Deep down you know the latest diet you've just started isn't going to work. Sure, the first few days you're buzzing with high spirits and dreaming about the new clothes you'll be able to buy, but it soon wears off doesn't it? You don't need me to tell you diets are extremely hard to stick to, but the reason why hasn't been discussed properly.

The reason is choice. Yep, it's that simple.

To elaborate, our appetites haven't evolved to cope with the enormous amount of choice that exists today. Why does this matter? Because choice stimulates appetite. That's why you can alway fit in a chocolate pudding, even though you couldn't manage another mouthful of potatoes. Your mind says "Hey, that's enough potatoes!" and makes you feel uncomfortably full. On seeing dessert it then goes "Ooh, chocolate pudding, that's different!" and makes you hungry again.

Now this wouldn't be so bad by itself, but the problem is made worse by the huge and varied types of food which we are surrounded by. If you compared the foods stocked by a typical supermarket today with one from 50 years ago the difference would be staggering. Add in the new foods from around the world and you end up with a constant hunger that never seems satisfied. Our 'full' signal is simply drowned out by our appetite.

For example, the UK didn't have takeaway pizza chains until the early 80s, which just so happens to be around the time obesity started increasing. Supermarkets became more powerful (UK's Asda is part owned by Walmart) and the range of foods exploded. Brits who were happy with simple meals were suddenly eating like kings every day, leading to expanding waistlines.

In newly emerging economies like India and China obesity is on the rise (along with related conditions such as insulin resistance). More food choice goes hand in hand with weight gain.

So to succeed in losing weight you need to start taking a list of foods to buy at the supermarket. Stick to it rigidly and don't be tempted by special offers (unless they are for fruit and vegetables of course). Remove any tempting food if possible from your home, although this is hard if you have a family.

Also, a fun and interesting way to help lose weight is to eat foods your ancestors used to have. Try and find out the diet your grandparents and great-grandparents used to eat and try to do the same once a day. If they only ate meat once a week or month, try doing the same and see if you feel any better.

Why not make a new years resolution to stop the circle of fad diets and take control of your appetite.

About the author:

Pam Kaur runs the popular website Beautystartup for beauty therapy professionals.