Supplements make certain that you gain weight quickly. Weight Gain is as difficult as losing it. Following are some tips to gain weight: Consume more calories than you burn. Eat healthy food frequently- 3 larger meals and 3 smaller meals alternately. Exercise regularly for healthy weight gain. It keeps the metabolism high. If you eat and sleep well, exercise carefully and use best muscle building supplements, you can expect to gain about 10-15lbs in 6-8 weeks.