Your body works in exactly the same way as your bank account. If you use more than you put in it gets smaller, if you put in more than you use it gets bigger. That part is quite simple. Having said that, to say that a person is fat because they eat to much is like saying a person is dead because their heart has stopped beating and they have stopped breathing. It may be factually accurate but it doesn't actually explain very much.

So, there are some medical conditions, for example having an underactive thyroid, which might make you more likely to put on weight, but then you need to eat less.

Diets, as we understand them in the Western world, don't work, they can only ever be a temporary fit. This is because if you "go on a diet" then eventually you will come off that diet, possible when you have reached your goal weight. You will then revert to your previous eating habits and you will very quickly revert to your previous weight.

The only thing which does work is making permanent, sustainable, lifestyle changes. Look at the things which are causing you to be fat and change them.

Society does tend to give the impression that being fat is some kind of sin. It's not a sin and you don't have to pay penance to absolve yourself. Losing weight has to be at least as much fun as putting it on was, and it can be. You just need to find something that works for you.

Unfortunately we are biologically and psychologically predisposed to overeat when we have the opportunity and to store that additional energy in the form of fat. It is what has made us successful as a species. When we were competing for food, it's the ones who were most successful who survived and produced offspring. So it's not surprising, now food is in plentiful supply obesity is becoming and increasingly serious problem.

Learn to fight nature what comes naturally:

Ensuring your supply - Have you ever wondered why you feel compelled to eat just because somebody around you is eating? You are ensuring your supply. You body is telling you this is a limited resources therefore you must ensure you have your share. Remind yourself that there's plenty of whatever it is available. So your brother might be eating the last of the chocolate chip cookies, but there are more in the shop. You can buy chocolate chip cookies whenever you want and eat them to your heart's content. Only eat one if you genuinely want one. I would suggest if your brother started eating them it was him that wanted them not you.

More means more- Given a seemingly endless supply of food we will almost always eat more than we actually need. Again we are ensuring our supply. Feast today could mean famine tomorrow. Before you go back for seconds, ask yourself are you really hungry? or just preparing for a famine that won't come?

Variety is the spice of life - We are biologically predisposed to enjoy variety. Being able to eat a variety of things has made us more successful. Be honest, if somebody gives you a box of chocolates, you want to try every flavour don't you? Offered a choice of 16 different types of sandwiches you are going to eat as many different ones as you can. This is probably the hardest one to deal with. This is actually a good thing. Our love of variety is the key to successful weight management. So be selective, only pick the thing you really want the most. Don't think of it as depriving yourself, think of it as treating yourself only to the very best of what life has to offer.

Waste not, want not.
You can hear your mother saying it can't you. Now we are all encouraged to be considerate of the environment wasting food is being frowned on anew. Be sure of this, it is every bit as wasteful to eat something you don't want or need as it is to throw it in the bin. What's more it will annoy you for a lot longer around your waist than in the waste. The key to avoiding waste food is to buy less than you think you will need and put less on your plate than you think you want. You aren't going to starve, seriously, there's no need to panic.

Don't expect instant results. It took you a while to put on the weight, don't expect to lose it overnight. Don't get downhearted if it seems to be taking a while. If you have adopted an eating regime you can live it for life, it doesn't matter how long it takes.

Finally don't forget to love yourself. Weight problems often go hand in hand with self loathing and low self esteem. Your size is only one thing about you. There are lots of great things about you. Focus on them.