How does it work?!

"http://www.nutritionandmetabolism.com/content/1/1/15"

Indeed, thermodynamics,ie. as measured by calories, describes all diet
plans. Excessive calorie intake is stored as fat. Reducing calorie
intake below daily energy requirements will in time cause fat stores to
be used to replace the difference. Some differences in the calorie cost
of various metabolic pathways required in digesting various nutrients
can affect the energy process as described above. High protein intake
is said to require more energy to metabolis by a small amount then carb
and fat,ie. it takes more caloric energy to turn proteins into forms
usable as energy sources for cells. Once all the calorie arthmetic has
been done balancing the various combinations then we arrive at the most
basic statement of weight loss - all diets in the end cause weight loss
or gain because of the number of calories consumed.