When it comes to losing weight, reducing your daily calorie intake is widely recognized as necessary. Does it matter where you get your calories, though?
Plenty of debate surrounds the question of what percentage of dieters’ daily calorie intake should come from each macronutrient. Macronutrients—fat, protein and carbohydrates—are the three sources of calories in food.
A two-year-long study published earlier this year in the New England Journal of Medicine compared different diets to find out if it mattered where calories come from. The study participants ate similar diets and took up similar exercise routines, but were assigned to diets with different macronutrient ratios.
Comparing Different Diets
The study compared several different types of diets: two high-fat, two low-fat, two average-protein and two high-protein. The researchers randomly assigned 811 overweight, adult participants to four different diets with varied macronutrient ratios.
- 20% fat, 15% protein, 65% carbohydrate
- 20% fat, 25% protein, 55% carbohydrate
- 40% fat, 15% protein, 45% carbohydrate
- 40% fat, 25% protein, 35% carbohydrate
None of the diets were any more or less effective than any of the others.
After six months, people from each diet group had dropped an average of six kilograms, or about 13 pounds.
A year into the study, the participants had begun to gain back the weight that they’d lost.
At the two-year mark, some of the groups were doing about the same as one another. The groups with 15 and 25 percent protein had similar results, as did those with 20 and 40 percent fat and those with 65 and 35 percent carbohydrates.
At the end of the study, the participants had lost an average of four kilograms, or about nine pounds.
All of the diets were just about equally beneficial for heart health.
Each diet reduced the risk of cardiovascular disease and diabetes.
The low-carb diet increased HDL (good) cholesterol levels the most.
All diets caused triglycerides to drop by 12 to 17%.
Do Macronutrient Levels Matter?
A calorie is a calorie, no matter where it comes from. The study found that regardless of the macronutrient ratio, each group lost about the same amount of weight. The participants had similar levels of hunger, satisfaction, cravings and happiness with their diets regardless of their group assignment.
Reliable, accurate weight-loss information is also important. The participants weren’t just put on a diet and sent home. At the start of the study, they were taught about the nutritional content of their diets. For the two years that they participated, they received reinforcement through group and individual counseling.
What Type of Diet Should I Follow?
The important thing is that you reduce your calorie intake. Weight loss will follow naturally from that. One macronutrient ratio will be just as successful as another, so you can choose whatever you prefer. A diet that suits your own preferences could increase your chances of success because you won’t feel as deprived. Because all of the diets worked about the same, you should feel free to choose whichever macronutrient ratio you’ll be able to maintain.