I guess the answer to whether calorie restriction is worth it all comes down to how far you take it. In my opinion the word restriction isn't a great one. I don't think you should 'restrict' anything from your diet, you should simply have things in moderation and by including ALL foods, your having a balanced diet!
Whether were talking about lowering calories, cutting out certain foods or changing the way we eat there are certainly some do's and dont's that are worth discussing! The biggest thing I think people seem to hold onto is that if they eat less they will lose fat. This is not entirely true! One thing that may happen is that you will lose weight to start with, but as you are on an unsustainable diet for the long term, as soon as you resume normal eating habits after shedding the pounds you wanted, you are likely to put it all back on - most put on more and end up bigger than they were before the diet! The second thing that may happen is that you could end up putting on weight when eating less. I know this sounds completely backwards, but its true. If you starve your body of what it needs, the body goes into 'starvation mode' and essentially anything you eat it will store as it doesn't know when it's next going to get fed. It's your bodies way of surviving, but all it means to you is that you gain fat. Not ideal!
Meal replacements are something that are commercially available, put in the supermarkets and saturated within the celeb endorsed media! They essentially are liquid drinks that you replace either 1 or 2 meals a day with (on average) and your supposed to lose weight. These can mean that you consume less calories than your normal meals, mainly if your used to having large lunches filled with saturated fats, and can mean that you have a routine to stick to. The downside and the reason that I would NEVER suggest using these is that they are not sustainable. Not only are they often filled with sugar (more than you would have normally) to give you energy, they are expensive and when you decide to stop the drinks and resume your normal diet - your body will do what I said above, store everything and make you put it straight back on! I must also add that this is the same for 'juicing' diets too.
Cutting out food groups as a form of 'cleanse' is another thing that can cause you to regain the weight very quickly. Cutting out any food group isn't a good idea due to the fact that our bodies need certain nutrients to survive and each food group has their roles in keeping us healthy and happy! The food group that most people cut out is carbohydrates and its something that I have tried myself. I've done stages of Ketosis where you essentially have no carbohydrates, however you don't realise how many foods have carbohydrates in, even carrots! The only upside I found is that I bloated less, which was the reason why I cut out the carbohydrates mainly, however since switching to an almost gluten free diet (can't resist sometimes) I've bloated far less and have less stomach upset! The downside to cutting out carbohydrates is the fact that you feel fatigued, grumpy and unable to function very well! You have to be careful also that you don't drop your calories too low by doing this also and to keep up your protein intake!
In general restricting calories too much isn't a sustainable way to lose weight and keep it off. I recommend tapering your calories down slowly without doing a 'crash' diet. Yes this does mean that your results are slower, but it means that you keep the weight off! If the end goal is to maintain your weight loss, then avoid a quick fix. If you stick to a healthy, balanced diet, with a cheat meal a week and nothing drastic then you will be fine!
If you do need help or advice just give me a message and I can explain further or answer any questions.