It's not that we lack self-discipline or willpower to be successful. The problem is that dieting couldn't be more opposite to how we're evolutionarily designed to survive and function best. Could you ever imagine our distant ancestors going against their biological drive for survival by purposefully eating less food when it was available?
I've been around the dieting block a couple of times myself. OK, more than a couple. Right now, I'm in that unenviable spot of having no clothes that fit comfortably while I'm in a stare-down contest with summer. Who's going to blink first: My need to lose my winter poundage or that bathing suit I won't wear unless I do?