More than Calories: Macro Basics
In the quest to lose weight have you ever been told “Just cut your Calories.”? Pretty simple, right? Eat less, exercise more… and the pounds should melt away. So, why is it that it is so much easier to gain fat than it is to lose it? Well, it’s because there are more factors than just Calories consumed vs. Calories burned that determine our body composition.
First off, what is a Calorie? The definition of a Calorie is the energy needed to raise the temperature of 1 kilogram of water through 1 °C, equal to one thousand small calories. The Calories we eat in food are actually kilocalories (1,000 calories). In other countries you will see them labeled as a kcal… but, in the U.S. we simply capitalize the “C” and refer to it as a Calorie. So, since a Calorie is simply a measurement of energy, why isn’t it a simple math equation?
First off, not all Calories are created equal. There are some doctors, and even Dietitians, that will argue that a Calorie is a Calorie is a Calorie… but, this simply isn’t true. Where your Calories come from matters, because different molecules are used for different processes in our bodies… this is where we get into macronutrients or “macros” for short. You may have heard this term, as it is widely used in the diet and fitness community these days… a macro is simply a breakdown of our where a Calorie comes from. The 4 main categories are: Carbohydrates, Fat, Protein, and Alcohol. These four Calorie sources act very different in our bodies.
A carbohydrate, or “carb”, is used as energy in our bodies. There are 4 Calories per gram of carbohydrates. For most people this is their primary fuel source. There are complex carbs, which include higher levels of fiber (a starch structure that our bodies cannot break down) which are slower to break down in our GI tracts… and there are simple carbs, which have little to no fiber, and are broken down very quickly in our GI tract. Carbs are not inherently bad or good, but all carbs (except fiber) is broken down to sugar to be used at the cellular level. This is when it is used as a fuel source. Carbs cause insulin (a hormone) to elevate. Insulin then moves sugar into the cells to be used immediately, whatever cannot be used immediately will be stored. A small amount can be stored in our liver and our skeletal muscles as glycogen to be tapped into for quick use, but anything beyond that small amount will be sent to our fat cells to be stored for times of famine… the issue with this is… none of us experience famine these days. 😉 When blood sugar levels fall, our bodies will signal to us that we need to eat again way before we start tapping into fat stores… to begin using stored fat as fuel, you will need to go a prolonged time without food to switch over to fat burning mode…
Fat is also a fuel source. There are 9 Calories per gram of fat. So, it is much more Calorie dense than a carb… but, that’s not necessarily a bad thing. Fat is broken down into fatty acids to be used at the cellular level. We can use either sugar from carbs or these fatty acids (ketones) to fuel our bodies and brains. We all have the capability of using either/or fuel sources (this is how we were designed to withstand famine), but I believe the low fat craze of the 80s and 90s has contributed to a lot of us being inefficient at using fat for fuel. We’ve become so dependent on carbs, that our bodies signal to us to replenish blood sugar long before we switch to ketones. However, if you are someone who uses fat as your primary fuel source you most likely will not experience hunger as frequently. This is because fat does not stimulate insulin production, causing a rapid drop in blood sugar. Don’t fear fat… dietary fat has to go through the metabolic process of being broken down just like other macronutrients… it doesn’t directly end up on your hips. 😉 Dietary fat is used in our bodies to produce hormones, and is necessary to absorb vitamins A, D, E, and K. Eating an extremely low fat diet will cause hormonal imbalances, and can lead to nutritional deficiencies. When it comes to dietary fat, the source of fat is important. Trans fats and high levels of omega-6 fats are very inflammatory to our bodies… which is a whole other topic… but, fat is necessary to be healthy. When it comes changes in body fat levels, you just need to consider the overall amount of Calories you are consuming in a day… if you consume too many overall Calories (from any source) it will be stored as body fat.
Protein is used for building in our bodies. There are 4 Calories per gram of protein. Protein is broken down into amino acids to be used at the cellular level. They are then used to repair tissues, and for other processes. Some of these amino acids are actually produced by our bodies (nonessential amino acids) while others must come from our diet (essential amino acids). Protein is not a great fuel source for our bodies, but it can be converted to one if necessary. The process is more difficult for our bodies than breaking down carbs or fat for energy… it will break them down first to meet energy needs, then move to protein. This is why muscle breakdown occurs during severe, prolonged Calorie restriction… the body will breakdown muscle and organ tissues to produce those nonessential amino acids that are necessary for life. Exercise and stressors, such as surgery, increase our protein needs, because it will be used in the repair process. Protein is also necessary for our detox pathways in our liver to function properly. So, it seems that protein should make up the bulk of our macros then, right? Nope. Protein will be converted to glucose if too much is consumed, and can be stored as body fat, if Calorie levels are too high… so, don’t think protein is the “freebie” macro. Also, extremely high protein consumption is now being linked to possibly increasing risk of diseases such as cancer risk over time, as it stimulates rapidly dividing cell pathways. Just enough, and no more… is the way to go with protein.
Alcohol is it’s own category. There are 7 Calories per gram of alcohol. It is not really used as a fuel source, but it does take priority in our bodies when consumed. The liver (our main detox organ) sees it as a poison, so it prioritizes it’s breakdown and removal from the body. The body will more than likely breakdown the other macros to be stored as body fat, while it focuses on bringing down blood alcohol levels… this is where that “beer belly” comes from. 😉 If you consume alcohol, do so in moderation.
So, as you can see… a Calorie is not just a Calorie. Yes, in a controlled laboratory a Calorie will measure the same no matter the source, but our bodies are a different type of laboratory… everything we eat sends a signal to our bodies via hormones to use that substance in a different way. The amount of each macro necessary for optimal health and weight is different with everybody. Things such as activity levels, muscle mass, and even the microbiome (gut bacteria) can affect how much of each macro a person needs.
The moral of this story is… if your overall Calorie intake is not greatly exceeding your energy expenditure, but you are not able to lose body fat… you may need to look at macronutrients as the next step. There are other factors to consider, but understanding the basics of how each macro is used in your body is the first step to determining where you are overconsuming or underconsuming when it comes to energy balance and body functions. You can then begin to identify what may be contributing to that stubborn extra body fat. Knowledge is power. 😉
In good health,