My only way to stay normal (which I am and work hard at) is to watch everything I eat, dissociate proteins and carbs always, eat hardly any carbs at all, and exercize.
Soooooo..... all that yada yada yada to say.... the best way to gain weight is:
- not to dissociate proteins and carbs and fruit (have the Spaghetti Bolognese and a banana in the evening, for instance)
- not to respect the body's metabolism chronology. (eating a full dinner at night when your metabolism is slow will help gain weight)
Protein shakes are actually a no-no if you want to gain weight. Protein by itself will help you lose weight and build muscle.