical activity. It isn’t an explicitly size-acceptance space.
[Bolding and links within the quote are from the original.]