It sounds so simple, if we eat fewer calories and/or exercise more, we can lose weight.  Whilst broadly that may be true, the simplest things are often more complex than they first appear.  If it were that simple, why aren't we all the weight we want to be? 

The problem with slimming diets is that all you seem to think about is food!  Also, if diets alone work, why do they keep inventing new ones? 

For successful weight management, issues such as motivation, and the need for advice to do it healthily, plus encouragement, are extremely important.  We also need to understand how our various life-issues and experiences can play a large part in the way we are and feel.

You may have found that 'faddy' short-term diets don't work long-term for you, and they can be unhealthy too!  Of course you might lose weight for a while, sometimes quite quickly, but then when you stop the diet you put it back on again, which is demoralising and pointless. 

You may have joined a gym with all good intentions, only to find that you go less and less frequently (if at all), so the only thing you lose is the membership fee that regularly goes from your account each month!

Healthy weight loss is about making changes - long-term.  It's about realizing and accepting that what you've been doing before has kept your weight at too high a level.  Unhealthy lifestyle habits need to change, not just the food eaten, and not just short-term.