Your body weight depends on a lot of things with your lifestyle and genes playing a key role. The best way to maintain a healthy weight is to make sure energy consumed is balanced with energy burnt, this is often referred as the energy balance equation. Our body gets energy from the food we eat and the drinks we drink and this energy is calculated in kcal. An average human above the age of 18 needs 3000 calories a day. So when the body gets excess of this energy, it will store it in the form of fat regardless of the form it was consumed in.
Our body uses the energy we consume for three main things, for normal functioning, for digesting food, and for other physical activities. Normally most of the energy is used for normal functioning (60%-75%) while the remaining 10% and 15%-25% is used for physical activity. Our bodies are burning energy all the time, even when we sleep. So if we want to gain an extra pound of weight we would need 3500 calories, (1 lb=3500 calories) and similarly to lose a pound of weight we would need to burn 3500 calories.
So to answer the question, does sleeping causes weight gain, it is important to have information about the whole routine of a person and not just his sleep cycle. To be clear, sleeping by itself can’t cause weight-gain, weight-gain depends on energy consumed and energy spent and the key to gaining weight is balancing out the energy balance equation properly. You can also improve your lifestyle and take good mass-gainers like Endura Mass.