Lifestyle & Disease - Diet and Exercise (GCSE Biology)

Lifestyle and Disease: Diet and Exercise

Diet

Balanced Diet

A balanced diet is one where you intake food from different food groups in the correct proportions to get different different essential nutrients.

The different food groups/ nutrients and their sources can be seen below:

Factors Affecting Dietary Needs

• Age – children and teenagers require more energy as they are still growing and tend to be more active than adults.
• Gender – men are larger with more muscle so require more energy.
• Physical activity – those are physically active require more energy.
• Pregnancy and breastfeeding – they need more energy for both themselves and their growing and developing baby

Diet and Health

Malnutrition is basically having a poor diet. This could be either nutrients in excess e.g. in obesity or not getting enough nutrients leading to starvation.

Poor diet can lead to health problems:

• Obesity. Excessive eating can lead to excessive body fat which can lead to other health issues like high blood pressure.
• A poor diet can lead to cardiovascular disease. This is because the increased risk of obesity can increase the risk of cardiovascular disease, as eating too much saturated fat can increase cholesterol levels that can deposit on the inside of arteries, causing them to eventually become blocked which can lead to coronary heart disease.
• Obesity has a causal relationship with Type 2 Diabetes. Obesity makes the body less sensitive to insulin, so can lead to an increased incidence of Type 2 Diabetes. Therefore the best way to avoid diabetes is to limit the number of high-sugar foods you eat.
• Starvation. This is when you aren’t eating enough nutrients so the body is unable to function properly. This can lead to tiredness and weakened immune system.
• Constipation. When you don’t eat enough fibre or drink plentiful of fluids then it can prevent the passage of faeces through the rectum. This can cause discomfort and if left untreated, it can lead to damage and severe pain.
• Scurvy. This is due to Vitamin C deficiency and can cause poor wound healing, pain and bleeding gums.
• Vitamin D deficiency. This can be due to decreased Vitamin D intake or lack of exposure to sunlight. As Vitamin D aids calcium absorption, the lack of Vitamin D can cause bone weakness and pain as well as
  fatigue and dental issues.
• Iron deficiency. Not eating enough foods with iron can cause iron deficiency. As iron helps build haemoglobin which carries oxygen, iron deficiency can lead to fatigue and shortness of breath due to the lack
  of oxygen.
• Protein-energy malnutrition e.g. kwashiorkor and marasmus. Kwashiorkor is when you have protein deficiency. This leads to water potential imbalance in the body and water moves via osmosis causing
  swelling. Marasmus is severe malnutrition similar to starvation which can lead to being very thin with extreme fatigue.

Measuring Obesity

Body Mass Index (BMI)

You can calculate BMI as a guide to identify if someone is of the correct body weight taking into account of their height by doing:

However, BMI isn’t always reliable as your high mass might be due to high muscle content which isn’t unhealthy. So a high BMI index may not always mean you are unhealthy.

Waist to Hip Ratio

A more reliable measurement is waist to hip ratio:

Having a higher ratio means you’re carrying more mass around the middle of your body which is abdominal obesity. This is what increases your risk of type 2 diabetes and other obesity related problems.

Exercise

The Effects of Exercise on Cardiovascular Health

• Exercise can reduce the risk of cardiovascular disease, as it increases the blood supply to the heart and reduces cholesterol levels.