What is obesity - physiology

Published on January 31, 2016   16 min

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Other Talks in the Series: Obesity: Science, Medicine and Society

So, after Andrew telling us about how we can measure and define obesity, let's have a little look at the physiology behind it. How did we get obese in the first place? First thing to recognize that obesity is a chronic condition.
But it's not just one single disease. Every obese person is different and there are many types of obesity. People differ in the distribution of their fat. For example, you may hear people described as apples or pears, pears having greater weight around the bottom and thighs and apples having greater weight around the trunk and mid-section. And it's the apple shape that's particularly associated with poor health and with metabolic complications like diabetes. That's because the apple shape usually indicates that there is fat inside the body, not just in a layer under the skin but right inside the abdomen and inside the organs. And you'll be hearing a lecture from Professor Jimmy Bell about measuring and estimating exactly where the fat is within the body and the implications of that for health. The other thing to think about is when obesity starts. There are some people who are obese from early childhood, even babyhood. And they tend to remain obese throughout their lives. But many of us don't become obese until the teenage years, after childbirth or later in life. And then there's a third set of people with obesity
that have obesity secondary to another condition, for example, a thyroid disease or Cushing's syndrome. I'm a geneticist and I'm really interested in the interplay of genes and the environment in causing obesity. We need to think about the different causes of obesity in different people. There are some people who may have mostly environmental causes of their obesity. They maybe don't know about nutrition, maybe they live in a poor food environment. They have a lot of deprivation and they don't know how to control their environmental stimuli. They may have relatively small contribution of genes to their condition. However, there are other types of obesity, that we will be hearing about later in the course, that are caused by genes, almost entirely. So we have single gene recessive and dominant forms of obesity