There is also some proof that the type of bacteria that live in your gut can affect your weight. Studies have been done in identicle twins who have exactly the same genetic make up and eat very similar diets however one is overweight and the other is lean. Scientists have found that they had a different types of bacteria in their guts and they were able to pin point a few species that were found only in lean people’s guts and a few that were only found in overweight people’s guts.
Some people are fat because their food intake is higher than the amount of food their body really needs. The body burns food to keep your organs working (heart/lungs/liver etc..) at a certain rate – call it the metabolic rate. In women, this rate is lower than in men. You can increase your metabolic rate by exercising.
Now, if we eat lots of sweets, pastries, fries, etc… o will be taking in lots of high energy food (calories if we measure the energy content of the food) but our body will not need all of it to supply our organs and therefore stock it in certain parts of your body – our tummy is likely to be the place it will store it most (and other parts too). Hence, it is important to eat the right foods in the right amounts – typically called a balanced diet. People who eat a balanced diet and exercise can manage their weight better than those that ignore their body and just eat what they ‘feel’ like eating.
On a general note, obesity is a big issue in the UK because many people don’t understand the concept of a balanced diet and don’t cook much anymore – very few restaurants (and surely not the fast food ones) ensure the meal they serve you is balanced.