Calorie counts matter. Too many and you gain weight. Too little and you may put your body in danger. Yet, there are some inherent problems with the advice to just count calories for weight maintenance. Understanding how calories differ can help you better understand why dieting doesn’t work; why you and a family member or friend could both follow the same ‘diet’ but obtain entirely different results, and how to find help if you need it.
Some think calories are all that matter and you should track everyone you ingest and burn (we were told that for years after all). Others think calories do not matter and that calorie counting is in fact detrimental. Let’s see if there’s a happy medium.
How Calories Differ
In last week’s post, I touched a bit on nutrition and what foods to consider when striving for eating healthfully. Eating the healthiest foods leads to better fuel for our bodies. Food’s macronutrients, protein, carbohydrates, and fat, as well as alcohol, contain Calories (energy) that is transferred to us as the body digests it.
Your body needs this energy for:
- Basic body functions while our body is awake and at rest
- Basal metabolic rate (BMR)
- Resting metabolic rate (RMR)
- Movement and physical activity, from fidgeting to structured exercise
- Exercise activity
- Non-exercise activity thermogenesis (NEAT)
- Food digestion, absorption, and transport
- Thermic effect of feeding (TEF)
The relationship between our energy intake and energy expenditure is referred to as energy balance, and it is what determines our body weight and our overall health.
An energy imbalance in either direction can lead to not only a change in our body weight and appearance, but also to dysfunction in our metabolic system, reproductive system, cognitive systems, and recovery mechanisms. Prolonged dysfunction in these systems can lead to serious diseases and an inability to function properly.
A calorie is a calorie…
but the utilization of calories within our body differs based on the type of food from which it is derived. Further, how our bodies handle calories in versus calories out, varies from person to person.
While the reason you gain weight is that your ‘calories in’ exceeded your ‘calories out’ there may be more to the story. It’s not always as simple as overeating or exercising too little. It’s also what your body does with the calories you ingest.
The number of calories you obtain from food depends on how many you absorb, influenced by:
The energy needed for digestion of food.
It takes more energy to digest protein than it does fat or carbohydrates. I told you last week that protein and carbohydrates provide four calories per gram, fat provides nine calories per gram, and alcohol provides seven calories a gram. That isn’t the whole truth. Outside of the body, the number of Calories contributed by the macronutrients and alcohol, on average, look more like the amounts below, but once processed in the body we receive the amounts mentioned above to use for energy.
- Fat – 9.44 Calories per gram
- Protein – 5.65 Calories per gram
- Carbohydrates – 3.94 to 4.18 Calories per gram
- Alcohol – 7.09 Calories per gram
In other words, a person uses approximately 10% of their daily energy expenditure digesting and absorbing food, but this percentage changes depending on the type of food you eat.
Protein requires the most energy to digest – 20-30% of total calories in protein eaten goes to digesting it, followed by carbohydrates at 5-10% and finally fats at 0-3%.
Thus, eating 100 calories from protein provides you a net 70-80 calories. Carbohydrates would leave you with a net 90-95 calories per 100 calories, and fat would give you a net 97-100 calories.
Note: It takes less energy to digest and absorb processed food than it does to digest and absorb whole foods. Thus, 100 calories of processed food ends up providing more net calories than 100 calories of whole food.
How food is prepared.
Cooking, chopping or blending food generally provides more available calories for absorption, that food labels don’t always account for as it now takes less energy for you to digest.
Individual absorption rate and function.
We absorb calories uniquely and variably based on our individual gut bacteria. Yes, your gut flora really is a thing and depending on which type you have predominately – Firmicutes bacteria or Bacteroidetes – you’ll absorb more or fewer calories per day.
Nutrition label accuracy.
This is a biggie as there is no way to know for sure the caloric content of food without testing everything you eat in a lab. Legally, they are five different methods for food companies to use when estimating calories, so nutrition labels can vary up to 20% from the actual calorie content of the food. Restaurants are often more imprecise.
So it’s hard to really trust that the calorie numbers – or any numbers – you see on food packages are accurate because the way they are calculated if they’re calculated at all, is surprisingly ambiguous. Then, once the food is cooked, or chopped, or blended, the amount of energy available for digestion and absorption changes. Not to mention what happens once that food enters your body.
How Calories Differ On the Other Side of the Equation
Once calories are ingested, we get to burn them. The number of calories you burn is influenced by:
Those items mentioned earlier – Basal metabolic rate or BMR, Resting metabolic rate or RMR, Exercise, Non-exercise activity thermogenesis or NEAT, and Thermic effect of feeding or TEF – and additional items such as:
- Muscle mass vs. fat mass – Muscle burns a little more energy than fat
- Organ size – Larger organs burn more energy
- Body temperature – Higher temps burn more
- Genes and Epigenetics – A single variation in a gene or what our mothers ate when pregnant with us can affect the number of calories we burn per day
- Sleep – Not enough sleep one night can cause you to burn fewer calories the next day
- Hormones – A woman’s RMR is affected by her cycle
What you eat, and how much you eat of it.
When you overeat, your metabolism will increase. Some people, however, are better at this than others. So while you may over eat the exact same amount as your friend or spouse, you may differ in the amount of weight gained.
Also, as discussed above you will burn more energy digesting protein, followed by carbohydrates, and then fat.
If you’ve previously been very overweight or obese, your metabolic rate may not be as efficient as equations predict, due to adaptive thermogenesis.
Calorie burn estimates differ.
Just like there are different ways to calculate calories in food, there are various ways to approximate calorie expenditure.
The most accurate – and most expensive so rarely used – method has a margin of error just over 3%. But the method used 99% of the time to provide burn estimates has a margin of error up to 45%! So that fitness tracker you use is likely off 10 – 30%.
So Calorie Counting Is Out?
Perhaps, although while calorie counting is not an exact science, I think it can still be a useful tool used on occasion.
How calories differ going in and out is one part, but there’s also personal preference. If you enjoy tracking or if it helps you stay on aim towards your goal then use it. Just be careful not to become obsessed with counting calories because as you can see, it’s not a perfect system.
Like any other tool in your toolbox, you needn’t use it every day, but when trying to figure out a weight loss or gain issue, it may be a valuable resource to start with to help determine what might be amiss.
Method For Determining Calories Needed
We start with calculating our resting metabolic rate or RMR and then adjust it based on our activity level.
There are a few different methods for calculating your rate, the Harris-Benedict Equation for RMR, the Owen Equation for RMR, and the WHO/FAO/UNU, but one proven to be especially useful is the Mifflin- St. Jeor equation.
For women: RMR = (9.99 x weight in kg) + (6.25 x height in cm) – (4.92 x age) – 161
For men: RMR = (9.99 x weight in kg) + (6.25 x height in cm) – (4.92 x age) + 5
Your weight in kilograms = weight in pounds x 0.45359237
Your height in centimeters = height in inches x 2.54
Once you determine the RMR, multiply it by the appropriate activity correction factor below:
1.200 = Sedentary – little or no exercise
1.375 = Light activity – light exercise/activity 1 – 3 days per week
1.550 = Moderate activity – moderate exercise/activity 3 – 5 days per week
1.725 = Very active = hard exercise/activity 6 – 7 days per week
1.900 = Extremely active = very hard exercise/activity and a physically demanding job
Female Example: 140lbs, 5’3″, 35 years of age
140lbs x 0.45359237 = 63.50 and 63in x 2.54 = 160.02
(9.99 x 63.50) + (6.25 x 160.02) – (4.92 x 35) – 161
634.365 + 1000.125 – 172.20 – 161 = 1301.29
1301.29 * 1.550 = 2016.999 or 2017 calories per day to maintain current weight
Male Example: 180lbs, 6′, 30yrs of age
180lbs x 0.45359237 = 81.65 and 72in x 2.54 = 182.88
(9.99 x 81.65) + (6.25 x 182.88) – (4.92 x 30) + 5
815.684 + 1143 – 147.60 + 5 = 1816.08
1816.08 * 1.550 = 2814.924 or 2815 calories per day to maintain current weight
To lose weight, you need to create a 3500 calorie deficit per pound. Do this via eating fewer calories, burning more calories through exercise, or a combination of both (my preference).
What else can you do?
Focus on increasing your daily movement activities and try out the hand measurement system for food portions shown below.
If you are looking to lose weight, these additional factors have shown to be of assistance in attaining a negative energy balance:
- Eat High nutrient dense / Low-calorie dense foods – veggies, fruits, lean proteins, whole grains, etc.
- Ingest dietary protein
- Eat nuts regularly
- Incorporating super shakes or green smoothies in as a meal
- Drink Green tea
- Stay hydrated
- Ingest dietary fiber
- Exercise regularly
- Obtain adequate sleep
- Have a positive social support system
- Avoid refined carbohydrates
I’d love to hear from you now. Did you previously know how calories differ? Has or does counting calories work for you? What other questions do you have about nutrition? Was this post helpful?
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