Why Am I Gaining Weight In A Calorie Deficit?

One of the most frustrating moments is when you diet and count every bite, yet the scale doesn’t change (or worse, it goes up).

Today I will roll up my sleeves and help you understand why are you gaining weight, despite being in a calorie deficit (and most importantly) what can you do to start seeing results.

As a whole, people are gaining weight in a calorie deficit because they overeat, without even realizing it. The accumulation of stressful and unexpected situation can trigger mindless eating behaviors and lead to weight gain, despite calorie restrictions on most days.

This means, you may be in a calorie deficit for several days, but all it takes is one day of excess eating or drinking to gain the weight back. Also, you may rely on calorie trackers that provide inaccurate data.

Why Is My Calorie Deficit Not Working?

There are two reasons why your calorie deficit is not working. The first reason is that you may have mindless eating episodes that are triggered by certain moments or uncomfortable situations. The second reason is that your calorie estimates in foods can be widely inaccurate.

Let me quickly expand on those two reasons.

The mindless eating can be caused simply by some emotional situation that happened recently.

We all experience emotions, positive and negative. But we all have different ways of regulating those emotions. Some people relax or distress by drinking, others by taking a hike, and others by eating (source).

So if someone is repeatedly experiencing stressful moments, and they got used to eating as a way to de-stress, it is very likely that not only they will eat more than usual, but they will also hardly remember that eating episode.

Every day we are making over 200 food-related decisions (source).

And during stressful and emotional situations, some of those decisions are being made mindlessly and impulsively “under the radar”.

And because we’ve been distracted, interrupted, stressed, or in the middle of doing five other things, we forget that those episodes even happened.

It’s like grabbing a bag of pastries on the go between the meetings, while driving a car, trying to find a parking spot, and being on the phone at the same time.

The moment you get to your next meeting, the memory of that pastry bag has gone.

A fascinating study was done by Market Research Corporation of America (MRCA).

They assessed over 5,752 people and compared their perceived versus actual food consumption with a conclusion that people’s perceptions of their eating are very different from their actual consumption (source).

See below.

As you can see, the perception of people eating fruits, vegetables, and meat is much higher, compared to reality. On the other hand, the perception of eating sweets is much lower, compared to reality.

Related article: Why Am I Gaining Weight On OMAD?

Not Losing Weight Despite Calorie Deficit And Exercise

The second reason why you may be not losing weight despite calorie deficit and exercise is that fitness apps and the numbers they provide are often wrong. They don’t take into consideration food digestion, absorption, and synergistic effects of nutrients.

This means different foods will have different rates of processing, and therefore, calories breakdown. Here’s how it works.

The body burns calories in three different ways. It’s called energy expenditure aka the number of calories used within 24 hours. Basal metabolic rate (BMR), active metabolic rate (AMR), and thermogenic effect of food (TEF) (source).

BMR is basically all the body processes and energy that need to be required for the basic function at rest (breathing, blood flow, cognitive work, etc).

AMR is the all energy required for daily physical activities. That’s your exercise part and any movement during the day.

TEF is basically the cost of ingestions of food. Energetic cost of food digestion, breakdown, enzyme synthesis, peristaltic mobility, absorptions, urea synthesis, etc. TEF is responsible for around 10-15% of your calories burned during the day.

Macronutrient difference

Studies done on TEF shows that different food has a different effect on calorie burn, depending on the macronutrient content of the food and food type (processed or whole food).

For instance, protein metabolism is the most energy-demanding (source).

Therefore, eating 500 calories of the chicken will increase TEF versus eating 500 calories from bananas. Calories are the same.

But the effect is that 500 calories from chicken are more “metabolically expensive” so you will need to burn extra calories simply to break down, digest, and absorb them.

Whole food vs processed food

Another example is whole foods vs processed foods. In this study, researchers compared eating a sandwich made from whole-grain bread and cheddar cheese, versus white bread with a cheese product (source).

Both sandwiches were measured to be equal with calories (600 calories each serving).

The results showed TEF processes approximately twice as much higher for the whole grain meal comparing to the processed meal.

So despite having the same calories, the body needed to use more calories to breakdown, digest, and absorb the whole grain sandwich.

Related article: Why Counting Calories Is Pointless?

Because processed food sandwich has less fiber, less nutrient density, and more simple carbohydrates, it is  structurally and chemically easier to digest.

That’s why when you simply look at the estimated numbers on calorie trackers, despite being in a caloric deficit, more often than not those number doesn’t reflect the reality.

Related article: 7 Steps On How To Stop Counting Calories

Why Can’t I Lose Weight In A Calorie Deficit?

You can’t lose weight in a caloric deficit because you either miscalculated your daily calories or you have episodes where you impulsively eat more. Weight loss is the effect of caloric deficit done over time, and if you’re not losing weight it means you’re not in a caloric deficit.

In other words, how do you know that you’re really in a caloric deficit? Did you calculate or did you guessed? Both of those estimates can be misleading.

Calorie information of foods usually is incorrect, even by 10-20%. Guessing can be inaccurate also.

There are several ways to really get down to the core reason why you’re not losing weight. And it’s usually because you’re not in a caloric deficit.

Remember that this is the process that involves weeks, to just one single day. And sometimes all it takes is one cheat day or an impulsive eating episode to get the body back into a calorie surplus.

So even if you’re in a 500 calorie deficit for 6 days, and have one cheat day with 3000 calories in total, it is enough not only to stop weight loss but even to gain the weight back.

This is a law of thermodynamics. It’s not possible to be in a caloric deficit and not lose weight.

Related article: Can You Lose Weight Without Being In A Calorie Deficit?

I Am On A Calorie Deficit But Not Losing Weight

If you’re on a caloric deficit but you’re not losing weight it means you’re not in a caloric deficit every day. All it takes is just one day of overfeeding or drinking, where you load up with calories. So despite being in a caloric deficit for most days, one day in a week can stop the progress.

There is not other way around it.

There is a difference between perception and reality. And sometimes our perception misleads us into believing that we’re doing something right. But the evidence (weight, inches) shows differently.

So we can’t be delusional about it. If you’re doing something and is not working, you need to find out why it’s not working. In other words, you need to focus on self-awareness.

The easiest trick to start being master in self-awareness and cut all the BS is by journaling everything that you eat. Not counting calories, but just journaling (source). The simple act of writing stuff down (pen and paper) increases self-awareness and leads to massive change.

But you need to be consistent about it and write down every bit that you eat. People can notice slight resistance while journaling their food. They may feel like:

“Eh, I know what I eat, I don’t need to write this down”

They may “forget” to record anything that seems to be less-than-perfect. But once they commit to really focusing on this small habit, soon they can realize it is a life-changing practice.

Related article: Why Am I Not Hungry On OMAD?

I’m eating 1500 calories a day and not losing weight

If you’re eating 1500 calories a day and not losing weight, then you are either underestimating your daily calorie intake, or 1500 calories is not enough to put you in a caloric deficit. For some people 1500 calories per day is enough to lose weight, but not for everyone.

Restricting calories and gaining weight means you are still in a caloric surplus. Calorie restriction only guarantees weight loss as long as you’re in a caloric deficit. A caloric deficit means your body is getting fewer calories than it needs, so it must utilize stored body fat to compensate.


The only way to lose weight is by a caloric deficit, and if you’re not losing weight is simply means you’re not in a caloric deficit. People’s perception versus reality is totally different, and because we are living in times with the attention span of a goldfish, it is super easy to impulsively eat food, without even realizing it.

That’s why one of the best practices is to exercise your own self-awareness and mindful eating. You can start by using a food journal to document everything that you eat, without being judgemental about it.

Michal Sieroslawski

Michal is an exercise physiologist (MSc) and a veteran endurance athlete. He loves to experiment and share his successes and failures to help busy men and women who want to lose weight.

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