You've heard of macronutrients - protein, carbohydrate and fat. These are the building blocks of our daily diet, yet few people really understand that you need to know what quantities of each to include in order to achieve your goals. Hopefully this post will shed some light on the subject.
Fat is a major source of energy in the diet. Dietary fat contains nine calories per gram, which is more than twice the number provided by carbohydrates or protein. Due to its high caloric content, the chance of becoming obese increases with a high intake of fat.
Some fat is essential to proper body function. Fat fills adipose tissue that helps to insulate the body. Fat helps the body absorb certain vitamins. Healthy skin and hair are also maintained by fat. (source: About.health.com)
Carbohydrates are typically your body's primary source for energy. Carbohydrates are comprised of sugars, starches, and cellulose. Your body must break down carbs in order to turn them into glucose (commonly referred to as blood sugar). Each gram of carbohydrate contains 4 calories.
There are two different types of carbohydrates. Discerning among the two is important, because their impact on your body differ significantly. Simple carbohydrates (sugar) like table sugar, honey , candy, and the like, are digested quickly and give your body an energy surge. These are the ones you typically should avoid.
Then there are complex carbohydrates. Complex carbohydrates are comprised of starchy and fiber-rich foods. They are processed by your digestive system much more slowly than simple carbs are. Examples of complex carbohydrate foods are legumes, fruits, grains, and other vegetables; starchy foods include potatoes, wheat, rice, and corn. (source: About.health.com)
Proteins are necessary for building the structural components of the human body, such as muscles and organs. You also need proteins to keep your immune system healthy, synthesize neurotransmitters, create and signal hormones, and much more. A balanced diet supplies you will all of the protein you need. Meats, fish, seafood, poultry, eggs, and dairy products are significant sources of protein, but you can also get protein from a variety of grains, legumes, nuts, and seeds. Each gram of protein has 4 calories. (source: nutrition.about.com)
How do you know what ratio you're eating?
Let me try to break this down in a simple way that makes sense. Each food that you eat will have some combination of fats, carbohydrates and proteins. For example, a 4 oz baked, skinless chicken breast has 184 calories, 4 grams of fat, 0 grams of carbohydrates, and 35 grams of protein. An avocado has 322 calories, 30 grams of fat, 17 grams of carbohydrates and 4 grams of protein. As I stated above, each gram of fat contains 9 calories, while each gram of protein and carbohydrate has 4 calories. So if you ate a chicken breast and an avocado, you would have ingested 506 calories. The total calories from fat are 9 times 34 = 306, the total calories from carbohydrates are 17 times 4 = 68 calories, and the total calories from protein are 4 times 39 = 156. So of the total calories, 60% come from fat (take the fat calories of 306 and divide by the total calories of 506), 13% come from carbohydrate and 31% come from protein. That would be a ratio of 60/13/31.
So to understand what ratio of your entire diet is made up of fat, carbohydrate and protein, you'd need to track everything you ate and figure out what percentage of calories are coming from each macronutrient. Wow, that sounds hard. Well, it isn't fun, but there are tools like MyFitnessPal that make it a lot easier. All you have to do is log the food and quantities you've eaten, and it knows the macronutrients and calories in each food and will produce a ratio for you.
What ratio should I be eating?
That's the best question yet. The answer is: it depends on your fitness goals. There are many different philosophies on the right combination to produce the right results. The ones I present below are what are typically regarded as accepted ratios. These are the guidelines I used when I lost 75 pounds during the past year.
You'll also need to consider the total number of calories you're taking in as well. I have a blog post about that here. You'll need to consider your BMR and level of activity.
Remember that these ratios assume that you're working out on a regular basis. You can't just modify your ratios to 60% carbohydrate and all of a sudden expect to see your muscles get larger. The higher carbs in this case are to fuel your workouts so that you can perform your workouts better to strengthen your muscles.
What do I do?
So what do I do with all of this information? At the moment, my overall goal is to maintain my current body weight which is about 215 pounds. Given that my BMR is about 2200 calories per day and through exercise I expend another 600 calories per day, my target caloric intake is 2800 calories. Wow, that sounds like a lot! Am I fat? No, I measure about 12% body fat, which is considered athletic. And I have a 34" waist, which is considered healthy for a man. I happen to have a lot of lean muscle. So you don't need to starve yourself to maintain weight loss.
Using the "Maintenance" ratios of 30/40/30 of fat/carbohydrate/protein, that means I should be eating about 0.30 times 2800 = 840 calories from fat, divided by 9 to give 93 grams. And 0.40 times 2800 = 1120 calories from carbohydrates, divided by 4 to give 280 grams. And 0.30 times 2800 = 840 calories from protein, or 210 grams.
So how do I know what foods to eat, what their macronutrient content is and how many calories they contain? Well, all of that is called meal planning. And like I said, free tools like MyFitnessPal make the process a lot easier. You can either use it to track what you've eaten, or to plan what you'd like to eat (then track to ensure that you came close). I have to admit that for the first few months I consulted a personal trainer who prescribed food plans with all of this in mind, and that helped immensely since I was so busy just trying to learn good healthy habits. But over time I learned what foods I liked and generally what a good, healthy day looked like that came within my goal parameters. To this day I still use MyFitnessPal from time to time to help ensure that I'm not way off track.
The bottom line
The bottom line is that you need to eat cleanly and exercise regularly. If you have a specific fitness goal in mind, it helps to know what ratio of macronutrients you should include in your diet in order to achieve it.