fruits, fresh, basket

Here it is! The one, absolutely, definitely, positively, 100% certain way that you’ll lose weight.  There is no doubt about it, if you follow this method, you will lose weight. Is it Keto? NO! Is it Carnivore? NO! Is it Vegan?! NO!! OK. OK. I’ll get right to it. I swear…

The Science

There are many interesting theories out there about weight loss. About some different mechanisms that might be at play involving fructose vs sucrose, fats and proteins being prioritized over carbs to get the body in a state of ketosis, and many many others. And those theories deserve to be studied. However, I told you I was going to give you the one, foolproof way to lose weight, and I’m not lying. It’s valid no matter which diet you’re on. And it is based in science. Real, pure science. Here we go:

*You have to expend more calories than you consume in order to lose weight*

If I was better with technology, I would have made that sentence glow and pulsate on the screen. That’s it. That’s the science. If you use more of your energy source (calories) than you take in from food, you will lose weight. It’s not about plant vs. animal products. It’s not about whole grains. It’s about energy balance.

Fad Diets

All fad diets, if the authors of the diets are being truthful, are based around the principle of calories in vs calories out. If someone loses weight, it is because of this simple, one sentence principle. Let’s take a look at a few different fad diets and see how they all apply the CICO principle.


This is going to be a very basic description, as this diet relies on some pretty in-depth physiology principles. But in the basic keto diet, the goal is to get your body to use ketones instead of glucose for energy. So, you eat a lot of foods that will make this happen. Ketones are a byproduct of breaking down fats and proteins for energy, when glucose is in short supply. The reason why it works for weight loss is that proteins, fats and carbs all have different properties. A property of proteins and fats is that they are more satiating than carbs. Meaning when you eat 10 grams of protein and 10 grams of carbs, you’ll feel more full from the protein. This diet, like many of the others, operates under an exclusionary principle, by restricting a certain food group, you are left with fewer choices. In this case, the choices are high protein and high fat, which will fill you up with less calories and thus will often lead to expending more calories than you consume…that is unless you overpower your hunger sensors and eat past the feeling of being full.

Intermittent Fasting

Intermittent fasting is just as the name suggests: eating for a period and fasting for a period. There are numerous ways to do this. Popular methods are to eat one meal a day (OMAD) or to eat all of your calories in an 8 hour window and fast for the other 16. There are other methods,
but those are two of the biggies. Intermittent fasting works well for weight loss because you are restricting the time in which you consume calories. Any time that you’re not eating, you are in a negative energy balance. This is another diet based on the exclusionary principle, but in this one you exclude certain time frames rather than certain food groups. The caveat to this, and all other diets, is that when you do eat, you need to be careful that you don’t overcompensate and eat more than you usually do!


“If it Fits Your Macros” is another popular diet trend. This is one diet that is probably the closest to being honest about its aim and how it works. In general, IIFYM has the person count his or her macronutrient levels each day. Macronutrients are carbs, fats and proteins. These are the substances in food that provide us with energy in the form of calories. Compare these with micronutrients, which do not provide calories, but are also very important (a topic for another day). The person starts off by calculating his or her own specific calorie requirements to maintain their weight. Then, all the person has to do is eat less than that amount of calories each day and the weight will start to decrease.

How To Actually Implement The Science

Hopefully at this point the reader has accepted the science of weight loss and is now looking for how to use said science to his or her advantage. Before getting to the method though, I want to briefly say this: health is different from weight. The following is going to apply for how to lose
weight, not how to be healthy. Those two often go hand in hand, but there are differences, and those will be covered in a future post. Ok, here we go.


We touched briefly on macronutrients above, but essentially, macronutrients are the parts of food that provide calories. Broadly, they are fats, carbohydrates, and proteins. Each of these has different properties, but in terms of strictly calories, protein and carbs have about 4 calories per gram, and fats have 9 calories per gram. So basically, the calories from these nutrients are summed up each day and compared to the amount of calories needed for the person to maintain his or her weight. If the calories taken in are less than that number needed to maintain weight, and the person continues to consume less than that number on a daily basis, he or she will lose weight. The opposite is also true. (it should be said too, that as a person loses weight, the amount of calories needed to maintain weight will lessen.)

Calculating Calories Needed to Maintain & Lose Weight

Many healthcare practitioners can provide you with a method or test to calculate how many calories are needed to maintain your weight. This value varies significantly from person to person based on many factors. There are also services on phone apps and websites that can give a rough estimate of caloric need.

But basically, once you arrive at this number, you just eat a little bit less than it each day. A good place to start to slowly and safely lose weight, is to write down all of your meals from a day and calculate the calories based off of the food labels. Then, write this number down each day
for a week. The next week, try to eliminate 100 calories each day. Then the following week, try to eliminate 200 calories each day. Once you get up to 500 calories eliminated a day, you will be eliminating 3500 a week. The number 3500, coincidentally, is the amount of calories stored in a pound of fat. (this is purely used as an example and not intended for specific medical advice.)

Calories “Out”

We’ve discussed calories in vs calories out mostly from the perspective of how to take in less calories. And there is a reason for that: it is really, really hard to lose weight from simply changing exercise habits.

Don’t get me wrong: exercise is incredibly important for a healthy, active life. But in terms of just weight loss, it’s not going to be realistic to only change exercise habits and expect to lose significant weight.

A couple of cookies can add up to 200 calories pretty quickly. It takes the average person a couple of hours to burn off 200 calories through exercise.

How To Keep It Off

Now onto the second part of the title: how to keep it off. We’ve talked about how to lose the weight and the science behind it, but here comes the hard part.

The Quicker The Worse

Now you may be thinking, “the more I eliminate, the quicker I’ll lose weight!” While this may be true, there are other factors that will hinder your progress, and this is generally a dangerous way to go about weight loss. Eliminating too many calories too quickly can cause breakdown of other tissues besides just fat (the stuff we want to lose). Muscles, bones, and other structures can be broken down by your body if your body senses that you are starving. This can lead to injury and failure to reach your goals in the long run.

Slow, sustainable weight loss is the name of the game. Aiming to lose just 1-2 pounds a week is a great goal. Too much more than that, and you can become frustrated, irritable, and worst of all: hungry.

Set Realistic Goals & Forgive Yourself

Everyone (myself included) wants to reach their goals immediately. We are in an age of being able to get most things as soon as we think of them. One-day package delivery, immediate email replies…it’s definitely an era of convenience. However, when it comes to health, our bodies have not adapted to the technological changes we have available. Our bodies change slowly, methodically.

This is why it’s so important to be realistic with your goals. If you’re not sure what’s realistic for you, talk to your doctor, physical therapist, personal trainer, dietician or someone in the field that is qualified to help you.

Also, you may not reach your goals on the first try. You may fail. There may be a month where you feel like the world is crumbling around you and the last thing you want to do is exercise and eat well. That’s ok. Forgive yourself. Take a breath. And get right back to reaching those goals.

Bottom Line

That was a lot of information. If you stuck it out, great job! If you started reading then thought, “let’s get to the point…” that’s also ok, and we’re almost done. Also, If you saw this title and got excited, then scrolled to the bottom to get the answer: here you go: calories in vs calories out.

Weight loss is not easy. It’s even harder to keep the weight off after having lost it. It takes a sustained effort and a lot of the time, it can feel like the forces of the world are working against you.

But if you’ve determined that you are going to lose weight. If this is the year. Throw out all of the quick fixes. Toss all the junk science out with it. Think about why, deep down you want to lose weight. Keep that goal in mind. And remember the science: if you eat a little bit less, and move a little bit more, you will lose weight. Good luck!

Disclaimer: The information provided in this post or anywhere on is no substitute for an evaluation by a licensed healthcare provider. Always consult with your doctor before beginning any exercise or diet plan.

0 replies

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *