I know I’ve written about calories a number of times before, but I want to revisit them now. In a previous post (Not All Calories Are The Same) I write about how the source of calories do matter, something I still believe. Now, I want to really discuss whether the number of calories really matter.
The basis of most weight loss plans and diets is that:
- Calories In > Calories Out = Weight Gain
- Calories In < Calories out = Weight Loss
For weight loss, a lot of what I see recommends 1200 – 1600 calories a day. It seems a little odd that given how different our bodies are, such a simple and set formula would work for everyone, doesn’t it?
What Exactly is a Calorie?
To start, let us revisit what a calorie really is. Basically, in terms of chemistry and physics, a calorie is how much energy is required to heat 1g of water by 1°C. This may seem rather abstract and like some kind of experiment that happens with beakers in labs. Essentially, a calorie is a unit of energy (we could use Joules if you prefer since 1 calorie = 4.184 Joules) and our bodies need energy to do things like digest, move, think, etc.. So far, it all makes sense that if you take in less energy than you expend, you would lose weight. That’s all fine and dandy, but what I really take issue with is this whole “1200 – 1600 calories to lose weight” thing.
What Happens to the Calories?
Let’s say you just finished a meal, for now it doesn’t matter if it was a fast food burger or some hyper healthy superfood packed meal. Now that you’ve put those calories into your body your metabolism is what does the work. Your metabolism is what converts food (potential energy) into energy that can be used by the body (kinetic energy). Even while you are sitting and reading this post, your metabolism is in action helping you breath, circulating your blood, and regulating your hormones. This “no-effort-added” metabolism is known as your Basal Metabolic Rate (BMR). There are several factors that affect this metabolic rate:
- Your body size and composition: Muscles require a lot of energy, even at rest. The more muscle you have the higher your BMR will be.
- Your biological sex: Women naturally store more fat because men never have to worry about growing a fetus for 9-months.
- Age: As we get older lean muscle mass decreases 
Aside from this BMR, one of the major contributors to your overall metabolism is your Total Daily Expenditure. This is how much energy you use during exercise per day. Now, this exercise doesn’t just mean hitting the gym, it means any sort of movement while you’re not at rest. It counts things such as cleaning your house, taking the stairs, walking to work, etc.
So, that meal you just ate gets converted into energy for your body. The efficiency of that conversion depends on your BMR. Your body will also require energy for your TDEE, that meal you just ate will also serve as fuel for that.
How do I Figure Out What My Body Needs?
Alright, this is where I start to take issue with calorie counting. So far, everything sounds pretty good, you eat food for energy and your metabolism converts that food into energy to be used by your body for basic processes and physical activity. Sweet. But lets say I wanted to lose some weight. How exactly do I figure out my BMR and TDEE to achieve that?
Your BMR is determined by the Harris Benedict Equation (HBE)… or the Revised Harris Benedict Equation (RHBE). (Already were off to a good start). Since the HBE is most common we’ll go with that one. Here is what it looks like:
For men (Imperial – lbs/inches/yrs)
BMR = 66 + ( 6.2 × weight ) + ( 12.7 × height ) – ( 6.76 × age )
For Women (Imperial – lbs/inches/yrs)
BMR = 655.1 + ( 4.35 × weight ) + ( 4.7 × height ) – ( 4.7 × age )
Once you calculate your BMR you can calculate your TDEE as:
Sedentary or light activity : BMR x 1.53
Moderate activity (running 1hr daily) : BMR x 1.76
Vigorous activity (swimming 2hrs daily) : BMR x 2.25
Alright, so if I, a 24yr old 5’5 166lb female(yes, I am technically “overweight”, don’t get me started on BMI) who is “moderately” active, my BMR is 1569.9cal and TDEE is 2763cal.
If I Want to Lose Weight, I Follow These Numbers?
To start, I just want to say that I tried a number of online BMR & TDEE calculators online, and none of them came up with these numbers, some were up to 400cal off on my TDEE. That’s not too surprising since “light”, “moderate” and “vigorous” are all pretty subjective and ambiguous. Suppose you run 1hr at quick pace for a week but the following week you run for 1hr at a slower pace because you decided to try a new route with nicer scenery that you were enjoying. Well, your TDEE is going to be different, even though you would have still multiplied your BMR by 1.76.
Also, what about body composition? As was mentioned earlier, muscle burns more energy than fat does (even at rest). Let’s say we have a body builder who’s trying to lower their body fat before a show and an overweight person who is trying to get to a healthy weight. They’re the same height, sex, and weight and are both giving it their all 7 days a week (don’t actually try this at home). For starters, 1lb of muscle burns 6.5 calories per hour and 1lb fat burns 1.2 calories per hour . Right off the bat, the BMR of the body builder is going to be much higher.
Calorie Counting is Ineffective
I know that header is likely to give me some not so pleasant response. But hear me out. I will agree that counting calories has helped a lot of people lose weight. Although I strongly disagree with it as an over all practice for a number of reasons:
- Are you really going to count calories your whole life
- It doesn’t encourage eating for health. People look for the low cal options but last I checked chicken breast and veggies are much healthier for you than Coke Zero.
- It fosters and unhealthy relationship with food and eating.
- Everyone’s body is different. The formulas may be in the ball park, but they aren’t set in stone.
If you are looking for an effective way to lose weight here are some principles to follow:
- Understand cues from your body. Learn the difference between eating for hunger or eating for boredom.
- Rely on real food. Focus on fruits, veggies, lean meets, whole grains. Reduce the amount of processed food you buy and consume.
- Move. The benefits of physical activity aren’t strictly related to weight loss. Regular exercise improves mood, cognitive ability, sleep, and a number of other things
- Sleep. Our society tends to praise those who say they’ll sleep when they’re dead. Well guess what, if you don’t sleep enough you’ll probably find yourself dead sooner. Sleep is important for regulating hormones and for repairing the body.
If you made it this far, thanks for reading! I hope you enjoyed this post.