One of the tenets of the Whole30 diet is that your weight losses don't matter (as much as other health improvements, anyway) and that you shouldn't weigh yourself during the first 30 days. That's really difficult for me to do since I'm usually so obsessed with "knowing my numbers". Instead, I have to rely on signs like how tight or loose my clothing feels and how tightly I do up my belt. Based on that alone, I feel like I've neither lost much nor gained anything during the first five days of my Whole30 diet.
Here's what I've noticed about my own journey. I've eaten more fruit in the last week than I have in the past. I had previously been avoiding a lot of fruit because of the fructose in it. So many other things are verbotten that being able to snack on a clementine or a banana or some berries is quick and easy.
I've been eating a lot more avocados than usual, which is not a problem for me because I love them. I've also made more snacks with celery and crunchy almond butter than I ever used to in the past. Surprisingly (to me) my consumption of eggs hasn't increased (although, to be fair, it was already quite high compared to other people). And the amount of meat that I've eaten is slightly higher than on my former "diet".
Preparing meals (using wholesome, fresh ingredients) takes longer when you take away the convenience of packaged (albeit minimally processed) foods. And some of the "alternatives" (sugar- and nitrate-free bacon, for example) are more expensive than their conventional counterparts.
The thing I miss most is definitely cheese! Drinking coffee unsweetened (not even with stevia) is not as much fun as it is with a dash of dairy creamer or the luxury of hot frothy, whipped (or steamed) milk.
It's still too early to tell if there have been any other significant changes such as tiredness or energy levels. At this time I'd have to say that I'm glad it's only for 30 days. It might be good to do for a "reset" from time to time, but it's not the kind of diet I could happily follow for a sustained period of time.