Originally Posted by
RomansFiveEight
Like Dos says, it's sort of a myth that a calorie is a calorie (or if you wanna be really pedantic, a kilocalorie or kCal. What we're calling a "calorie" is actually a kCal, which is 1,000 calories.). Calories in and out does matter and the calculations are actually pretty ballpark for most people; but you still need to be eating a healthy, balanced diet. Calories come in Carbs, Protein and Fats. A diet low in calories but that is primarily carbs and fats is going to be less successful than a balanced diet that balances appropriate amounts of all three.
Er, up to a point. I'm certainly not arguing against a balanced diet, but there does seem to be a wide variation in how people respond to similar diets. Some do very well on low carb, some seem fine on several hundreds of grams of carbs a day. In my own case, the calories in/calories out thing seems to work pretty well whatever the source of the calories.