I'm starting with a link :

The Sensible Middle Part 1 In Defence of Calories

If you've ever dieted, make yourself a favor and read it. It's not ground-breaking but it puts things into perspective. The author brings up everything wrong about the calorie demonizing movement :

Quality is more important than quantity
Calorie theorists imply you are sloths not expanding enough calories
Fat people eat just as much as skinny people
Calories make you obsessive
Counting calories doesn't work
Hormones are the real culprit and solution

Thermodynamics can't be beaten. A recent article in Science even explains it's being re-explored as a theory of everything to finally reconcile quantum physics and Einstein's relativity. I you want to lose weight, eat less. Fast for five days and you will lose weight. Guaranteed. But here's the catch. What weight will you lose ?

Here is my recent weight change :

And this graph is completely irrelevant. You don't want to lose weight. If aesthetics is your goals, and it is, you want to lose fat. Enter two relevant graphs :

You want to gain muscle and lose fat. Now you might wonder why the weight gain doesn't add up to the muscle gain and fat loss (6-1.6 = 4.4 which is not 3). I think it's because of water weight. The program I'm using here is called trendweight.com and it actually makes my fitbit measuring fluctuations comprehensible.

But back to what you lose, it's obvious you'll always need a calorie deficit. Only to determine the nature of your losses, just as to determine the nature of your gains, you'll need to get your macro-nutrients right. More precisely your protein intake. Whether you then opt for carbs or fat to complement is your choice. Personally I go for fat. Is it more effective for fat loss ? I haven't run a test using carbs but compared to when I used to eat carbs, energy levels are more stable throughout the day.

So that's a primer on diet design. Calories first. Macros second. But there's a lot more to take into consideration. Stay tuned !