I’ll admit it. I continuously fall into this mindset trap: calories in equals calories out. Based on my weight goal, I meticulously count my calories and reward myself with extra calories that I get to consume if I run a few miles that day.
Calories Burned by Metabolizing Food
Yes, we actually burn calories by processing the very food that we eat. But, digesting food typically only accounts for about 5% to 10% of the total calories (energy) that we burn. But what we put in our mouths matters. Our bodies need balanced levels of healthy fats, carbohydrates, and proteins to exist. A single gram (g) of each of these macro-nutrients equals the following number of calories
- 1g Fat: 9 calories
- 1g Carbohydrates: 4 calories
- 1g Proteins: 4 calories
You may think that you can either eat 1 gram of fat or a little over 2 grams of a carbohydrate or a protein to reach your caloric intake goal that day; but this is not the case. Each of the above macro-nutrients is metabolized differently by the body.
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What We Eat Affects Our Metabolic Rate
The thermic effect of food (TEF) is the increase in metabolic rate after eating a meal. ‘While factors such as such as meal size, meal frequency, meal composition, meal pattern, and body composition influence the thermic effect of food’, we’ll focus on which foods we eat since that lies more easily within our control. What we eat has a direct impact on our metabolic rate. Listed below is the approximation of how many calories we burn to metabolize the following food types:
- 100 Calories Protein = 25 to 30 Calories burned
- 100 Calories Complex Carbohydrate = 10 to 30 Calories burned
- 100 Calories Simple Carbohydrate = 3 to 5 Calories burned
- 100 Calories Fat = 3 to 5 Calories burned 
1 Tbsp Olive Oil
Not All Fats are Bad Fats
While healthy fats, such as nuts, avocados, and fish, are very dense in calories and require very little energy to metabolize, you would not need to consume as much since healthy fats typically leave you feeling full quickly. Certain fats are also essential for absorbing fat soluble vitamins, like A, D, E, and K. Ideally, 20% to 35% of your caloric intake should be derived from healthy fats.
1/4 Cup of Peanuts
Protein in Moderation is Great Too
Your initial thought may be, “why don’t I just consume only foods high in protein since I would burn the greatest number of calories that way?” While protein is very important (please note that not all protein comes from animal sources) and is needed for hormones, growth, and metabolic functions, consuming more protein than your body needs will also result in the excess protein being stored as fat. Additionally, long-term excess protein consumption can be a bit exhausting for your liver and kidneys to process. Depending on your lifestyle, protein intake requirements range from 10% to 35% (e.g. if you are a bodybuilder, you would likely lean more toward the 35% intake). 
The Skinny on Carbohydrates
I focus on discussing carbohydrates more than the other macro-nutrients because carbohydrates make up the largest percentage (45% to 65%) of our macro-nutrient intake (it’s what we need the most of) and I really feel that this is the macro-nutrient that the majority of us struggle with balancing in our diets.
As you probably already know, a 100-calorie apple does not equal a 100-calorie cookie. Why not? After all, both the apple and the cookie would be categorized as a carbohydrate and a carbohydrate is a sugar. Here’s the scoop:
Carbohydrates are either simple or complex. Simple means that the body breaks down, or burns through, the simple sugar very easily and quickly. Complex means that the body must work harder to break down the complex sugars into simple sugars before it can be used. 
100 Calories of Peanut Butter Cookie Goodness
The Cookie is Simple
You may notice that if you eat the cookie, you feel a little sugar rush. The simple sugars of the cookie are quickly and easily converted into glucose, signaling your pancreas to release a bunch of insulin to lower the sudden glucose surge. After your body uses the glucose it immediately needs, a small amount of the glucose is converted to glycogen and stored in your muscles and liver. Whatever glucose is left over is stored as fat. Since the simple sugars were metabolized so quickly, you’re soon left hungry again and craving the next sugar rush to get you through the sugar crash. This becomes a very addictive cycle. The cookie only took about 3 to 5 calories to be metabolized.
A 100-Calorie Granny Smith Apple
The Apple is Complex
The apple is considered a complex carbohydrate. The body has to work harder (burn more calories) to break down the complex sugar molecule chains into simple sugars before it is use. If you eat an apple instead of the cookie, you would feel fuller longer and the simple sugars would slowly enter your bloodstream as the complex chains were broken down over time. This ‘slow burn’ boosts your metabolism and gives your body time to respond to small amounts of glucose it is receiving; as a side note, this also makes your pancreas happier. You would not experience the sugar rushes followed by the sugar crashes. The apple took roughly 20 calories to metabolize. 
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Burn 60 Calories Instead of 15 Calories Simply By Choosing the Right Food
Though the calories burned in the above examples during digestion are small, they definitely add up. Imagine if you ate three complex carbohydrates per day (like a carrot, an apple, and maybe a whole grain slice of bread) instead of three simple carbohydrates (like a small bag of chips, a big cookie, and a soda) for your snacks. You would burn an extra 60 calories per day instead of 12 to 15 calories. Now, replace simple carbohydrate items in your main meals with complex carbohydrates and image how many additional calories you would burn by simply digesting your food.
Eliminating or even limiting processed simple carbohydrate foods to 5% to 10% of our caloric intake will boost our metabolisms and help us meet our weight and health goals. While the internet is a great source for clarifying which carbs are simple and which carbs are complex, the most sure-fire way to determine this is to avoid eating packaged foods…especially ones that have more than just a few ingredients listed on the package. Hopefully we can plan and choose our simple carb cheat foods more wisely now so we can still meet our goals.
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