Question: what are the side effects of not eating enough protein?
Answer: Skin, hair and nail problems. Protein deficiency may leave its mark on the skin, hair and nails, all of which are largely made of protein. ... 
Loss of muscle mass. ... 
Increased risk of bone fractures. ... 
Bigger appetite and increased calorie intake. ... 
Risk of infections. ... 
Fatty liver. ... 
May inhibit proper body growth in children.