An article that was published by Dr. Doug Anderson in Dynamic Chiropractic pointed out an interesting study that was done on a group of people over a 3 month period. The researchers wanted to see if there was a difference in people gaining weight when they consumed the same amount of extra calories, but with one group eating more fat, another eating more protein, and another eating more carbohydrates.
The results were interesting, from the article:
"To gain body fat, the type of calorie makes LITTLE DIFFERENCE when a person eats more than what they need.
To gain body weight, which includes muscle and fat, extra protein will add muscle EVEN WITHOUT EXERCISE.
The average amount of protein consumed (grams) DOES NOT MAKE MUCH DIFFERENCE once the requirements are met."
Dr. Anderson states these results support strategies that recommend higher percentages of dietary protein when total calories are insufficient because we diet to lose fat, not muscle.
So we see from the study that when we eat too much, it doesn't matter if its more carbs/protein/fat. Too many calories is always bad. This is why almost any dietary change that involves lower calories will usually be somewhat successful.
Doug Anderson, DC, Fat Gain, Weight Gain, and Calorie Source. Dynamic Chiropractic, 2013, January 15; 8