It's important for people to eat as much as they need to give them energy.If they eat too little food or the wrong food they won't have enough money. If they eat too much, they will need to make more exercise;otherwise they will put on weight. 
   Fat is very high in calories, and has been linked with disease. Many experts believe that eating many fat would help to reduce heart disease. Sugar isn't good for energy balance. There's no doubt that too much sugar makes you fat and it is not good for your teeth either.
   On the other hand, fibre that is found in cereals, fruits and vegetables is an important part of a healthy balanced diet. One of the simplest ways of eating much fibre is to eat more bread. It's a good,cheap source of fibre and nutrients without too much  calories.Potatoes are good, too.
   So to keep healthy, eat less fatty food, sweets, chocolate, cakes, jam and eat more bread,potatoes, pasta, fresh fruit and vegetables.

much: a large amount or to a large degree

little: small in size or amount
much
many: used mainly in negative sentences and questions and with "too", "so", and "as" to mean "a large number of"

many
much
more: a larger or extra number or amount.
much 
less: a smaller amount (of), or to a smaller degree.
more