What’s the best macronutrient breakdown for fat loss? 40/40/20 or 50/30/20?
First and foremost, this is obviously very goal dependent. Meaning, that these numbers would most likely be different whether one’s goal is primarily fat loss or muscle gain. That aside, the idea of looking at macronutrients as a percentage of your total caloric intake is highly overrated. There is no magic or even any great advantage to any specific percentage of protein, carbs, or fat in your diet.
By using percentages you’re working on a ‘relative’ scale (relative to your total calories) and there are potential disadvantages to using this approach. For example, 40% of 1500 calories is a lot different than 40% of 2500 calories. This approach fails to take into consideration overall caloric intake, which is affected by a number of different variables – the amount of muscle you carry and whether your dieting for fat loss or more focused on muscle gain for example. So while the percentage is constant, the absolute number of protein, carb, or fat grams is much different, and this is what is important – how much you’re putting in your mouth. Even with what seems like good percentages, you could still be getting too little or too much of any macronutrient. Maybe you’re shooting for 40% protein; assuming 1500 calories, this works out to about 150 grams of protein. Depending on one’s bodyweight, this could be reasonable. However, let’s take that 40% and apply it to a 2500 calorie diet. That same 40% now equates to 250 grams of protein. Something tells me this is likely overkill for most of women – regardless of what someone might tell you. The science does not support the idea of huge protein intakes. In the end, the wisest approach is to focus on how much of each macronutrient you’re eating per pound of bodyweight. You could be eating 40/40/20 every day, but if you’re eating 10000 calories a day, it doesn’t matter.
What matters is how much you’re eating, not the relative amount of one macronutrient to another. The most important aspect of any nutritional program is the overall calories; how much you’re eating for your body. The most important elements are setting the right caloric intake, and getting adequate protein and essential fatty acids. Everything beyond that is secondary.