Episode 4: Macronutrients and Calories
- EBE
- Jan 6, 2020
- 5 min read
Updated: Apr 16, 2020
Yay we have made into what makes up our food. We now know more about ourselves and the research that helps us understand food better. With that perspective let's start with how we get calories into our body.
Macronutrients (aka Macros) are the form in which we get calories. There are no calories in micronutrients. The term macronutrients includes the subcategories: fats, carbohydrates, and proteins. Fats, proteins, and carbohydrates are present in various proportions in our foods and they are the building blocks of our diet that add up to become our overall calorie intake. 1gram (g) of protein = 4kcal, 1g of carbohydrates = 4kcal, and 1g of fat = 9kcal. When you see that a food has 10g of protein then you know that 40kcals of that that food came from protein. On a nutrition label you will see things listed as calories or Cals instead of kcals. "What is the difference between calories and kilocalories? The "calorie" we refer to in food is actually kilocalorie. One (1) kilocalorie is the same as one (1) Calorie (upper case C). A kilocalorie is the amount of heat required to raise the temperature of 1 kilogram of water one degree Celsius. Please visit USDA's Food Composition Laboratory for additional information."
Each of us has a calorie requirement, meaning we need to eat at least X amount of calories each day to live. Think of food as the wood that you have to put in the fire to keep the fire going. The food we eat is turned into energy such as the heat we produce to keep ourselves warm and the substances that let us use our muscles to move around the world. There are 5 important terms we are going to talk about when it comes to the calories we need and burn each day:
Let's get into all the components of maintenance calories. In order to maintain your weight you need to eat enough to cover the four ways in which we use calories in our body. Maintenance calories = BMR + NEAT + Exercise + TEF. If your weight is the same everyday you are eating maintenance calories. If you are gaining weight you are eating above your maintenance. If you are loosing weight you are eating less than your maintenance calories.
Our Basal Metabolic Rate (BMR) = the calories we need to maintain living, not including all the things we do in life, just to exist, think of this as the calories you would need if you were to just lay in bed for 24 hours. Our BMR is determined based on our Fat free mass. Fat free mass = everything in your body that isn’t fat or water. The most metabolically active tissues are your organs like your brain and your liver, your bone, and your muscle. Your BMR is usually determined by your height and weight based on an assumed amount of body fat, if you get your body fat and water % measured with something like a DEXA scan you can more accurately estimate your BMR. Your BMR goes down as you age because after you are done growing you are no longer building your body you go into maintaining your body. As we age our bones get less dense and we loose muscle and this also decreases our BMR. When your BMR changes occurs between the age of 18-30years of age. You might have experienced this as a weight gain without a change in activity or diet. You can protect your BMR by maintaining your bone density and muscle mass. If you have been inactive and your BMR has decreased you can increase it at any age by actively building muscle through exercise. This is why exercise is more beneficial than just the calories burned in any given session, it has lasting effects on your BMR. Similarly when you diet your BMR usually also decreases because it is not conducive to survival for your body to retain your entire muscle mass while reducing your fat mass. Your muscle demands a lot of calories so your body will decrease your muscle while also decreasing your fat mass to adapt to your new lower calorie intake. This is the foundation of yo-yo dieting. The lower BMR at the end of a diet sets the person up for more and rapid weight gain because muscle was also lost. You can minimize the amount of muscle mass you loose when in a calorie deficit - to do this correctly I recommend you reach out to a registered dietician because it entails figuring out what the minimum calorie deficit needed to loose weight while also continuing to exercise.
NEAT, Which is Non-Exercise Activity Thermogenesis. NEAT is essentially any movement you make with your body that is not directly exercise so when you are sitting in class and tapping your foot you are experiencing NEAT when you are walking your dog around the block you’re experiencing NEAT when you are cleaning your house you are experiencing NEAT. We can increase NEAT pretty simply, we just move our body more.
Examples for increasing your NEAT:
standing at your desk
walking instead of driving
taking the dog on longer walks
getting up every hour to stretch
What makes NEAT different from exercise is that it is scattered throughout your day and it is low intensity, meaning it is not difficult. Note that NEAT is something we adapt to quickly, meaning if you have been walking 10,000 steps everyday for years you are not getting the same calorie burn today that you had when you first started. This is one of the reasons why it helps to have lots of different forms of NEAT that you varying throughout your life (sometimes you stand, sometimes you walk etc.)
More info for NEAT
Thermogenic Effect of Food (TEF) and that is where our macronutrients start to get nuanced. TEF is essentially how inefficient is our body at utilizing the food that we eat, because it takes energy to digest food. TEF does not make celery calorie free, no it doesn't work that way but as you will see when we get into the details of each macronutrient I will talk more about TEF and how it leads to some of the results we see in studies.
Exercise: Last and the most obvious way to burn more calories is through exercise. Most people focus on exercise in order to change their weight. The Center for Disease Control (CDC) recently updated their guidelines (recommendations) for the amount of exercise each person needs each week. They determined that at least 150 minutes of moderate activity (cardio/aerobic activity) each week + 2 sessions of strength training each week is the amount of exercise that improves your health. The American Journal of Preventative Medicine published that the minimum amount of exercise to prevent disability within 4 years = 1 hour per week. Meaning, start from where you are at, if you are inactive aim for 1 hour of moderate to vigorous activity per week (activity where you are breathless). If you are already active keep your activity level above 150min = 2.5 hours of moderate intensity activity (jogging) + 2 resistance training (lifting weights) per week.
Image: CDC Recommendations https://www.cdc.gov/physicalactivity/basics/adults/index.htm
Now that you know what makes up calories and how we use calories we will be getting into each type of macronutrient in the following episodes.
The big take-aways from this episodes:
- what are the categories of macronutrients
- what are calories
- why do I need calories
- how do I burn calories
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