IMHO, the source of the calories IN has no bearing on the issue (barring disease processes, such as diabetes). You CAN lose weight on 3 chocolate bars a day. And if you eat one apple a day over your maintenance caloric intake, you WILL gain weight.
There is no doubt that you will feel FULLER and your diet will provide you with essential vitamins and nutrients your body needs to function properly if your diet is controlled and balanced. But in terms of simple weight loss, the source of the calories does not matter.
There is no doubt that one metabolizes simple sugars differently from protein. But you also metabolize protein differently from complex carbohydrates. And complex carbohydrates differently from essential fats. And essential fats from protein. This is simply a factor of biological digestive processes -- different processes are activated for different food components.
It comes down to personal choice with respect to dietary intake. If you like the Zone, go for it! If you like Atkins, go for it! If WW is your thing, go for it! Because they will ALL work, regardless of the source of the calories IN because they all work through some form of calorie restriction. And 100 calories over your daily maintenance values WILL result in weight gain, whether those calories are in the form of an apple or a 100 calorie pack of Oreos.
The general biological rule (barring disease processes of course) is that if you EAT more than you USE, you WILL GAIN WEIGHT. And if you eat LESS than you USE you will LOSE WEIGHT. The only variable that seems to be at work in this process involves the SPEED and PREDICTABILITY at which you lose weight. Your metabolic rates may vary from year to year, with age, daily activity, season, and so on. But I don't think one has to be overly concerned about the accuracy of BMR and the accuracy of output
in a weight loss phase IF one keeps in mind that, for example, if you weight 244lbs and eat 1400 calories a day plus do 30 minutes of exercise a day, the weight will come off. Perhaps not as fast as you would like, and not in a linear fashion, but it WILL come off.
And sometimes I think we all take this weight loss business too, well, SERIOUSLY. We spend alot of time analyzing what we are eating and doing to DEATH. We obsess about stuff which may be not particularly useful. We can't see the forest for the trees, so to speak. And if you just keep that "forest" in mind -- if you reduce your calories and increase your exercise --, and stop worrying so much about the "trees" -- optimal food combinations, timing, number of meals, grams of protein, temperature of water, BMR, and so on -- things WILL work out just fine and your life will be SO much easier. My motto -- Keep it SIMPLE. Make a few (JUST a FEW) weight loss rules that make sense for you, and relax about the rest. I personally don't have the time to do much else!!!
JMHO

Kira