For weight loss I just do a bit of calorie counting for a while and for me it works well - although I'm only looking to lose maybe 10 lbs max for some specific climbing events. But it always surprises me how many calories we consume without really being aware. If I count calories for a few weeks I can adjust my intake and drop those 10 lbs over the course of a few months. I agree with others who say diet is way more important than exercise for weight control. Although ultimately it all works together for a healthy lifestyle.