i am 31 year old my weight is 41 i am not gaining...

Underweight causes

• Eating disorders: This includes anorexia nervosa, a serious mental disorder
• Overactive thyroid (hyperthyroidism) can boost metabolism
• Celiac disease: The most severe form of gluten intolerance
• Diabetes
• Genetics
• Infections

Smoothies to gain weight

• Chocolate banana nut shake: Combine 1 banana, 1 scoop of chocolate whey protein and 1 tablespoon (15 ml) of peanut or another nut butter.
• Vanilla berry shake: Combine 1 cup (237 ml) of fresh or frozen mixed berries, ice, 1 cup (237 ml) of high-protein natural yogurt and 1 scoop of vanilla whey protein.
• Chocolate hazelnut shake: Combine 15 ounces (444 ml) of chocolate milk with 1 scoop of chocolate whey protein, 1 tablespoon (15 ml) of hazelnut butter and 1 avocado.
• Caramel apple shake: Combine 1 sliced apple, 1 cup (237 ml) of natural yogurt, 1 scoop of caramel- or vanilla-flavored whey protein and 1 tablespoon (15 ml) of sugar-free caramel sauce or flavoring.
• Vanilla blueberry shake: Combine 1 cup (237 ml) of fresh or frozen blueberries, 1 scoop of vanilla whey protein, 1 cup (237 ml) of vanilla yogurt and sweetener if needed.
• Super green shake: Combine 1 cup (237 ml) of spinach, 1 avocado, 1 banana, 1 cup (237