Most people are haunted by sudden weight gain. However, these are just weight fluctuations. Weight fluctuation is totally normal and is common to everyone. Our weight tends to fluctuate on a daily basis and there is nothing to be too concerned about.
Hey, tough soul. I’m Alyssa.
Still remember after you had a big meal and you found that you are 1 pound heavier? Or do you feel fatter the next day after a family gathering?
I have a piece of good news for you. What you’ve concerned about might not happen at all. In the end, you’ll find that you did not gain any weight in actual. We call this weight fluctuation.
I’m going to introduce what is weight fluctuation to you and in what condition you actually gain fat. You might be surprised that, most of the time you think that you had gained fat, but actually you are not! Keep reading!
Contents
What Is Weight Fluctuation?
In case you did not hear of weight fluctuation (or body fat fluctuation) before, here is what it looks like. You always have a flatter tummy in the morning compared in the evening. Every moment after meals you will feel a little bit ‘fatter’. And also, you will have those days that are ‘leaner’ and those days that are ‘fatter’. You might be concerned that you are gaining fat.
Here’s the truth, these short-term changes in your weight and body composition have nothing to worry about. It happens all the time for everyone. Yes, including those picture-perfect fitness influencers that you look on social media — but they did not tell you.
On average, our weight will fluctuate throughout the time for about 1-2 pounds or 0.5-1kg. Therefore, I could say that, the weight that you had gained in a short time, most of the time is just temporary and will go off soon.
Reasons For Weight Fluctuation
There are different reasons for temporary weight gain. Some of them are quite straight forward, which is the effects after having a meal. While some of them are little known, which is the affect causes by stress, hormonal changes and etc. Here are some of the reason why you suddenly gained weight, that isn’t much related to actual fat gain:
Temporary Weight Gain From Diet
The content of your ‘weight’ actually consists of water, carbs (which will be turned into glucose), and the volume of the food itself. You did not expect the food that you ate just disappear in your stomach, aren’t you? Every food needs time to digest, and before it turns into 💩💩, surely its weight will still remain in the stomach.
Besides that, too much carbs intake in one place will cause water retention, therefore, resulting in weight gain. Each gram of carbohydrates will mostly retent 2-3 grams of water. If you had consumed 100 grams of carbohydrates, then it will accompany 200-300 of water together. Don’t worry, this isn’t fat. It just some extra glucose that is stored in your liver and muscles.
Excess sodium also causes water retention. Most of us notice sudden weight gain after holidays due to too much sodium that is found in those delicious meals. However, the remedy is just simply to reduce sodium intake for the next few days and drink more water. You’ll be good to go.
Other Reasons for Temporary Weight Gain
While the diet factor for temporary weight gain will be more straightforward. There are some reasons for weight gain that might surprise you.
The most significant one is that you might currently be experiencing stressful life or not enough sleep. These reasons might cause weight gain and your stress level that causes cortisol to rise. Cortisol is one of the stress hormones that serve the function of regulating metabolism and increasing blood sugar. It is highly related to our weight. Both stress and lack of sleep will affect your cortisol level more or less. Often time when you did not get enough sleep, your cortisol level also will creep up and end up in temporary weight gain.
Therefore if you suspect your weight gain is caused by these issues. See whether you can remove the stress factor or practice mindfulness, or return to a regular sleep routine. Once your lifestyle started to improve, the gains will vanish together.
How About Body Fat?
Now let’s further into the aspects of body fat. As I said, body fat had no relation with your weight and I do not recommend you interpret your weight as your body fat, here’s why we need to look at body fat from another perspective.
I know that is your most concern. Do you gain fat after you are eating, specifically?
This is the short answer: Yes. It’s true that within 4-8 hours after eating, our energy will immediately store in a form of glucose (for carbs), amino acid (product of protein), and fat .
But I have my long answer too. Which is: Not likely.
Although these ‘storage’ immediately resulted in your waistline just under half a day. But, you’ll likely use them up before they turned into long-term fat.
The energy eventually balanced out itself.
If you had a hard time comprehending how does it possible. Imagine this, the energy storage in our body isn’t working just like a static container, but a pendulum that is constantly shifting from both ends. You will have both fed state, but also fasted state. Eventually, both of these will balance out themselves, so that your actual body fat remains unchanged.

I’ve met someone that skip regular meals because they think they will ‘gain fat’ from the food that they had eaten. No, in fact, they had gained nothing.
But, here’s the critical one.
The scenario above is that you are eating your regular meal, and it’s the same amount of food you consumed all the time. Therefore it will be no change in your current body fat. This means, if your maintenance calories are about 1600kcal, then continue eating the same amount of food will not make you gain anything.
What if you Go Over?
Sometimes, your might not possibly use up all the energy that you had consumed. Those extra energies will be stored for future usage. It will be used during the time when the available energy isn’t enough so that it will reach out from the storage.

So if you eat in surplus, then you will gain weight and vice versa.
Well, you might in horror how. It means that you still gain fat if you overeat right? But wait a minute, not so soon.
Remember, the analogy I describe above is only on a daily basis. This difference is so subtle that if you have a few days in a row that is in surplus, it’s still okay and won’t make much difference. The overall change to your body fat happens on a longer unit, let it be at least a month.
Fat Gain Is Slower Than You Can Imagine
When it comes to fat gain, only the calories of the food count. No matter how much volume the food accumulates and no matter how ‘unhealthy’ the food is (in fact there is no unhealthy food!).
As I mentioned, only those extra calories on top of your TDEE will be stored and further turned into fat.
If you wonder how much food will make you gain fat. Here’s the equation. It takes 3500 kcal to gain one pound of fat. In metric, it’s equivalent to about 7000 kcal of excess calories to produce 1kg of fat.
This is how 7000kcal looks like. You need to be an extremely big eater to reach this amount of food.

Don’t forget that, these extra 7000kcal is not include your regular meals. In other words, if your normal diet is 2000kcal per day, then you need a total of 9000 kcal to gain 1 kg of fat. And you still have your resting metabolism that accumulates up to almost 60% of your daily energy expenditure. Not to mention this basal metabolic rate still does not include the daily activities that required about 30% of your energy.
A real-life example:
Someone had eaten an extra bowl of pasta and the pasta weight 365 grams. That isn’t 100% turns out to be 365 grams of fat, we need to look at the calories of the food itself, also how much your body had used up the calories.
365 grams of pasta is equivalent to about 400++ kcal, then actually you just increase for about 0.1pound of fat. In hard theory, there is still a need to depend on other conditions such as metabolism after you had consumed carbs (our metabolism tends to increase after overeating in carbs).
In the end, maybe only less than 10% of how much you overeat will turn into fat. Yes, you still gained fat, but just a little bit of it.
The true fat gain will be gradual and caused over time. Most of them won’t be noticeable within just a week, or even months.
Final Thought
Most people get freak out when they experience weight gain before knowing the theory of weight fluctuation. However, if you look at the conversion of how much calories actually turn into fat. You’ll realised that fat gain is less possible than you imagined.
It is totally possible to revert these. Therefore you don’t need to beat yourself up and skip your meals the next day. Just pretend nothing happened and don’t make overeating a habit. Remember not to try to ‘undo’ the meals because you’ll likely lead into yo-yo dieting soon.
When you return to your regular routine, you’ll be surprised that most of these will fade off after a few days. Cheers!
Let us grow together,
Lyss.
Leave a Reply