Can protein intake cause constipation?and can it increase weight

Yes: Excessive protein intake can lead to constipation. Hence increase fiber, remain active and drink lots of water. Gaining weight may depend on other factors like total caloric intake , basic metabolic rate and level of activity.

Yes: Often, protein foods are lacking in adequate fiber. Consequently, if one does not add enough fiber (e.g., fresh vegetables) and water to the diet constipation will result. Consuming protein is not typically associated with weight gain, except when taken in portions with too many calories. Consumption of carbohydrates (especially processed foods) is associated with weight gain and diseases.

Yes: Some people are allergic or have problems with dairy or whey products as the protein ingredient. Lactose is can definitely be an issue. Try and buy some protein products that are lactose free. Read reviews of products before buying and ask if there is a return policy if digestive issues. Protein can help increase weight if you are lifting properly.