It would be concerning if I have gained 4 kg (8lb) in the past 2 weeks This is with the same eating pattern prior. I just don't go to the toilet as regular but there is no reason as to why I don't go?

Gaining 4 kg (8 lb) in two weeks can be concerning, especially if your eating habits haven't changed. This rapid weight gain could be due to water retention or gastrointestinal issues, such as constipation, since you've mentioned irregular bowel movements. It's important to monitor your symptoms and consider adjusting your diet to include more fiber and hydration. If the weight gain persists or you have other symptoms, consulting a healthcare professional would be advisable.