In a nutshell, the body has a host of involuntary mechanisms that control energy regulation; your desire for output, how much gets burned for energy, how much gets stored as fat, and so on.
Forcibly trying to override those systems with willpower to create a conscious calorie deficit literally causes appetite to increase, metabolic rate to decrease, desire for physical activity and calorie burn during exercise to decrease, and fat storage efficiency to increase.
That's why it doesn't work and is actually a contributing factor to weight gain. I mean, would you take a pill with those side effects if you were trying to lose weight?
There are way too many TV shows perpetuating the eat-nothing-and-workout-till-ya-dropout myth. With people eating rice cakes full of saturated fat that's propelling them towards chronic disease!
Like anything in life we need to be properly educated before we can take effective action. You wouldn't take a car out on the highway until you were 100% sure you could do it with an instructor.
The same goes for our weight, if you have to rely on an instructor, excessive exercise, calorie reduction, sliming club, or diet plan...then you will forever be a student.
The only way to graduate and be fully in control is to learn how your body functions, and know the key nutrients your body requires. That's why it's vital to take a blood sample so that we have a current picture of your vitamin and mineral status, and can identify the root cause of any imbalances that are affecting our ability to maintain a healthy weight.
We know first-hand that unless we invest in self-care and learn about our own health needs, the road to weight loss is never ending.
The first place to start is to acknowledge that what we are currently doing is not working, rather than thinking I am not trying hard enough.
A big part of you knows that there must be another away otherwise you wouldn't keep on trying.
So if you've tried it all, consider that perhaps the solution you are looking for doesn't lie in a gym or local swimming club.
Here are some great books that provide real education and provide a good place to start: