Please House, Is it through that Sugar, Salt and flour shouldn't be too consumed. A friend told me this and i hardly believe him.

This sound like plain scare mongering to me. Whilst it is true that you should reduce you intake of Salt, Sugar and Carbs, it is impossible to totally eradicate them from your diet. What you need to do is reduce your intake of refined sugar(table sugar), refined flour (white), and Salt in general.

your body needs salt to survive, you need to do so in moderation though

sugar has no nutritional value save calories so unless you need it to supplement your caloric intake do so in moderation.

processed flour is very low in nutritional value while whole grain flours (fine ground has little taste difference) is very nutritious. if you cannot find or dont like the taste of whole wheat flour or meal (corn, barley, oats) you can add potatoe water (water left over after boiling potatoes) rather then regular water when using processed flour to make it better for you.