Now that you know calories come from protein, fat and carbohydrates, and how many calories each of these macronutrients provides, you will want to know how much each macronutrient should contribute to your diet. The answer is commonly expressed in percentages and referred to as micronutrient ratios, or simply nutrient ratios.
In order to obtain optimal health, and the slim body that comes with it, you need to eat healthy foods. But it's not enough to simply eat healthy foods; the foods must provide a healthy balance of all three macronutrients.
There is no one set of numbers that is best for everyone, and the percentages that are best for you can change with your circumstances. At different times your goal might be to lose body fat, gain muscle, or both.
The USDA Food Guide recommendations, based on a diet of 2000 calories per day, include 91 grams of protein, 65 grams of fat, and 271 grams of carbohydrates. This equates to 18% of calories from protein, 29% from fat, and 53% from carbohydrates.
While one of the goals of the Food Guide is to reduce consumption of fat, many would consider 29% too high for optimal health. But perhaps it's a good compromise for the average American who might not be willing to reduce fat consumption further.
In his book Burn the Fat, Feed the Muscle, author Tom Venuto recommends a baseline diet of 30% protein, 15-20% fat, and 50-55% carbohydrates. These percentages are referred to as "baseline" because they are only meant to be a starting point.
The book instructs you in how to modify the baseline percentages based on your body type and goals. And how, after measuring your initial results, to further refine them to meet the requirements of your particular body.
The percentage for protein is higher than the USDA recommendation because Burn the Fat, Feed the Muscle is based on the concept of eating properly and exercising to ensure that you do not lose muscle while losing fat. Losing muscle causes your metabolism to slow and weight loss to stop.
You will find that most diet plans recommend specific proportions of the three macronutrients. Keep in mind that any diet plan proposing extremely low proportions of any of the three macronutrients may be designed for quick weight loss and have little chance of long-term success. People often find that they tire of eating in such extremes and quit, rendering their diet a failure.
Once you have determined the macronutrient ratios you will be using, it's easy to calculate how many grams of each macronutrient you should be eating. But first you have to calculate the total number of calories you will eat in a day as described in Calculating Daily Calorie Needs.
For example, if your daily calorie needs are 2000 calories and you choose proportions of 30% protein, 20% fat and 50% carbohydrates:
This tells you how many grams of each macronutrient you should be eating to achieve the ratios you have chosen. Another way of looking at it is to calculate the ratios of what you are eating, and then make adjustments accordingly.
Butter and oils contain only fat, and sugar and honey contain only carbohydrates. But foods comprised of a single macronutrient like these are the exception. Most foods consist of a combination of two or all three of the macronutrients.
To see the proportions of a food you eat, simply calculate the food with the Food Calculator. If a food doesn't appear in any of the food lists, you can enter the grams of protein, fat and carbohydrates with the Add Foods feature and then calculate it.
To see the proportions of a combination of different foods, calculate each of the foods and let the results accumulate. The results will indicate the percentage of protein, fat and carbohydrates for the total of the foods you calculate.
The formula used by the calculator is quite simple, and you can do the math by hand if you prefer: