Are All Calories Created Equal?

Many “health professionals” like to argue that calories don’t matter when it comes to fat loss. Instead, they suggest that the only thing that matters is food quality. They say things like “there’s no way that you really think that 100 calories from a brownie is the same thing as 100 calories from kale.” It’s unfortunate because these types of simple statements sound very attractive and “make sense,” right? There’s no way that eating brownies is as healthy as eating kale or other whole unprocessed foods. However, that’s not the way we should be discussing calories.

We can all agree that eating vegetables is nutritionally better for you than eating brownies. However, the issue is that we're conflating calories with the nutritional quality of food, which are two completely different things. It doesn’t have to be calories or food choices. The reality is that both variables are related, and both matter for weight loss. One of the reasons this confusion exists is that people don’t really understand what a calorie is.

What is a calorie?

A calorie is not a physical thing, it is simply a unit of measurement. For example, we measure mass and distance with units of measurement like pounds and meters. Calories are no different; they’re just a unit of measurement for the energy of food.

Let’s say you eat some food that contains 100 calories. This just means that your body received a certain amount of energy equivalent to 100 calories. By definition, calories have absolutely nothing to do with the quality or the nutritional value of the food that you eat. It’s simply a way to measure how much energy that food provides.

Why do calories matter for fat loss?

It comes down to a concept that we call energy balance, which is the relationship between how much energy you get from the food you eat and how much energy your body expends.

Your body requires a certain amount of energy every day because your body expends energy to keep you alive, maintain basic organ function, keep your heart beating, regulate your body temperature, and move around. If you consume less energy from your diet than the amount of energy that your body expends on any given day, your body isn’t receiving the amount of energy it requires from your food. (If you want to learn more about this topic, check out the article Here's What Really Matters for Fat Loss).

So, what happens?

Well, your body still needs to get that energy from somewhere, so it's going to tap into stored energy sources like body fat to get the required energy, which results in weight loss. So, weight loss is just a byproduct of your body metabolizing fat to make up for the energy it’s not getting from your diet. The exact opposite is true for weight gain. If you eat more energy than your body requires on any given day then your body is not going to waste that excess energy but instead, it's going to store it as body fat, which will result in weight gain.

Calories determine weight loss or weight gain

The process of gaining or losing weight is independent of the actual foods you choose to eat. You can theoretically gain weight just by eating healthy foods like apples and spinach, although it's going to be very difficult because those foods don't contain a lot of calories.

At the same time, this also means that you can lose weight by eating "bad foods" like brownies and cookies if you simply don’t eat that much.

Don't believe us? Check out this article on the "Twinkie Diet".^[1] Mark Haub, a professor of nutrition at Kansas state university lost 27 pounds by eating strictly ultra-processed foods like chips, sugary snacks, and cereals by tracking his caloric intake. Now, by no means do we recommend this approach to losing weight, but it does prove the point that calories do in fact matter for weight loss.

Food choices help us control calories

When it comes to weight loss, it’s not calories OR food choices, it’s both. We should focus on eating an overall healthy diet because the foods that we choose to eat can influence how much we eat, which subsequently influences how many calories we consume.

A study published in Cell^[2] compared the effects of consuming a diet mainly composed of ultra-processed foods to a diet composed of mainly unprocessed foods. The participants were instructed to consume food ad-libitum, which means they ate as much as they wanted. The meals that were given to the participants were matched for the calories presented, energy density, macronutrients, sugar, sodium, and fiber and the participants included in the study were weight-stable adults.

At the end of the study, energy intake was significantly greater in the ultra-processed diet group compared to the unprocessed diet group, with the excess of calories mainly coming from an increase in carbohydrate and fat consumption, and not protein. Participants in the ultra-processed diet group gained about 2 pounds on average and those in the unprocessed diet group lost about 2 pounds on average.

As this study demonstrates, food choices do matter very much for weight loss. However, this is because food choices influence how many calories you consume and not because specific foods inherently cause weight gain or weight loss.

Food Choices and Satiety

This image below shows the satiety index of commonly consumed foods. We can see that highly processed foods like chips, cookies and chocolate bars are all the way on the left and have the lowest satiety scores, whereas foods like steak, fish, and fruit are all the way on the right and have much higher satiety scores. This means that on a per calorie basis, the foods with a higher satiety index will help keep you fuller for longer.

Again, you can technically lose weight by eating processed foods like chips and ice cream, but you might have a very hard time adhering to your calorie targets because these types of foods are not very satiety-promoting. In other words, they don’t do much to keep you full, and if you’re hungry all the time, you’re going to cheat on your diet and likely overconsume calories.

The goal for anyone attempting weight loss is to make it feel as easy and as seamless as possible, which can be accomplished by consuming foods that are going to help you feel full and satiated.

Here are some general dietary rules that will help promote satiety and reduce hunger:

Follow a high protein diet since protein is the most satiating macronutrient and has the highest thermic effect of food.
Consume mainly whole, unprocessed foods, because they tend to be less calorically dense than processed foods and help keep you full.
Reduce the number of liquid calories you consume from things like juice, smoothies, and alcohol, since liquid calories don’t do much to improve satiety. Instead, just eat the whole fruit rather than having the juice and if you’re in the mood for something sweet to drink, chose a zero calorie alternative like a diet drink.

Of course, there are other benefits of consuming an overall healthy diet filled with whole unprocessed foods besides aiding in weight loss. Whole foods contain more nutrients like fiber, vitamins, and minerals, compared to highly processed foods. That being said, there’s nothing inherently unhealthy about processed foods besides the fact that they’re really delicious and easy to overconsume.

A brownie isn’t inherently fattening because it’s a brownie. It's just calorie-dense and easy to overeat. But that doesn't mean you can't include brownies in an overall healthy diet.

Conclusion

No matter how much people want to hate on things like sugar, saturated fat, or even artificial sweeteners, none of these things cause weight gain outside of the context of your caloric intake. Again, the total amount of calories you consume relative to the amount of calories your body expends is the main determinant of whether you gain or lose weight. Some foods, like brownies or cookies, make it easier to eat more calories compared to something like kale, but that doesn’t disprove that calories matter.

It simply shows that the foods you eat can influence your caloric intake if you’re not diligently tracking your calories, which is why consuming a bunch of processed foods can indeed lead to weight gain. It’s also the same reason why individuals who have overall healthy dietary behaviors tend to have a lower BMI and a healthier body composition. If you’re trying to lose weight and you’re thinking about whether you should focus on your calories or your food choices, make sure to focus on both. Eating a well-balanced healthy diet will just make it easier for you to reduce your caloric intake, lose weight, and improve your health.