How can lifestyle, genes and environment affect health?Body Mass Index (BMI) and health

Our genomes interact with our environment to create our phenotypes. While some aspects of our environment are beyond our control, scientists are realising that lifestyle interacts with the genome too.

Part ofBiology (Single Science)Keeping healthy

Body Mass Index (BMI) and health

A risk factor for many diseases - including cardiovascular disease, fatty liver disease, and diabetes - is weight. The is calculated using a person's mass and their height. Your BMI is an indication of whether your body mass is at a healthy level in proportion to your height. A very high BMI means that someone is overweight or even obese.

There are different charts for adults and young people. The BMI which has been calculated is compared to the appropriate chart in order to discover whether the person is underweight, a healthy weight, overweight or obese.

Question

A 16 year old boy has a body mass of 65 kg and is 1.70 m tall. Calculate his BMI.

BMI and disease

People with a very high body mass index (BMI) are defined as obese.

leads to high and the build-up of fatty deposits in the arteries, which lead to . It also increases the likelihood of developing , another risk factor for cardiovascular disease.

Being obese - with deposits of in the abdomen - increases blood pressure beyond normal levels and increases levels of blood lipids.

Type 2 diabetes

Body fat also affects the body's ability to use .

Type 2 diabetes is where the body's cells lose their sensitivity to insulin - they no longer respond, or respond less effectively, to the insulin that's produced. This causes glucose levels in the blood to rise to dangerous levels.

Overweight people are three times more likely to develop Type 2 diabetes. People who are obese are seven times more likely. The bar charts show the increased risk of developing Type 2 diabetes associated with people's body mass index (BMI).

The bar charts show the increased risk of developing Type 2 diabetes associated with people’s Body Mass Index.

There is evidence that changing to a healthy diet can cause Type 2 diabetes to go into . The risk of developing cardiovascular disease and Type 2 diabetes can be reduced by eating a balanced diet, with unrefined, unprocessed, 'whole foods', and taking regular exercise.