Although not based on popular diets (the high-protein diet, for instance, does not provide the same distribution of nutrients as Atkins), the four eating plans had their particular distinctions (i.e: one offered 35 percent of calories from protein, while another increased the amount to 65 percent of calories from protein).
The conclusion? "All produced weight loss and improvements in lipids [as well as] reduction in insulin. The key really is that it's calories, not the content of fat or carbohydrates -- just calories," summarizes study co-author Dr. Frank Sacks of the Harvard School of Public Health.
Or, as the study itself beautifully encapsulates it: "reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize."
No matter which of the four diets the 811 overweight participants were on, they all "had a[n average] 750-calorie reduction per day."
Not surprisingly, they all lost weight.
Note that even the higher-in-fat diets followed American Heart Association guidelines (mainly sufficient fiber intakes and limited saturated and trans fat intake).
Let this be even further proof to the "saturated fat is the healthiest fat; everyone is lying to you!" camp that diets rich in polyunsaturated and monounsaturated fat do indeed lead to improved lipid profiles and weight loss.
Adding to the uniqueness of this study is that it is one of the few that tracked participants on these diets for two entire years.
How will "calories don't matter, it's all about limiting carbohydrates"enthusiasts explain yet another study showing weight loss can be accomplished while eating a substantial amount of carbohydrates?