You might be experiencing “whoosh” effect. Water. I’ve had it always during dieting that my weight was dropping slowly over 3–4 weeks and all of a sudden dropping rapidly (1.5–2kg !) in 1–2 days (and not returning to prior levels).
I assume you have your diet set properly, kcal below required level etc.
When you lose weight, you don’t lose fat cells. You burn fat that is existing in fat cells and they shrink. What happens is also that while you burn fat inside, cells are filled back with water so your weight doesn’t really change much – until water is disposed from body.
There’s a lot of initial weight loss from depleting your glycogen stores. You’re muscles probably look and feel “flat”. The food choices on keto diets tend to be extremely high in sodium leading to water retention. Some people actually recommend the extra sodium to combat low blood pressure.
Constipation is from the lack of bulk and fiber in your diet. Protein and fat are almost fully digested in the sense that they don’t produce much waste. I used to go every 3-4 days when doing keto. More bulk vegetables helps, but without all the breads and pastas you’re not gonna go that often.
It’s really hard to track your progress using the scale because your water retention and glycogen levels will be all over the place causing your weight to fluctuate.
I’m big on tracking calories. It guarantees you’re setup for results. If you’re relatively lean, try bodyweight x 12 to get total calories. Your diet should be 70% fat and 30% protein. Too much protein and you risk your liver converting it to glucose and keeping you out of ketosis. It should work out to about the same amount of protein and fat per day. Your carbs at 20 is fine.
I think you are too impatient the body needs time to get it metabolism switched around to ketosis. Go to the pharmacy and buy yourself some Keto sticks, those will truly tell you if you are in ketosis yet or not. Those sticks will help you in the beginning to fine tune your diet so that you stay in moderate ketosis all the time. It will tell you what you can eat and what not and after a few months you won’t need them anymore.
Don’t ever forget to do some moderate exercise which would help the whole process of switching from carbohydrate diet to ketogenic diet.
Trying adding some fiber to your diet to get things moving. Also it is impossible to tell why your weight loss has stalled without seeing your menu. You could be ingesting more carbs then you think which in turn would knock you out of ketosis/fat burning. Evaluate your diet carefully to make sure you haven’t added any sugars/carbs inadvertently. Good Luck !
Your calories might still be too high but it’s too early to tell.
Track your calories for a month or two. If you’re not losing weight then cut your average daily intake by 500 per day and stick to it for a couple months.
If that doesn’t work then you probably didn’t really do it. Try again but this time count your calories honestly and correctly.
Constipation can be a pretty big deal. Contact a doctor!
A friend of mine struggles with this, her solution is to drink more water, more magnesium, and some powdery stuff that comes in packets called “calm”.