Are all calories created equal? What's your take on it?

Body mass is a function of energy balance - an energy deficit is both necessary and sufficient to lose weight.
In that limited sense, "a calorie is a calorie," as much as I dislike that phrase.
If you burn 2400 calories per day, you will have a net loss of body mass by consuming 2000 calories per day of pure sugar, or 2000 calories of chicken breast, broccoli, and walnuts.

The macronutrient and micronutrient profile of your diet affects body composition and health. Without sufficient protein, for example, the body mass that is lost may include more muscle or other lean mass than necessary, and less adipose. Deficiencies in vitamins and minerals can adversely affect body composition as well, in addition to myriad other health problems and risk factors. Food choices also have indirect effects on weight loss and dietary adherence through hunger/satiety, mood, and energy levels/training performance.

So in the end, while weight can be lost on any kind of diet as long as there is a calorie deficit, nobody sane argues that the composition of the diet is irrelevant for all purposes. It matters a great deal for body composition and overall health.

another relevant read, a study published in the AMA Journal, proving Basically says that "healthy carb" (low-glycemic-index) is superior to low-fat or low-carb: http://online.wsj.com/article/SB10001424052702304458604577490943279845790.html

Just like the story of the three pigs who built their houses out of straw and sticks and bricks, what we choose to "build" our bodies with will determine how well they stand up in the end.

Quality trumps Quantity! 100% agree on this. My car analogy: Natural Fat= 91 octane fuel (Optimal power, max mpg), Carbs= Race Fuel(max power, low mpg), Protein= The shop (to keep all the systems up to par). They all have their purpose. I found the ratio my body likes. It's up to all of us to figure that out too in order to efficiently attain the results we want! Work smarter, not harder.

I just read another article addressing this issue.

http://blisstree.com/eat/nutrition/high-protein-diets-are-all-calories-created-equal-258/

My diet is 90% protein and fat. Fat is villainized and so misunderstood. Eat fat from natural sources and avoid fat from processed sources. TRANS-FAT is the processed junk you want to steer away from.

CJ, I would agree that Fat is/has been targeted as 'bad'. Fat in moderation can be a positive. I'd also suggest that high protein diets (for adults) are physiologically stressful and likely lead to net negative effects in the long term. For instance, high protein diets clearly, and quite significantly shorten lifespans in animals. Of course, as a disclaimer, I admit to be a hi-carb (complex, naturally sourced, with fibers) proponent!

Most people equate Atkins, or other low carb diets with high protein. In reality, when Atkins is followed according to plan it is high fat, moderate protein, and low carb. I agree CJT, real food, that is not highly processed will always be the healthiest option.