Energy Balance Part 1
February 20, 2020 | Evolistic Health
The only thing that dictates whether we gain weight or lose weight over a long period of time is energy balance. We say “long period of time”, because there are many factors that can change your weight acutely, such as water weight and fibre intake. As energy balance is the only thing to dictate weight change, it is, therefore, the most important factor to focus on. Yes, that is right, focus on this before you focus on meal timing and supplements. When we say energy balance, we mean the balance between how many calories you take in (we will refer to this as energy intake) and how many calories you expend (we will refer to this as energy expenditure). There are many factors that contribute to both energy intake and expenditure, and we hope these are made clear in the graphic below.
RMR (Resting Metabolic Rate) - Simply put, this is how much energy our bodies use to stay alive, when in a completely rested state. To accurately measure someone's RMR, they would need to be lying down, awake and fasted for a long period of time (-3-6 hours). This energy goes toward basic bodily functions, such as breathing, brain function and the production of proteins.
Someone's RMR is influenced by their age, body mass, lean body mass, gender, hormones and obviously a big determinant of the mentioned factors is genetics.
EAT (Exercise Activity Thermogenesis) - This is the energy used to fuel our planned physical activity. When we exercise, it requires a large increase in muscle contraction, and this muscle contraction uses up energy. EAT includes things such as resistance training, running, cycling and football.
TEF (Thermic Effect of Food) - When we eat food, the energy sources within that food (carbohydrate, fat and protein) need to be digested, absorbed and assimilated in order for the energy within those food sources to be utilised by our body. However, this process actually requires energy, and this is known as TEF.
Each macronutrient costs the body a different amount of energy when we eat it. They are as follows:
NEAT (Non-Exercise Activity Thermogenesis) - This is the energy used during day to day activities excluding eating, sleeping and planned exercise. Again, the energy is needed to fuel muscle contraction, but usually at a lesser rate than exercise. Some examples include typing this post, taking the stairs and washing up. This is an area people tend to undervalue when trying to lose weight. Studies have shown NEAT to account for up to 30% of daily energy expenditure in certain individuals. That's huge! Rather than cutting back more on nutrition (which is essential for our bodies to function, grow and repair), or trying to add in extra volume to your training through cardio, increasing NEAT can be an effective and relatively easy method to achieve your calorie deficit.
Energy input is only comprised of one thing, and that is energy consumed. However, this can be broken down into calories that are consumed through food and drink. This is a pretty basic concept that we don’t believe needs further explaining.
If our energy intake (food & drink) is equal to our energy output (RMR, TEF, EAT & NEAT), our body weight will then be maintained.
Negative Energy Balance (aka calorie deficit)
When we are in a negative energy balance, our energy output (RMR, NEAT, EAT & TEF) is greater than our energy input (food & drink). It is important to note that when our bodies are in a negative energy balance, our body they will always find a way to survive. That is, a negative energy balance doesn’t mean that there is suddenly not enough energy available to allow basic bodily functions to occur, such as breathing. Our fat and muscle can actually be broken down to produce ATP (energy). This is why weight loss occurs in a calorie deficit. Our body realises that it is not getting adequate energy from our food & drink intake, so it then gets it from stores within our body. This is an extremely impressive survival mechanism.
Positive energy balance (aka calorie surplus)
When we are in a positive energy balance, our energy input (food & drink) is greater than our energy output (RMR, NEAT, EAT & TEF). Again, it is important to note that when our bodies are in a positive energy balance, our body has survival in mind. That is, a positive energy balance is an opportunity that will not go to waste. Our body will use this energy to build both fat and muscle, which can then be used in the future for any times that we are in a negative energy balance. This is why weight gain occurs in a calorie surplus.
An energy balance example
A scientific lab has done many tests on Bob over a week period and calculated that Bob’s energy output is 2500 calories. This is broken down into the following.
RMR: 1400 calories. This is how much energy Bob's body needs to stay alive, when in a completely rested state.
EAT: 600 calories. This is how many calories Bob burns when he plays football twice per week.
TEF: 250 calories. Bob burns 250 calories digesting, absorbing and assimilating his food.
NEAT: 250 calories. On a typical day, Bob expends 300 calories
Therefore, to maintain weight, Bob needs to eat 2500 calories. If he eats below or above this, he will lose or gain weight, respectively. We will get on to how many calories above and below his predicted maintenance Bob (and you) should eat for different situation in section **
NOTE: Even when done in a scientific lab, calculating someone's energy expenditure is an estimation. It is impossible to predict physiology to 100% accuracy, and someone's energy input and output will fluctuate daily by quite a large degree.