photohiker wrote:I'm seeing a lot of theories here about nutrition and explanations of weight gains and loss, but also a lot of tip-toeing around GPSGuided's repeated "Elephant in the Room":
weight loss is all about will power. Eat less and exercise more for negative caloric balance and its all solved.
Do we agree on this, if not why not?
This is undeniably true. However, it is also grossly simplistic, and not of much value in isolation.
Some high calorie sources (in particular sucrose, which is half fructose) seriously messes with human metabolism in a number of dangerous ways, as mentioned by OSM earlier. In particular, of interest to weight loss, it actually disables a persons normal ability to feel 'full' when they've eaten enough calories. Therefore it makes it exceedingly difficult for a person to eat only a small amount (less than they are using) and hence they are more likely to put on weight when getting calories from such a source.
I think this is what OSM was referring to in that not all calories are equal. Yes, they are equal in the sense that calories in < calories out = weight loss, but some calorie sources make this nigh on impossible to achieve, and have many other serious health problems along the way. Eg, Type II diabetes is seriously exacerbated by sugar (fructose/sucrose in particular) more so than just carbs in general (at least that's one of the current theories - I'm not expert, so I don't really know).
It's also worth noting that exercise does much, much less towards weight loss than most people think. Diet is an exponentially bigger factor. Although given the way that the fad of weight loss TV shows focus on exercise, you could forgive people for thinking otherwise. I guess 30 minutes of watching people not eating is not as interesting as 30 minutes of people doing bizarre exercise regimes while being screamed at by somebody in cammo clothing.
Of course people should still exercise. It does still help with calorie burning, but has way more important benefits than that!