Balance Diet Revision Notes

The Balanced Diet A healthy human diet should provide ; Sufficient energy providing foods to enable the body to carryout internal processes and external activities Sufficient materials for growth and for the repair and replacement of cells and tissues The dietary requirements include ; Carbohydrates Lipids Proteins Mineral ions Vitamins Water Dietary fibre A balanced diet provides adequate quantities of all the nutrients required by the body. Lack of particular nutrient could cause a deficiency disease. The quantity of nutrients needed by an individual varies according to their age, gender, body size and level of physical activities. Carbohydrates 17 kJ/g High energy value Satisfied most of energy requirement (because human diet consist of more carbohydrates the lipids and proteins) Easily digested Particularly useful for quick energy Food sources ; potato, bread, rice pasta, sweets It forms the bulk of a meal, which is good because it is a rich energy source Protein 19 kJ/g Used for growth or repair of all cells Used to strengthen bone and muscle Many functional uses as enzymes, haemoglobin and some hormones Food sources ; all meats, green gram soya, egg, fish Protein malnutrition leads to “KWASHIORKOR” Mental retardation Swollen abdomen Cracked skin Liver damage Fail to produce antibodies against some diseases Usually irreversible 60 % death Lipids 34 kJ/g rich energy source take a long time to digest, because molecules are complex excess saturated fatty acids (mostly in animal fats) converted in to cholesterol plant oils consist of unsaturated fatty acids (use of margarines produce from plant oils are much safer) Roughage refers to dietary fibre which is mainly cellulose fibres in plant tissues food sources ; vegetables, fruits uses : add bulk to the diet increase and stimulates peristalsis

prevents constipation Factors that affect dietary requirement Sex – males need more energy than females So more proteins should be there in diet of males Age – young people need more energy than old people Cell division, growth is very efficient in young poeple Occupation – depend on level of activity Road worker needs more energy than office worker Climate – cold region people need more energy than hot region people Pregnancy / lactation –more protein, carbohydrates, calcium, iron and vitamins required Less protein to fetus causing : reduction of growth, lack enzymes, poor immune system, effect cell division and healing of wounds Dangers of an unbalanced diet Starvation malnutrition is lack or excess of nutrients in diet starvation is caused due to insufficient levels of all nutrients in the diet due to starvation : convert glycogen (in liver) to glucose last 12 hours convert subcutaneous fat (under skin) last 2 days convert cushioning fat (between organs) protein/cells breakdown (first in muscles) total starvation leads to “MARASMUS” Under weight (about 80% weight loss) Thin arms and legs Face appears old looking No brain damage, no liver damage Usually reversible Anaemia Due to a lack of haemoglobin which leads to a lack of red blood cells. Because of that lack of oxygen to the tissues Common causes ; Iron deficiency in diet Excess menstrual bleeding in women Hook worms Symptoms : pale appearance, fatigue, breath less ness, general debility(weakness) Treatment : iron tablets Obesity Cause due to over-eating of fatty food and junk food Excess body weight Fat storage is beyond healthy level Dangers : Heart diseases – over working of the heart may lead to heart faileur Arthrosclerosis – due to excessive cholesterol Due to narrowing of arteries by cholesterol rich plaque Diabetes mellitus Lack of insulin (which is a hormone secreted by pancreas)

Insulin increases the cell permeability to glucose and reduces the blood glucose level to maintain constant level of glucose Symptoms : Hyperglycemia (high blood glucose) Dehydration of cells due to loss of water Metabolism slows down Glucose in urine Weight loss Excessive urination Home work (2004 May) 1) What is meant by the term balance diet and what are the main constituents of a balance diet? (4) ………………………………………………………………………………………….. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. ………………………………………………………………………………………… 2) How might a balance diet for an office worker differ from that of a miner or builder? (4) …………………………………………………………………………………………. ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… ………………………………………………………………………………………… 3)

Why do teenagers require more vitamin D than adults? (3) …………………………………………………………………………………………. ………………………………………………………………………………………… ………………………………………………………………………………………… …………………………………………………………………………………………