I often hear many misinformed people make incorrect statements regarding weight loss and weight gain. I’m sure you’ve heard some of the following statements and might even think some have merit: “If you want to build muscle, you need to take a protein supplement,” “I’m going on a special diet right now where I can’t eat past 6pm otherwise I’ll get fat,” “If you eat ‘healthy’, you won’t get fat,” “I just can’t put on any weight,” “I just can’t lose any weight.” These types of erroneous statements consist of a lack of understanding of science – people either don’t know how their bodies process food or they think their bodies aren’t subject to the laws of nature.
Let me break it down for you: unless your energy balance equation is tilted the right way, your goals to gain or lose weight will be utterly futile. Simply put, if you consume more calories than you burn, you will gain weight; conversely, if you consume less calories than you burn, you will lose weight. It doesn’t matter how hard you workout or how much protein you eat, if you don’t consume more calories than you burn, you will not gain weight. Similarly, you can work-out extremely hard and eat “healthy”, but at the end of the day, if you consume more calories than you burn, you will not lose any fat/weight and will gain weight. The energy balance equation governs everyone’s bodies. Your body can’t defy mother nature.
In this article, I will provide you with some background knowledge on what happens to the energy that is consumed from food and explain the concept of energy balance.
Energy Balance Defined
Your body is essentially a machine. Anything your body does requires energy comes from food ingested or from reserved energy stores within the body. The term “energy balance” is a description of the interplay between our energy expenditure (energy out) vs. our energy taken in (energy in). The energy balance equation, just like anything in life is governed by the Laws of Thermodynamics which states that energy is neither created nor destroyed, but transformed. A “positive energy balance” means more energy is taken in than burned so there will be weight gain; in contrast, a “negative energy balance” means that more energy is burned than taken in so there will be weight loss. And of course if your energy balance equation is equal, your weight will remain unchanged.
To get a better understanding of this equation, let’s take a look at each portion of the energy balance equation beginning with energy in. To do this, you need to have a basic understanding of biology. As mentioned previously, your body is a machine that requires energy to perform all of its functions. Food is the source of energy that is used by the body. The substances in food that provide the body energy are called macronutrients and they consist of carbohydrates, proteins and fats.
To use the macronutrients, the body breaks them down into smaller components through a process called digestion. Next, these smaller components are then absorbed in the small intestine and eventually make their way to the blood stream and are eventually further broken down to be used by the body as energy. Now remember the law of thermodynamics: energy is neither created nor destroyed but is transformed. So whatever energy you absorb into the body that doesn’t get used is “transformed” or stored. The excess energy doesn’t just magically disappear – it has to go somewhere and it eventually get converted and stored as fat.
You might be wondering what the body does that requires energy. Your energy out equation is composed of 4 categories: basal metabolism, physical activity, thermic effect of food (TEF), and adaptive thermogensis:
1. Basal Metabolism
This is the metabolic activity that supports the basic processes of life such as breathing, body temperature, the beating of the heart, making new red blood cells, kidney function etc and it is approximately 2/3 of the total energy a person expends a day. Basal Metabolic Rate (BMR) is the rate of energy expenditure by the when performing the body’s metabolic activities. This rate/total is the amount of energy used if you were just laying in bed doing absolutely nothing.
2. Physical Activity
This is the energy expended during the voluntary movement of skeletal muscles and its support systems. The amount of energy needed for any activity depends on your body mass, body weight and the activity that is being done. This component of the of total energy expenditure is the most variable of the 4 categories – basically, the more physical activity you do, the more energy you will burn.
3. Thermic Effect of food (TEF)
Yes, like with all bodily processes, digesting and absorbing food requires energy too. The energy used in TEF is approximately 10% of the total energy intake of food.
4. Adaptive Thermogenesis
This is the energy consumed when the body is adapting to extreme changes in the environment. When the body adapts to a stressor, energy is used to build tissues, produce enzymes and hormones.
The relationship between energy in and energy out
So as you can see, your body is an energy guzzler and requires energy to perform the activities in the energy out portion. As I mentioned before, your body gets this energy from the stored chemical energy in foods. Once the macronutrients are broken down and absorbed, your body will take these substances and use them for energy. I mentioned earlier that excess calories will be stored as fat but let’s look at it in a bit more detail:
Carbohydrates are absorbed into the body as monosaccharides and then end up as glucose. If there’s an excess of glucose, it will get stored first as glycogen in liver and muscle stores. Once the glycogen stores are full, the glucose will be stored as fat.
Fats are absorbed into the body as fatty acids and glycerol. Any fatty acids/glycerol that is not used will be stored as fat.
Proteins are absorbed into the body as amino acids. If there is a positive energy balance and an excess of amino acids, first the body will use what is needed to replace daily losses, then it increases protein oxidation. Left over amino acid after this is stored as fat. If there is a negative energy balance, amino acids will be converted to be used as fuel.
The macronutrients all end up with the same fate if there is excess that the body does not use: they all get stored as fat. It’s basic physiology and our body’s way to store energy to be used for the future. It’s our body’s way of ensuring survival when resources are scarce. It doesn’t matter how “healthy” or “clean” you eat if your calories in is greater than your calories out. The “clean/healthy” foods are still made up of macronutrients and in excess, they will be stored as fat. So you can see how wrong people are when they make statements such as: “carbs make you fat,” “fat makes you fat,” “protein won’t make you fat.” Any absorbed macronutrients in excess will turn into fat.
Now on the other side of the equation, if not enough calories are taken in, the body must/will take and use energy from its reserves. First, the body will use its glycogen and fat stores. After glycogen stores are completely empty, the body will continue to use its fat stores but will also tap into its lean tissue (muscles) to break down protein to use as energy.
Putting it all together
Now do you see why it’s absolutely absurd when people say “they just can’t lose weight” or they “just can’t gain weight?” Part of the problem is a complete lack of understanding of how the body works; in addition, people are extremely terrible at calculating how many calories they are taking in and they aren’t very honest with themselves. How many times do you see that person complain about not being able to lose weight only to find out that in addition to the 3 meals he eats a day, he drinks 2 lattes, eats extra muffins at the office and then drinks copious amounts of alcohol on the weekend? If he’s not burning more calories than he’s taking in, those extra calories don’t just disappear – they turn into fat.
You will also hear young men with fast metabolisms complain about not being able to put on muscle even if they lift weights. They will say that they “eat a ton.” But when you look at their diet, they might only eat 2-3 medium sized meals a day and are definitely not eating enough calories to support daily requirements much less have excess energy to build muscle.
Other complaints you hear are “I have a really slow metabolism so dieting doesn’t work,” or “I have a really high metabolism so I can’t gain weight!” Let’s assume the first person does have a slower metabolism. This just means that the basal metabolic rate for this person will be slower for whatever reason compared to a person of similar age/weight. At most, this person’s BMR will be a few hundred calories lower (compared to a person of similar physical attributes), which means he can’t afford to eat as much if he doesn’t want to put on weight or wants to lose weight. To use an extreme example, how many fat/obese people do you see in a concentration camp? This isn’t to make light of concentration camps but it’s to illustrate the point that you WILL lose weight if you take in less calories than you burn. Similarly, the person with the “fast” metabolism just means that he a higher BMR which means for him to put on weight, he’ll have to eat more.
Changes in body weight due to imbalances of the energy balance equation do not happen over-night. It takes a consistent state of positive energy balance to gain weight and a consistent state of negative energy balance to lose weight. Also, although the energy balance equation must be satisfied when it comes to weight gain/loss, there are some added complexities. For example, not all weight loss is equal. With exercise and diet manipulation, you can influence your body to spare relatively more lean muscle mass and take its needed energy more from its fat stores. We will talk about these details in future articles but these complexities still must adhere to the laws of thermal dynamics and energy balance equation. Just remember: if you eat more energy than you burn, you will gain weight; if you eat less energy than you burn, you will lose weight; and if you take in the same as you burn, your weight will stay the same.