Hello sir/mam my question is that is roughage a nutrient ? I also did not undestand that why to take only 7-8 glasses of water can we take more ? how obesity takes place ?

• The major nutrients of food are carbohydrates, fats, proteins, minerals, vitamins and water. Although roughage has no nutritional value, it plays an important role in our diet. It prevents constipation and helps in regulating digestion. It helps in regular bowel movements. It helps the body to get rid of undigested food.
• It is advisable to drink about 7-8 glasses (2-2.5 litres) of water per day. Drinking excess of water can prove harmful to the body.  If we drink a lot of water in very short intervals of time, our kidneys cannot remove the excess fluid from our bodies. As a result, our blood becomes more diluted than it should be, with very low concentrations of salt. 
• Prolonged consumption of junk foods and fast foods such as fried snacks, aerated drinks, gum, sugar candy, pizzas, burgers, etc. can deprive the body of a balanced diet which may lead to problems such as obesity. Obesity is a condition where excess fat accumulates in the body.