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The Skinny on Protein, Carbohydrates and Fats

The right combination of carbohydrates, protein and healthy fats is critical to reaching your diet and fitness goals. Learn how it all comes together on your plate.

You’ll often hear myself or fitness and nutrition experts discuss the importance of “balanced-meals” to people who are trying to stay fit and in-shape. But what is a balanced diet? And why is it so critical?

A balanced diet simply means that you provide your body with all of the basic nutrients that it needs to provide you with energy each day, as well as to repair and build tissue.

Even if you laid in bed all day, your body still requires around 1200 calories just to fuel basic functions like breathing, digestion, cellular repair and even thinking. The more active you, the more calories you need.

But calories alone are only part of the picture.

Your body also requires amino acids from protein and lipids from dietary fat to maintain, regenerate or repair tissue, whether that’s skeletal muscle, connective tissue, skin, or nervous tissue.

Protein, carbohydrates and fats are often referred to as “macro-nutrients” because your body needs large amounts of them to perform basic cellular functions.

“Micro-nutrients”, on the other hand, are things like vitamins and minerals, which your body uses in smaller amounts to maintain healthy, functioning cells, tissues and organs.

Let’s take a closer look at each macro-nutrient and the role it plays in remaining healthy and fit.


Carbohydrates are the body’s primary source for fuel.  With the exception of some isolated populations (such as the Inuits, who traditionally subsisted primarily on fats and proteins), carbohydrates comprise the majority of calories in most modern human diets.

Carbohydrates are found in a wide-range of foods including grains, breads, beans, nuts, milk, vegetables, fruits, cookies, sugar and soda.  Because of their molecular structure, the body can break them down quickly and efficiently into glucose, which can be readily used by the body as energy.

Carbohydrates come in a variety of forms including sugars, starches and fiber. Depending on their structure, they may also fall into one of two groups: simple carbohydrates and complex carbohydrates.

  • Simple carbohydrates include sugars like sucrose (table sugar), fructose (fruit sugar) and “grape sugars” which are glucose or dextrose.  Of the three, glucose and dextrose are the simplest forms and the carbohydrates most easily utilized by the body for energy since they are the most easily digested.
  • Complex carbohydrates, on the other hand, contain three or more linked sugars, and thus require the body to work harder to break them down into glucose for energy.  Some complex carbohydrates, like fruit or vegetable fibers, for example, cannot be broken down by the body and are passed through undigested.

In recent years carbohydrates have gotten a bad rap. Part of this stems from the popularity of low-carb, high-fat diets like Atkins which encourage people to reduce carbs to extremely low levels, and part of it comes from emerging research around the health risks associated with the consumption of large amounts of simple, refined carbohydrates.

Carbohydrates themselves are not bad. They play an important role in nutrition, because they are a quick and efficient way to deliver energy to your cells, which can power your workouts and every day activities.

The key here is to preference complex carbs over simple carbs. Complex carbs are lower on the glycemic index, and thus don’t cause the quick spikes in blood sugar that simple, refined carbs do. These blood sugar spikes have been linked to increased risk for diabetes, metabolic syndrome, heart disease and obesity. There is also some evidence that high-glycemic diets may also encourage certain types of cancer.

Good sources of complex carbohydrates include whole grains like oatmeal, brown rice, and whole wheat, as well as fresh vegetables and fruits. 


Next up is protein.

Protein is made up of amino acids, which are the building-blocks of all cells … and life.

Protein is used by the body to build, maintain and replace tissue (including muscle, hair, skin ,organs and glands), as well as to produce hemoglobin, maintain proper immune function, and produce essential hormones and enzymes.  Protein can also be broken down into glucose (although not as efficiently as carbohydrates) for energy. Without protein, your body would be unable to build muscle and carry out many of its essential functions.

Foods that contain protein are broke into two groups: complete proteins and incomplete proteins.

  • Complete proteins contain all nine essential amino acids that the body cannot otherwise produce on its own. With the exception of soy beans, complete proteins are only found in animal foods like meat, poultry, fish, eggs, and milk and dairy products.
  • Incomplete proteins lack one or more of the nine essential amino acids.  Incomplete sources of protein include most vegetables, as well as nuts, beans, seeds, peas and grains. Soybeans, however, are a complete protein.

Although vegetable sources of protein are incomplete, you can combine them to arrive at a complete protein. For example, by combining brown rice and beans, you get all nine essential amino acids. This is why it’s even more critical for vegetarians or vegans to have carefully balanced meals when it comes to incorporating different sources of non-animal protein into their daily diet.

Also, while it is not necessary to consume all nine amino acids at the same time to meet your basic protein needs (the body can actually “pool“ amino acids for later use), there may be benefits to consuming complete proteins at certain times of the day.

For example, having all nine essential amino acids available to the body immediately following an intensive workout may help with recovery and blunt catabolism (muscle breakdown.)

Protein is especially important for individuals who are engaged in intense physical activity or training, because it plays such an important role in the creation and repair of muscle and connective tissue. For those individuals, daily protein requirements may be greater than among the general population.


Like carbohydrates, fats have acquired something of a bad reputation, especially among dieters.

Part of this was fueled by research three decades ago that linked diets high in saturated fat with increased risk of heart disease and certain cancers, and part of it was the public’s tendency to lump all fats together as “bad.”  When food marketers jumped on the bandwagon in the 80s and began introducing “fat-free” foods, it seemed that everyone became obsessed with eating less fat, even if that meant eating more sugar and refined carbs than ever before.

However, fats are an essential macro-nutrient and some dietary fat is required for survival.

Indeed, the body needs fat to carry out a number of important processes. For example, some dietary fat is required to absorb certain fat-soluble vitamins such as vitamins A, D, E, K and caratanoids.  Fat also plays a role in maintaining cell membranes, and people need some body fat to cushion their organs. The body even needs some cholesterol to produce certain key hormones, such as testosterone. Fat also is a concentrated form of energy, and when consumed with carbohydrates can slow their digestion and keep blood sugar levels stabilized.

More importantly, recent research has started to distinguish between the protective qualities of certain healthy fats, like the Omega 3 fatty acids contained in fish and flaxseed and monounsaturated fats from things like olive oil, from the “bad” fats like saturated and Trans fats.  Indeed, some researchers are even questioning whether the original studies linking diets high in saturated fat with increased heart disease are as conclusive as originally thought.

Bottom line is that healthy fats from sources like olive oil, fish, avocados and nuts and seeds have a place in any fit person’s diet. While it’s still a good idea to avoid excessive saturated fats and Trans Fats (which ironically, were once considered “healthy” substitutes for saturated animal fats like lard or butter), going the “no-fat” route is probably a sure-fire ticket to a fatter mid-section. And you miss out on all of the protective benefits of healthy fats in the process.

Putting It All Together: What’s the Right Mix of Carbs, Protein and Fats?

So now that you understand the role of each macro-nutrient, let’s get back to that “balanced-meal” thing.

Balancing your carbohydrates, proteins and fats is really a matter of percentages. There are basic guidelines issued by the USDA around recommended daily intake for carbs, protein and fats, but each individual is different and the USDA recommendations are based on an average person consuming either 1500 or 2000 calories a day.

If you consume more calories because of your training regimen, your percentages may still fall within these guidelines, but your total grams of carbs, protein and fats will be higher than the average person.The USDA recommendations also assumes average activity levels, which may not be appropriate for someone who is very active, is engaging in regular weight training, is an athlete or is training for a marathon or triathalon.

Also, some people find that they are more sensitive to carbs in terms of weight gain, and have better results managing their weight by customizing there macro-nutrient profile to emphasize slightly more protein or even fats in their overall diet.

The USDA recommends that 45%-65% of a person’s daily calories come from carbohydrates, 10%-35% from protein and 20%-35% from fats. While the fat percentages may seem high, it’s important to realize that fat has more calories per gram than carbohydrates or protein.  So while the percentage is high, the actual amount of fat that you consume under these guidelines is fairly low typically less than 60 grams from a 2000 calorie diet.

Protein: How Much Is Enough for Fit People?

In terms of protein, there is debate over how much protein active individuals need each day especially those engaging in weight or resistance training or athletic activities.

The USDA doesn’t make a distinction between athletes and average people with lower activity levels when it comes to protein. The recommended minimum amount for men ages 19-70 is 46 grams of protein a day, and for women in the same age group, 46 grams of protein.

If you are performing intense weight training and are very active, your protein requirements may be significantly higher anywhere from 0.8 grams per kg of bodyweight to 1-1.5 grams per kg of bodyweight.

While the USDA has not issued revised protein guidelines for individuals performing weight training or endurance exercises, there is a fairly convincing body of peer-reviewed research that does suggesthigher protein consumption for people engaged in these types of activities. Those studies tended to look at protein consumption in excess of 1 gram per kg of bodyweight.

Again, its important to remember that the total grams of protein that you consume are a percentage of your overall calories. So if you are eating  1800 calories a day, and 34% percent of them come from protein, youll be consuming around 637 calories from protein, which is 159  grams of protein each day. While the absolute number may seem high, this is still within the US RDA guidelines.  This is why absolute recommendations for how many grams of protein you should eat tend to under-estimate actual protein requirements.

Meal Planning: How Can I Make Sure Im Getting the Right Mix of Carbs, Protein and Fats?

While you can certainly track all of this right down to the percentages and grams in your food log or with a calorie counting program, it’s not always very practical.

A good rule of thumb is to always include a complex carb, a protein and a healthy fat in every meal or snack.

This is actually not terribly hard to do.

For example, if your lunch was a turkey sandwich on whole wheat bread with lettuce and tomato and a half serving of almonds, you’d be at a mix of 37% carbs, 33% protein, and 30% fats. This is actually very close to Dr. Barry Sears Zone Diet ratio of 40:30:30, which in my personal experience is a good target to aim for, especially for someone who is trying to gain muscle and shed some fat.

Bottom line is that specific ratios can vary slightly, provided you are making good, solid choices about the kinds of carbohydrates and fats you are including along with your protein.

The main objective should be to always have each of the three macro-nutrients in each of your 5-6 small meals each day. This will ensure that you always have the critical nutrients available to your body, will stabilize blood sugar and prevent hunger pangs later in the day, and will discourage you from overeating and storing the excess calories as fat.


Comments (8)

  1. Kenshaila Davis (1 comments) says:

    I want to lose weight

  2. Burn Calories Fast (4 comments) says:

    While I think protein is obviously very good for dieters I think people really overdo it. The body can only process so much protein regardless of how much working out you do, so all of these super protein shakes just go to waste.

    The same goes for the low fat and low carb crowd, if cutting out something worked perfectly we would all just do it, but our bodies need it, you just need to find the right balance.

    Great article, people tend to make dieting out to be something difficult when it really isnt. Dont overdo anything, work out when you can and you will lose weight!

  3. Laura Pinette (1 comments) says:

    Looking for information about combining incomplete proteins like rice and beans, and what is the carb content when combining. Does that change to double the carb content as well, or does the chemical content change when it changes to complete protein? What is the serving size for rice and beans or other combos?

  4. Matt (183 comments) says:

    Hi Laura, thanks for stopping by and participating.

    Im trying to figure out what your concerns are around carbs. Are you on a low-carb diet right now?

    Remember, all carbs are not bad. The complex, fiberous kind, which come from whole grains, beans, vegetables and whole fruits like apples, produce a very different response in the body than simple carbs like table sugar (sucrose), white rice, or white bread.

    The problem with simple carbs is that they cause spikes in blood sugar, which can faciliate fat storage and blunt fat burning.  They also can cause you to feel tired later, once the original “sugar high” wears off.

    However, when you combine high fiber carbs together, you slow digestion and help keep blood sugar levels more stable.  So carbs arent necessarily the enemy, but rather the types of carbs you eat.

    In terms of beans and rice, combining the two will create a complete amino acid profile (a complete protein.)  Beans are excellent foods, because of their high fiber content, as well as the phytochemicals present (which may have antioxidant properties.) They are also very filling and satisfying.

    When you choose rice, go for the brown version, versus white, which keeps more of the nutrients and fiber intact.

    Carb content is an issue of serving size. Yes, the carb content will double if you combine a serving of beans and a serving of rice together, but remember that the fiber lowers the glycemic load of these sources of carbohydrates.

    A serving of rice is typically a half-cup cooked (1/4 cup uncooked) and a serving of beans is a half-cup.  Combined this would be about 52 grams of carbs and about 300 calories with 7 grams of fiber.

    So, if you wanted to combine them without having two servings of “starches” together, you would combine a 1/4 of beans and a 1/4 of cooked rice. Make sense?

    Chemical content does not change when you combine the foods because of the proteins. Its still a carb, its just now a complete protein.

    Also, understand that there are other sources of whole grains that you can try in place of rice and alongside beans. Quinoa is a great whole grain, that actually has a complete protein profile on its own.  Pearled barley is also a great grain that can serve as a rice substitute, and its very high in fiber as well much higher than brown rice.

    Try these grains and see what you think.

    Did this answer your question?

    Best of luck!

  5. AMY (4 comments) says:

    I am a vegetarian and love to eat healthy. I am getting back into my workout routine and need to get my nutrition balanced. Ideas of foods to eat before and after workouts and meal ideas. Thanks!

  6. Saskia Grunberger (1 comments) says:

    Another complete protein that you did not mention is the grain quinoa; not only is it good for vegitarians, but also for anyone seeking more variety in their diet.

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