UK GCSE level age ~14-16, ~US grades 9-10 Biology revision notes re-edit 14/05/2023 [SEARCH]

Diet and exercise : 2. What are the consequences of an unbalanced unhealthy inadequate diet?

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(2) What are the consequences of an unbalanced unhealthy inadequate diet?

  • Overeating of energy rich foods leads to obesity and ensuing health problems (see section on obesity)

  • Receiving insufficient food can cause starvation or malnutrition.

  • A person is malnourished if their diet is not balanced.

  • Lack of a good healthy diet can cause a person to be overweight or underweight.

  • An unbalanced diet may also lead to deficiency diseases or conditions such as Type 2 diabetes.

  • You need to eat the right types of healthy food and in the right amounts/proportions to maintain a healthy body.

  • Starvation is when people do not get enough food to eat.

    • The effects of starvation include slow growth (particularly of young children) and a greatly increased risk of infections and irregular periods in women.

  • Malnutrition: People who live on a poorly balanced diet are malnourished and malnourishment is common in the poorer developing countries of the world e.g. in Africa. What you then get are deficiency diseases.

    • Don't confuse malnutrition with starvation, where there is not enough food of any description to maintain life - the pictures you see on your TV of very thin people in Africa, on the edge of life exemplifies this pitiful state.

    • However, malnourished people can be overweight as well as thin, from an imbalanced diet e.g. those fat people who live off too much junk food and excess fat are as malnourished in some ways just as much as a 'thin' person in a poor third world country!

    • The effects of malnutrition do depend on what is missing from the diet but common symptoms are slow growth in children (arrested development), weight loss in adults, poor resistance to disease and infection, fatigue (low physical activity, lack of energy).

    • Particular deficiency diseases are caused by lack of specific vitamins or minerals e.g. lack of vitamin C causes scurvy which leads to problems with gums, skin and joints. Organ and other tissue is not efficiently repaired and ulceration is common.

    • Lack of iron can lead to anaemia, lack of oxygenated haemoglobin in the blood - you become weak and lacking in energy as respiration is less efficient.

    • Not getting enough protein in your diet causes kwashiorkor, an illness caused by severe protein deficiency, often seen in people of developing countries e.g. in Africa.

    • Lack of calcium in a diet affects bones, which become soft and poorly developed in young children. Calcium based minerals are an important component in the structure of the teeth and skeleton.



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