How our genes can cause obesity? Over 100 obesity genes have been identified so far. Some of these can often cause obesity by interfering with metabolism and fat burning capacity of the body.
So, its not a total lie when someone says "its not what I eat, really, its my bad genes!".
The famous Ob-gene is thought to interfere with leptin production - an essential hormone which signals fullness. A mutation in this gene can cause an early onset (childhood) obesity which can carry on to adulthood making the person more likely to suffer from obesity related complications such as heart disease and type 2 diabetes.
The bad news is - we cannot change our genes. The good news is - even if susceptible to "fat" genes, lifestyle changes and the right diet will make one loose weight - guaranteed! Dr. Barnard suggests in his book (Turn off the fat genes, Harmony books, 2001) that certain types of foods can silence these fat genes and and essentially make you lose weigh by naturally burning fat more effectively. Interesting!