Any kind of diet that eliminates multiple foods or groups of foods might make you feel better but it may be for reasons other than the rationale for the diet. Of course there is a possibility that some lucky people really landed on the diet that their body needs. But the more restrictive the diet the more likely it seems that it will appear to help but for reasons other than why it is supposed to help.
You might have an allergy, sensitivity, or intolerance to one or more of the foods that luckily have been among those foods or groups forbidden in a restrictive diet. They also usually remove processed foods and make eating out difficult or limited, further increasing the possibility that your particular sensitivity may be included.
I first realized this while trying the failsafe diet. You may indeed feel much better, but what if that is because your problem food happened to be among the many foods the diet restricts, not because you are reacting to those food chemicals? A similar pitfall may exist with any other fairly restrictive diet. Paleo, low fodmaps, low carb, candida are some examples that come to mind. Eliminating corn, soy, or sugar reduces processed foods greatly.