This is Part 1 of a 2-Part series. Here we’ll introduce some general nutrition principles and in part 2, we’ll explore application & misapplication for a better understanding of the nuance & individualistic nature within nutrition.
Calories In vs Calories Out (CICO)
This is a widely accepted, universal principle. One that is relatively easy to understand. However, when taken out of context, or applied without thought to nutritional periodization, may create unfavorable results.
A calorie is a unit of energy. Scientifically speaking, a calorie is a unit of energy defined as the amount of heat needed to raise a quantity of water by one degree of temperature. But for our purposes we can think of it as simply a unit of energy that our body ingests & expends.
We consume calories through food & beverages (Energy/Calories IN). And we expend calories through multiple pathways including physical activity, metabolic processes & daily bodily functions that keep us alive (Energy/Calories OUT).
The total calories we ingest vs. the total calories we expend determines whether we gain, lose, or maintain our weight.
When calories IN are less than calories OUT = We lose weight (aka Calorie Deficit) because our body is expending more calories than it is getting from our diet.
When calories IN are approximately equal to calories OUT = we maintain our weight*(aka Maintenance) because the calories our body is expending day to day is approximately equal to the calories we get from our diet.
When calories IN are more than calories OUT = We gain weight (aka Calorie Surplus) because our body is expending fewer calories than it is getting from our diet.
These principles are collectively known as the Calories in, Calories Out or CICO Equation.
*note that our weight (as noted on the scale) will fluctuate day to day. This is normal & not considered weight loss or gain when looking at data day to day. However, when this data changes over time (at least 2 weeks or more), trending up or down, that could be considered weight loss/gain.
When we talk about weight loss or gain, the term “weight” includes both Fat Free Mass (muscle & body tissue such as bones & organs) and Fat Mass (fat). The amount of FM & FFM gained or lost is dependent on numerous factors including but not limited to: protein intake, resistance training/weight lifting, severity of calorie deficit or calorie surplus, duration of deficit or surplus, genetics, etc.
Total Daily Energy Expenditure (TDEE)
Our Total Daily Energy Expenditure (TDEE) is the total energy that our body expends each day. For our purposes, we can think it it as the total calories our body uses each day - the “energy OUT” part of the CICO equation.
What’s important to know about TDEE, is that it is made up of 4 components, each of which accounts for a different amount of calories out.
Basal Metabolic Rate (BMR) - The total calories burned by our body at rest (not eating or moving). Activities would include, breathing, heartbeat, blood circulation, cell/tissue repair, etc. Basically everything except movement & the digestion & absorption of food.
BMR is influenced by many factors including: body size (weight & height), total lean mass (muscle), total body fat (fat mass), age, sex, genetics, diet history, illness/injury, medications, etc. BMR accounts for ~ 70% of our TDEE.
Non-Exercise Activity Thermogenesis (NEAT) - The calories burned by our body during non-exercise related movements like: fidgeting, standing, walking to the bathroom, cooking, cleaning, etc. NEAT accounts for ~15% of our TDEE.
Thermic Effect of Food (TEF) - The calories burned through the process of digestion & absorption of food/nutrients. Of all 3 macronutrients, protein has the highest TEF, meaning it requires the most calories to break down & absorb 1 gram of protein when compared to carbs & fats. TEF accounts for ~10% of our TDEE.
Exercise Activity Thermogenesis (EAT) - The calories burned through intentional exercise - biking, swimming, crossfit, strength training, running, etc. EAT accounts for ~5% of our TDEE.
Most people are surprised by how low the percent of calories from exercise are in the grand scheme of things. This is important to note because our society has a tendency to glamorize workouts & pressure folks to continually increase their exercise without recognizing the stress & strain it can have on our bodies.
So if you were aiming to increase your TDEE, rather than simply adding on extra exercise, we often suggest decreasing our time at rest (being sedentary), increasing our NEAT by increasing our steps, and by eating higher protein.
When combined, those 4 components determine the total energy we expend each day. Another way to think about this, is that your TDEE would also represent your Maintenance Calories - the calories you would need to eat each day in order to maintain your weight (neither losing or gaining weight).
Metabolic Adaptation
Our bodies are biologically designed to be extremely smart. And we’re not just talking about mental or cognitive intelligence. By design, our bodies are made to be scanning the environment (both internally & externally) for stress & threats and adapting to keep us alive. We are built for survival & that is our body’s baseline instinct.
Under stress & threat, the “extras” like fertility, body composition/leanness, etc. are of much lower priority. For that reason, when we are highly stressed, it becomes harder to achieve overall health, much less the gym PRs or lean body composition that so many people are seeking.
The body’s ability to adapt to these stressors is quite remarkable, but unfortunately doesn’t always have the outcomes we want.
For example, when we are pursuing weight loss in a calorie deficit, our body recognizes that the amount of food ingested is not equal to the amount of energy the body expends. Therefore, over time, our body will adapt (via hormonal changes, downregulation & decreased metabolism), to offset that energy deficit. Essentially, our body adapts to become more efficient, so it can operate with fewer calories.
In this context, metabolic adaptation is often referred to as a “plateau” in weight loss progress. Because our body has downregulated the components of TDEE to match that of our incoming calories. And thus, what was once a calorie deficit, now becomes a new calorie maintenance. Which is why… we can’t diet forever!!
There is more nuance to this process, but for our purposes, the takeaway is this: Our bodies are smart & will adapt to changes in our energy in & energy out in order to maintain homeostasis & enable us to survive.
Metabolic Adaptation is one of the nutrition principles that is most often misapplied for the reason listed above - We don’t acknowledge the body’s ability to adapt!
Stay tuned for the a future blog, where we will dive into some of the considerations of Metabolic Adaptation & how to make the most of your dieting efforts.
There are many nutrition principles that govern our physiology & therefore our physical abilities & appearance. However, the 3 principles listed above represent some of the main factors influencing our goals & are often the most overlooked or misunderstood.
We will touch on other nutrition principles in later blogs. But for now, see if you can apply these principles towards your nutrition & stay tuned for our future blog on application & misapplication of these principles!
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Nicola