When weight loss is your number one goal it can be easy to become preoccupied with calories, exercise and the foods you will and won't be eating. It can take up plenty of time, energy and focus and one of the biggest issues with this is that when the focus stops, so too does the calorie control.
This is one of the most common reasons weight is regained after losing it. For this reason, adopting more general dietary rules and limits tends to work better for weight control long term. Weight loss may be slower, but it is more sustainable.
You haven't dealt with your issues
There are many emotional and psychological reasons people eat too much — loneliness, habit, unhappy relationships just to name a few and the reality is until you take control and sort these issues out eventually you will revert to bad habits and regain any weight you have lost.
So if you know that emotional eating is at the root of your overeating, see a professional and sort through your issues for good.
Your diet does not factor in socialising
Enjoying indulgent food with friends and family is one of life's most simple pleasures which means any diet that does not factor this in to some extent is unlikely to be successful long term.
To achieve weight loss, your diet does not have to be perfect, rather consistent which means that an occasional few glasses of wine, or a slice of birthday cake is not an issue and should be a part of your regular, healthy food regimen.
You are hungry
Excessive hunger throughout the day is a sign that your baseline diet is lacking calories, carbohydrates or proteins and restrictive diets that cut these nutrients to too great an extent will make it very difficult to not be thinking about food.
Hunger every 3-4 hours is normal, but constantly craving sweet foods is your body's way of telling you that you need to eat a little more.
You have not factored in exercise
While calorie restriction will result is weight loss, one of the only ways to boost metabolic rate and actually become better at burning calories so you can eat more food long term is to build muscle mass.
This means if your goal is to not only lose weight but keep it off you need to get into the gym a few times each week and build some more muscle tissue.
You have no plan for how to continue
In general people are either "on" a diet or "off" it which means even though they may have been successful in losing a few kilos, once they go off their diet and return to their old eating habits most if not all the weight they have lost is generally regained.
The key to losing weight and keeping it off is to have a transition plan that allows you to return to regular eating in a way that does not undo all the hard work you have already done. A dietitian will be able to help you with this.