Whether we know it or not, virtually all diets work on some form of calorie control. It may be by restricting food groups (grains/processed foods), counting points, restricting intake (5:2 diet) or some other means, but they are all forms of calorie restriction. By knowing that calorie control is probably the most important part of a diet, we can use this to free our diet. Also, virtually all food groups offer some form of benefit that you can't get from another, so cutting out entire food groups when you don't have an intolerance isn't a wise choice.
Flexible dieting is an increasingly popular alternative to the more rigid diets that have been popular over the years, the main benefit of which is staying power. Flexible dieting offers you a plan you can follow indefinitely without the guilt or monotony asscocaited with rigid diets.
The Problem with Rigid Diets
The main problem with rigid diets, even if you can see them through, is what do you do once they're over. This is the reason so many people yo-yo diet. They see an over strict diet through for X amount of weeks, lose some weight, then go straight back to their old habits as they're not able to incorporate the diet into their normal life. This has the inevitable result of the weight coming back with a vengeance and possibly adding more than was lost.
The Flexible Diet Alternative
Flexible dieting offers a long term alternative as it allows a wider choice of foods, meal timing and is adaptable to any situation. The basic outline behind flexible dieting is establishing your goal (weight gain, fat loss etc), working out the total calorie intake needed to achieve this, separating those calories into protein, carbohydrate and fat (macronutrient) ratios and then planning your food around these.
Once you know your macronutrient ratios and then targets, you can pick any foods you want to match these. It is always recommended to include enough wholesome, healthful foods to cover your vitamin, mineral and fibre needs first but once these are covered you can enjoy some of the foods that are excluded from most diets (as long as they fit within your macro/calorie targets). It also gives the opportunity to enjoy events, taking one of 2 options. Firstly, you can save on your calories through a day to fit an evenings food into your overall plan or secondly, you can enjoy the occasional night out/trip away knowing that over months of planned nutrition, the occasional variation is going to have minimal effect and do you no lasting harm (just don't try this every week).
Hopefully this approach can offer a long term solution to 'dieting' that removes the feelings of guilt while enabling you to enjoy yourself more at the same time. A step by step guide will follow soon, keep an eye out for Diet DIY.