Water is essential.
Why are we constantly talking about water and its consumption? Because we are made up of over 80% water. Water is essential to support the biggest molecules and to produce chemical reactions in our body. We need water at all times and this is why we need a well distributed intake of water during the day.

Gaining weight can be difficult.
It is more difficult for a thin person to put on weight than for an overweight person to loose it. The key is to eat more and more often, and combine it with physical exercise, such as walking, a gymnastics table, swimming and climbing up and down stairs. You should increase the amount of sport you do daily and make it progressively harder.

You should also use your fridge in winter.
A refrigerating system becomes essential if you want your food to be kept in good condition, preserving all its organoleptic properties (taste, smell, etc). It avoids contamination too, because it maintains constant temperatures (without excessive warming up or cooling down) and is more appropriate than parlours, terraces, and exposure to heating systems.