The average person can probably build around 0.5lbs (around 0.25kg) of muscle tissue per week at the most, on average. Some weeks might be a little bit higher some lower, but it is fairly accurate. Doesn't look like much? Well if you maintain that for the whole year you will add 26lbs (11kg) of lean muscle mass. Which is something that you VERY rarely see in non-beginners people not using drugs.
Sure some can gain more weight but it will be a mix of muscle, fat, increased glycogen and water storage. Trust me, from experience 26lbs (11kg), or even 15lbs (6kg) of MUSCLE makes you look like a totally different person.
When you understand and accept that you will see that your question is fairly easy to answer.
Daily weight fluctuation (water retention level, stomach content, un-excreted waste, etc.) in a average person can be 4-6lbs/2-3kg (more in some cases).
So on any given day you might be 4-6 lbs/2-3kg heavier or lighter.
And you can, at best, gain 0.5lbs/0.25kg of muscle in a week.
What I'm saying is that it's quite possible that you ARE gaining muscle yet your weight seems lower (because the other factors can be down).
You could NOT be gaining muscle but adding fat.
The daily fluctuation makes it impossible to evaluate day-to-day if you ate enough or too much.
You need to evaluate every 3 weeks or so to get a good idea.
Register your weight every day and make an average of the whole week, this will give you a more precise idea of your real weight.
If you looked at it day-to-day you would assume that your weight stayed the same and you didn't gain muscle. But if you look at the average you added 0.75kg which is an average of 0.25kg per week which is a normal rate of muscle growth in a non-beginner not using drugs.
Based on a day to day evaluation you would think that you need to add more food. BUT if you look at the real progression you are following a normal curve.
YES BUT CHRISTIAN AT FIRST I GAINED WEIGHT FASTER
Of course if you went from underfed (especially undercarbed) you increased muscle glycogen. Maybe the 250g of carbs were not enough to keep your glycogen stores full (the brain alone requires 100-150g) so when you increased carbs intake you stored more glycogen in the muscles, which also pulls water in, giving you a rapid weight gain. AND makes the muscles look fuller, so you assume the quick gain was from muscle and you now expect the same rate of gain.
The fact is that most people have unrealistic expectations of how much muscle they can build, or how fast they can build it.
YES you can gain more WEIGHT and on some weeks you might gain more than 0.25kg. But not much. Any extra weight gained is either from fat, water retention, added glycogen or stomach content.
And the problem is that when you are not lean (let's say 15-20% body fat or more) if you add a kg of fat you don't "see it"... you don't "look" fatter, you look the same. So it's easy to assume that you only gained muscle. You likely didn't.
A man I respect immensely, Dr.Mike Israetel mentions in his "Renaissance Periodization" book that you should shoot for a 2lbs/1kg gain per week. If you don't reach that you should increase calories.
That might work with people who are fairly lean and muscular; but when someone already has a good amount of fat I don't like to pile on even more. I believe that an average gain of 0.25 - 0.5kg per week is a good target if you tend to put on fat easily. At that level you are mostly only adding muscle and maybe some water retention.
A natural athlete (not using drugs) cannot force the body to build more muscle than it is programmed to do. As long as you are nor deficient in building blocks (protein) and energy (carbs/fat) your body should progress.