What is considered rapid weight gain?

I was looking this up because my cousin gained 3 kg in just five days. Apparently, gaining more than 2-3 pounds (around 1 to 1.5 kg) in a day or over 5 pounds in a week is called rapid weight gain, often due to fluid buildup.

In our forum, we usually define rapid weight gain as gaining 2 kg or more in a week without any major change in your diet. This is often not fat, but water retention, and should be checked by a doctor, especially if you have swelling in your ankles.

Gaining significant weight over a very short period, like 1.5 kg in a week, is rapid. It is physically impossible to gain that much actual fat so quickly on a normal vegetarian diet, so it is highly likely to be water weight or hormonal changes. Do check with a doctor.

Ek-do din me agar ek-do kilo badh jaye toh use rapid weight gain bolte hain, ho na. Achanak se itna weight badhna normal nahi hota. It is better to get your thyroid or kidney functions checked once just to be sure.

I experienced rapid weight gain of 4 kg in two weeks when my thyroid went completely out of control. Once my doctor adjusted my medication and I monitored my salt intake, the extra fluid weight went away gradually.